Hydroplaning

Hydroplaning is perhaps one of the most terrifying things that can take place to any driver short of being engaged in a major collision. There you are, cruising along at fifty or sixty miles per hour in the rain, and all of a sudden your car is out of control. Several drivers don’t have a clue as to why their car abruptly ceased to respond to their turning of the steering wheel the application of the brakes. Frequently, drivers who are questioned after a crash caused by hydroplaning will state, “I don’t know what occurred, but I couldn’t control the vehicle.”

The one thing all hydroplaning problems have in common is the presence of water on the roadway. Here is what occurs when a hydroplaning vehicle is out of control: As the tires roll over the surface of a road that is wet after or during a heavy rain or when water has accumulated because of poor drainage, a wedge of water builds up just in front of the tire where it meets the road. If your tires are in good shape, they will flush away the wedge of water at lower speeds and allow the tire tread to grip the road for steering and braking. But when tires are worn or bald, the wedge of water does no get flushed away and the tires actually climb up on top of the wedge, losing contact with the road. Once the tires are floating on the water, the car is hydroplaning. The deeper the water, the more likely a hydroplane will occur. At slow speed, the tire simply squeezes the water away. At higher speeds, it is harder to flush away the water. Tires with deep tire treads and tires specifically designed as “rain tires” work best. But even the best tires may hydroplane at higher speeds. And worn tires may start to hydroplane at speeds as low as 30 mph. The best advice for any driver encountering water on the roadway is to slow down. It is nearly impossible to know the depth of water on a roadway. Aside from hydroplaning, driving fast into water may cause a splash that could momentarily blind you or a nearby driver. Hitting water at high speeds may also cause water to splash up under the hood and cause the engine to die out. That could leave you dangerously stranded on a busy lane where following cars have minimal control.

Again the most important thing to remember – no mater how good your tires are, no matter if you have antilock brakes, four-wheel drive or traction control – is to slow down!

Your best safeguard against a potentially out-of-control hydroplaning experience is to slow down to below 30 mph when the roadway is covered with water and to avoid any puddles of accumulated water on the roadway.

MINIMIZE YOUR RISK OF HYDROPLANING BY TAKING A FEW PRECAUTIONS:

*Make sure that all four of the tires on your car are in good condition. That means they must have a good amount of tread left that will allow water to be flushed out of the path of the tire as it meets the road. Ask your service dealer to measure the tire tread depth and advise you if it is adequate to keep you safe.

*In rainy weather, slow down to a safe speed. If need be, pull off the road in a dangerous downpour with limited visibility and a high risk of hydroplaning.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

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Dashboard Gauges

The minimum number of gauges on a passenger car dashboard is the speedometer and the fuel gauge. The most common additional gauge is the temperature gauge followed by the tachometer, voltmeter and oil pressure gauge. If your car does not have a temperature gauge, oil pressure gauge or charging system gauge, then you will have a warning light for these functions.

The most common configuration in today’s family car is: Speedometer, Tachometer, Fuel & Temperature.

Typical instrument panel

Note: To find out more about the gauges on your car, the best source of information is your owner’s manual.

• Speedometer
  In the past, the most used of the gauges. The speedometer was usually driven by a cable that spins inside a flexible tube.  The cable is connected on one side to the speedometer, and on the other side to the speedometer gear inside the transmission.  Today, just about all vehicles have eliminated the cable and use an electronic sensor to measure wheel speed and send the signal to an electronically driven speedometer.

The accuracy of the speedometer can be affected by the size of the tires. If the tires are larger in diameter than original equipment, the speedometer will read that you are going slower then you actually are.  On older vehicles, another cause for inaccurate speed readings was an improper speedometer gear inside the transmission. This can sometimes happen after a replacement transmission has been installed.  Most good transmission shops are aware of this and will make sure that the correct speedometer gear is in the new transmission.

On vehicles with electronic speedometers, the computer has settings to for speedometer calibration when necessary, to allow a technician to adjust for different sized tires. These calibrations usually require specialized equipment like diagnostic scanners to do these types of adjustments.

• Fuel Gauge

Deliberately designed to be inaccurate! After you fill up the tank, the gauge will stay on full for a long time, then slowly drop until it reads 3/4 full. After that, it moves progressively faster until the last quarter of a tank seems to go very quickly. This is a bit of psychological slight-of-hand to give the impression that the car gets better gas mileage than it does, it seems to reduce the number of complaints from new car buyers during the first few weeks after they bought the car.
The fuel gauge shown here is probably more accurate than most. Notice the difference between 3/4 to full and empty to 1/4.
When the needle drops below E, there is usually 1 or 2 gallons left in reserve. To find out for sure, pull out your owner’s manual and find out how many gallons of gas your tank holds, then the next time you fill up an empty tank, check how many gallons it took to fill it. The difference is your reserve.
Note: It is not a good idea to let your tank drop below 1/4.  This is because your fuel pump is submerged in fuel at the bottom of the tank.  The liquid fuel helps to keep the fuel pump cool.  If the fuel level goes too low and uncovers the pump, the pump will run hotter than normal.  If you do this often enough, it can shorten the life of the fuel pump and eventually cause it to fail.

• Temperature Gauge or warning lamp
  This gauge measures the temperature of the engine coolant in degrees. When you first start the car, the gauge will read cold. If you turn the heater on when the engine is cold, it will blow cold air. When the gauge starts moving away from cold, you can then turn the heater on and get warm air. Most temperature gauges do not show degrees like the one pictured here. Instead they will read cold, hot, and have a normal range as pictured in the dash panel at the top of this page.

It is very important to monitor the temperature gauge to be sure that your engine is not overheating. If you notice that the gauge is reading much hotter than it usually is and the outside temperature is not unusually hot, have the cooling system checked as soon as possible. Note: If the temperature gauge moves all the way to hot, or if the temperature warning light comes on, the engine is overheating! Safely pull off the road and turn the engine off and let it cool. An overheating engine can quickly cause serious engine damage!

• Tachometer
  The tachometer measures how fast the engine is turning in RPM (Revolutions Per Minute). This information is useful if your car has a standard shift transmission and you want to shift at the optimum RPM for best fuel economy or best acceleration. One of the least used gauges on a car with an automatic transmission. You should never race your engine so fast that the tach moves into the red zone as this can cause engine damage. Some engines are protected by the engine computer from going into the red zone.  Usually, the tachometer shows single digit markings like 1, 2, 3 etc. Somewhere, you will also see an indicator that says RPM x 1000.  This means that you multiply the reading by 1000 to get the actual RPM, so if the needle is pointing to 2, the engine is running at 2000 RPM.
• Oil Pressure Gauge or warning lamp
  Measures engine oil pressure in pounds per square inch. Oil pressure is just as important to an engine as blood pressure is to a person. If you run an engine with no oil pressure even for less than a minute, you can easily destroy it. Most cars have an oil lamp that lights when oil pressure is dangerously low. If it comes on while you’re driving, stop the vehicle as soon as is safely possible and shut off the engine. Then, check the oil level and add oil as necessary.
• Charging system gauge or warning lamp
  The charging system is what provides the electrical current for your vehicle. Without a charging system, your battery will soon be depleted and your vehicle will shut down. The charging system gauge or warning lamp monitors the health of this system so that you have a warning of a problem before you get stuck.
  When a charging problem is indicated, you can still drive a short distance to find help unlike an oil pressure or coolant temperature problem which can cause serious engine damage if you continue to drive. The worst that can happen is that you get stuck in a bad location.
  A charging system warning lamp is a poor indicator of problems in that there are many charging problems that it will not recognize. If it does light while you are driving, it usually means the charging system is not working at all. The most common cause is a broken alternator belt.
  There are two types of gauges used to monitor charging systems: a voltmeter which measures system voltage and an ammeter which measures amperage going out of, or coming into the battery. Most modern cars that have gauges use a voltmeter because it is a much better indicator of charging system health. A voltmeter is usually the first tool a technician uses when checking out a charging system

A modern automobile has a 12 volt electrical system. A fully charged battery will read about 12.5 volts when the engine is not running. When the engine is running, the charging system takes over so that the voltmeter will read 14 to 14.5 volts and should stay there unless there is a heavy load on the electrical system such as wipers, lights, heater and rear defogger all operating together while the engine is idling at which time the voltage may drop. If the voltage drops below 12.5, it means that the battery is providing some of the current. You may notice that your dash lights dim at this point. If this happens for an extended period, the battery will run down and may not have enough of a charge to start the car after shutting it off. This should never happen with a healthy charging system because as soon as you step on the gas, the charging system will recharge the battery. If the voltage is constantly below 14 volts, you should have the system checked. If the voltage ever goes above 15 volts, there is a problem with the voltage regulator. Have the system checked as soon as possible as this “overcharging” condition can cause damage to your electrical system.

If you think of electricity as water, voltage is like water pressure, whereas amperage is like the volume of water. If you increase pressure, then more water will flow through a given size pipe, but if you increase the size of the pipe, more water will flow at a lower pressure. An ammeter will read from negative amperage when the battery is providing most of the current thereby depleting itself, to positive amperage if most of the current is coming from the charging system. If the battery is fully charged and there is minimal electrical demand, then the ammeter should read close to zero, but should always be on the positive side of zero. It is normal for the ammeter to read high positive amperage in order to recharge the battery after starting, but it should taper off in a few minutes. If it continues to read more than 10 or 20 amps even though the lights, wipers and other electrical devices are turned off, you may have a weak battery and should have it checked.

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All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Maintenance Intervals

Vehicle System or Component	Check Monthly	Check Every 3,000 Miles	Service Notes
Automatic Transmission Fluid	Yes		Check level with engine running and transmission in park. If low, add type of ATF specified in owners’ manual and/or on dipstick. For best results change every two years or 24,000 miles
Battery and Cables		Yes	Battery should be securely mounted. Battery connections should be clean, tight and corrosion-free. If your car’s battery is three years old or more, it should be replaced
Belts		Yes	Check for looseness, cracks or glazing. Replace V-belts every four years/36,000 miles. Replace serpentine belts every four years/50,000 miles, or sooner if needed. Replace belt per interval specified in owner’s manual. Typically, this is at 60,000 miles. Not replacing the belt as required could cause a breakdown or serious engine damage
Brakes and Brake Fluid	Yes		For best results, have the entire brake system – including brake linings – inspected at every other oil change.
Cabin Air Filter			Replace annually, more often in areas with heavy airborne contaminants
Chassis Lubrication		Yes	Many newer cars are lubed-for-life, some still require this service. Replacement steering and suspension components require periodic lubrication.
Check Engine Light On	Yes		If light comes on while driving or remains on, your engine may have an emissions or sensor problem and should be checked by a professional technician. If light flashes, the condition is more severe and must be checked immediately to prevent catalytic converter damage.
Coolant (Antifreeze)	Yes		Check level at reservoir. Do not open hot radiator cap. If low, add 50/50 mix of approved antifreeze and distilled water.
Engine Air Filter		Yes	Replace yearly, or when dirty. Inspect annually, more often if driving and road conditions dictate.
Engine Oil and Filter	Yes	Yes	Check level with engine off at every fill up. Change oil and filter every 3,000 miles or 3 months. Use specified oil grade and weight.
Exhaust		Yes	Inspect for leaks, damage and broken supports or hangers if there is an unusual noise. If you suspect a problem, have it inspected immediately by a professional technician.
Fuel Filter		Yes	On carbureted cars, replace the filter once a year. On cars with fuel injection, replace the filter every two years or 24,000 miles.
Hoses		Yes	Inspect for leaks, cracks or bulges, sponginess, brittleness and swelling. Replace hoses at lease every four years.
Lights	Yes		Replace bulb immediately if light is out.
Power Steering Fluid		Yes	Check the fluid with the car warmed up. Add approved type if low. If regular topping off is required, have system inspected for leaks.
Shock Absorbers and Struts		Yes	Inspect for leaks, damage and loose mounting hardware. Replace if worn, damaged or leaking. Have checked by a professional at lease once a year.
Tire Inflation and Condition	Yes		Inflate tires to recommended pressure. Replace tires if worn or damaged. Remember to check the spare. Check pressure of all tires including the spare. Check tread for wear and for cuts or bruised along the sidewalls.
Windshield Washer Fluid	Yes		Check level every other fill up. Some vehicles have two reservoirs. Do not use water. Use washer fluid only.
Wiper Blades		Yes	Replace when streaking or chattering.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Helpful Tips

Today’s cars, light trucks, and sport-utility vehicles are high-tech marvels with digital dashboards, oxygen sensors, electronic computers, unibody construction, and more. They run better, longer, and more efficiently than models of years past.

But when it comes to repairs, some things stay the same. The following tips should help you along the way:

Do your homework before taking your vehicle in for repairs or service.

• Read the owner’s manual to learn about the vehicle’s systems and components.
• Follow the recommended service schedules.
• Keep a log of all repairs and service.

When you think about it, you know your car better than anyone else. You drive it every day and know how it feels and sounds when everything is right. So don’t ignore its warning signals.

Use all of your senses to inspect your car frequently. Check for:

• Unusual sounds, odors, drips, leaks, smoke, warning lights, gauge readings.
• Changes in acceleration, engine performance, gas mileage, fluid levels.
• Worn tires, belts, hoses.
• Problems in handling, braking, steering, vibrations.
• Note when the problem occurs.
• Is it constant or periodic?
• When the vehicle is cold or after the engine has warmed up?
• At all speeds? Only under acceleration? During braking? When shifting?
• When did the problem first start?

Once you are at our location, communicate your findings.

• Be prepared to describe the symptoms.
• Carry a written list of the symptoms that you can give us.
• Resist the temptation to suggest a specific course of repair. Just as you would with your physician, tell us where it hurts and how long it’s been that way, but let the technician diagnose and recommend a remedy.

Stay involved. . . Ask questions.

• Ask as many questions as you need. Do not be embarrassed to request lay definitions.
• Don’t rush the technician to make an on-the-spot diagnosis. You may ask to be called and apprised of the problem, course of action, and costs before work begins.
• Before you leave, be sure you understand all shop policies regarding labor rates, guarantees, and acceptable methods of payment.
• Leave a telephone number where you can be called.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Ten Ways to Save on Gas

1) Keep starts and stops smooth.
Nailing the pedal to the floor in “jackrabbit starts” wastes gas. Abrupt stops also waste fuel—and cause extra wear and tear.

2) Perform routine car care.
Dirty air filters and oil filters, worn spark plugs, neglected oil changes and problems with the emission-control system can reduce fuel economy. Change your oil and check the filters every 3000 miles for peak performance.

3) Maintain tires and keep wheels aligned.
Low tire air pressure is dangerous—and costly. It creates a drag on the engine, prematurely wears out tires and burns more gas. Misaligned wheels, worn wheel bearings or dragging brakes also can reduce fuel economy by 10%.

4) Buy the right octane.
Most cars work fine on regular gas (unless you hear an engine knock). But you should use the octane the manufacturer specifies.

5) Use your air conditioner wisely.
Running your air conditioner greatly increases gas consumption. Don’t use it if fresh air will cool the vehicle sufficiently. On hot days, park in the shade and open the windows for a few minutes when you get in to let hot air escape.

6) Lighten the load.
Don’t use your trunk to store stuff—extra tires, beach chairs, a case of motor oil. Added weight lowers fuel economy. A rooftop luggage rack also creates a drag that will reduce mileage.

7) Stay out of traffic.
Stop-and-go traffic takes a drastic toll on fuel usage. If at all possible, plan your trips to avoid periods of peak traffic congestion. Also try to avoid unnecessary idling, which burns more gas than turning off and restarting the engine.

Drive smart.
First, keep your speed down: Going 65 mph uses about 15% more fuel than going 55mph, and going 70 to 75 mph may consume 25% more. Second, keep a constant speed—use cruise control if you can. Finally, use overdrive if you have it(most vehicles with automatic transmissions do). That way, the car will shift into gas-saving mode at about 50 mph.

9) Plan your errands.
Taking frequent short trips will guzzle gas. Instead, try to combine errands with your daily commute: Pick up your dry cleaning on the way home from work, for example.

10) Fill up in the morning.
You’ll get slightly more fuel for your dollar if you fill up when it’s cooler outside. (Cooler gasoline is more compact.) Over time, the savings can add up!

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Driving Tips for Mom’s-to-Be

With all of the excitement surrounding moms-to-be, transportation is the least of the worries, however driving while pregnant can be a very uncomfortable situation. Here are tips to new and expectant mothers for safe and comfortable car rides.

Many pregnant women may find driving to be less than comfortable, worrying if their belly is too close to the steering wheel, not quite sure how to deal with the seat belt, and the thought of airbags protecting their unborn child.

Although sometimes unpleasant, you should always wear a seat belt. The proper way to wear a seat belt while pregnant is no different from any other time. Make sure that the lap belt is low and tight across your hips, not across your stomach. The shoulder belt should go across the middle of your chest and away from your neck. Many vehicles allow for adjustment of the belt at the car’s “B” pillar (the middle post over your shoulder).

Airbags are proven to save lives—if they are used with seat-belts and if the passenger is seated properly and the right distance from the airbags. Expectant mothers should be sure to sit up straight and keep at least 12 inches of clearance between the front airbags and their belly. Pillows or other cushions should not be used to change seating position, simply use the adjusters that are built into the vehicle.

Below are answers to other common questions for choosing the best cars for new moms.

- Pregnant women and new mom’s are already dealing with all the gear they have to carry – what vehicle can hold it all and which are the easiest autos to load and unload?
Look for low vehicles that are safe such as Crossover or Sport utility vehicles. Also consider minivans and station wagons. The secret is to haul all the gear without putting more stress on your back.


- What auto will put the least pressure on your back?
Lower vehicles, but not too low like CUV’s, are best as you can get car seats in and out and are not too high so you don’t strain your back. This is personal based on height and body structure.

- Which vehicles are the easiest to install a car seat?
Minivans are easiest so you can sit in the vehicle if needed and buckle in the belt. Please always follow the owner’s manual and the car seat directions for the correct way to install the seat.

- As the kids grow – will this vehicle grow with it?
Kids love to look out the window at any age. Look for adjustable seats and never use a pillow or blanket to raise a car seat.

- What can you add to a car to protect children from the sun?
Static window tint and shades are available to protect your child from the sun or bright light that may upset a child or baby.

- What are the safest vehicles to protect your children?
Always look for a five- star crash test rating for the front driver and passenger as well as both sides for side impact protection. Children travel safest when they wear their seat-belts, you should set a good example, but the safest vehicles have air bags in the front and side. Car seats are the safest way for small children to travel as long as they’re properly attached to the car.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Safe Winter Driving

Here are a few driving tips to prepare drivers for the winter weather conditions on the road ahead.

As winter sets in, the roads can become a treacherous place for a vehicle. Heavy rain, snow, sleet, and ice can create a whole new world on the road than what most are used to driving on. Don’t be caught off guard when the weather turns frightful, and review these tips before taking to the streets come the first sign of winter.

1) ADJUST YOUR SPEED TO THE CURRENT CONDITIONS.
When driving in challenging conditions, slow down. Decreasing speed will allow more time to respond when a difficult situation occurs.

2) ANTICIPATE DIFFICULT SITUATIONS.
Many studies have shown that 80% of all accidents could be prevented with only one more second to react. This one second can be gained by looking far enough ahead of to identify problems before becoming a part of them.

3) USE GRIP EFFECTIVELY.
When roads are slippery, always brake in a straight line before the curve in the road. Taking your foot off the brake before steering into the corner allows you to use the entire grip available for steering. Don’t accelerate until the steering wheel is straight.

4) DRIVE WITH YOUR HEADLIGHTS ON.
Whenever daytime visibility is less than clear be sure to turn on head lights as to be seen by other drivers. Remember this rule of thumb: wipers on, lights on. When traveling in snowy weather remember to regularly clear tail lights, turn signal lights, and headlamps.

5) ANTI-LOCK BRAKES CAN’T PERFORM MIRACLES.
Although ABS braking systems offer the ability to brake and steer, they are still limited by the grip available on the road and the type of tires on your vehicle. If you’re driving too fast into a corner and try to brake, even ABS won’t keep you on the road.

6) DRIVING AT NIGHT.
Leave headlamps on low beam when driving in snow or fog. This will minimize the reflection and glare, improve visibility, and will help reduce eye fatigue.

7) WEAR QUALITY SUNGLASSES.
Good-quality sunglasses help highlight changes in the terrain and road surface even in low visibility conditions. Polarized lenses are your best choice.

Start the winter off right by reviewing and following these simple guidelines to prepare for the slippery conditions that lie ahead.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Ignition System

The purpose of the ignition system is to create a spark that will ignite the fuel-air mixture in the cylinder of an engine.  It must do this at exactly the right instant and do it at the rate of up to several thousand times per minute for each cylinder in the engine.  If the timing of that spark is off by a small fraction of a second, the engine will run poorly or not run at all.

The ignition system sends an extremely high voltage to the spark plug in each cylinder when the piston is at the top of its compression stroke.  The tip of each spark plug contains a gap that the voltage must jump across in order to reach ground.  That is where the spark occurs.

The voltage that is available to the spark plug is somewhere between 20,000 volts and 50,000 volts or better.  The job of the ignition system is to produce that high voltage from a 12 volt source and get it to each cylinder in a specific order, at exactly the right time.

Let’s see how this is done.

The ignition system has two tasks to perform.  First, it must create a voltage high enough (20,000+) to arc across the gap of a spark plug, thus creating a spark strong enough to ignite the air/fuel mixture for combustion.  Second, it must control the timing of that the spark so it occurs at the exact right time and send it to the correct cylinder.

The ignition system is divided into two sections, the primary circuit and the secondary circuit.  The low voltage primary circuit operates at battery voltage (12 to 14.5 volts) and is responsible for generating the signal to fire the spark plug at the exact right time and sending that signal to the ignition coil.  The ignition coil is the component that converts the 12 volt signal into the high 20,000+ volt charge.  Once the voltage is stepped up, it goes to the secondary circuit which then directs the charge to the correct spark plug at the right time.

The Basics
Before we begin this discussion, let’s talk a bit about electricity in general.  I know that this is basic stuff, but there was a time that you didn’t know about this and there are people who need to know the basics so that they could make sense of what follows.

All automobiles work on DC, or Direct Current.   This means that current moves in one direction, from the positive battery terminal to the negative battery terminal.  In the case of the automobile, the negative battery terminal is connected by a heavy cable directly to the body and the engine block of the vehicle.  The body and any metal component in contact with it is called the Ground.  This means that a circuit that needs to send current back to the negative side of the battery can be connected to any part of the vehicle’s metal body or the metal engine block.

A good example to see how this works is the headlight circuit.  The headlight circuit consists of a wire that goes from the positive battery terminal to the headlight switch.  Another wire goes from the headlight switch to one of two terminals on the headlamp bulb.  Finally, a third wire goes from a second terminal on the bulb to the metal body of the car.  When you switch the headlights on, you are connecting the wire from the battery with the wire to the headlamps allowing battery current to go directly to the headlamp bulbs.  Electricity passes through the filaments inside the bulb, then out the other wire to the metal body.  From there, the current goes back to the negative terminal of the battery completing the circuit.  Once the current is flowing through this circuit, the filament inside the headlamp gets hot and glows brightly.  Let there be light.

Now, back to the ignition system.  The basic principle of the electrical spark ignition system has not changed for over 75 years. What has changed is the method by which the spark is created and how it is distributed.

Currently, there are three distinct types of ignition systems,  The Mechanical Ignition System was used prior to 1975.  It was mechanical and electrical and used no electronics.  By understanding these early systems, it will be easier to understand the new electronic and computer controlled ignition systems, so don’t skip over it.  The Electronic Ignition System started finding its way to production vehicles during the early ’70s and became popular when better control and improved reliability became important with the advent of emission controls.  Finally, the Distributorless Ignition System became available in the mid ’80s.  This system was always computer controlled and contained no moving parts, so reliability was greatly improved.  Most of these systems required no maintenance except replacing the spark plugs at intervals from 60,000 to over 100,000 miles.

Let’s take a detailed look at each system and see how they work.
The Mechanical Ignition System
(from the dawn of the automobile to 1974)

The distributor is the nerve center of the mechanical ignition system and has two tasks to perform.  First, it is responsible for triggering the ignition coil to generate a spark at the precise instant that it is required (which varies depending how fast the engine is turning and how much load it is under).  Second, the distributor is responsible for directing that spark to the proper cylinder (which is why it is called a distributor)

The circuit that powers the ignition system is simple and straight forward. (see above)  When you insert the key in the ignition switch and turn the key to the Run position, you are sending current from the battery through a wire directly to the positive (+) side of the ignition coil.  Inside the coil is a series of copper windings that loop around the coil over a hundred times before exiting out the negative (-) side of the coil.  From there, a wire takes this current over to the distributor and is connected  to a special on/off switch, called the points.  When the points are closed, this current goes directly to ground.  When current flows from the ignition switch, through the windings in the coil, then to ground, it builds a strong magnetic field inside the coil.

The points are made up of a fixed contact point that is fastened to a plate inside the distributor, and a movable contact point mounted on the end of a spring loaded arm.. The movable point rides on a 4,6, or 8 lobe cam (depending on the number of cylinders in the engine) that is mounted on a rotating shaft inside the distributor.  This distributor cam rotates in time with the engine, making one complete revolution for every two revolutions of the engine.  As it rotates, the cam pushes the points open and closed.  Every time the points open, the flow of current is interrupted through the coil, thereby collapsing the magnetic field and releasing a high voltage surge through the secondary coil windings.  This voltage surge goes out the top of the coil and through the high-tension coil wire.

Now, we have the voltage necessary to fire the spark plug, but we still have to get it to the correct cylinder.  The coil wire goes from the coil directly to the center of the distributor cap.  Under the cap is a rotor that is mounted on top of the rotating shaft.  The rotor has a metal strip on the top that is in constant contact with the center terminal of the distributor cap.  It receives the high voltage surge from the coil wire and sends it to the other end of the rotor which rotates past each spark plug terminal inside the cap.  As the rotor turns on the shaft, it sends the voltage to the correct spark plug wire, which in turn sends it to the spark plug.  The voltage enters the spark plug at the terminal at the top and travels down the core until it reaches the tip.  It then jumps across the gap at the tip of the spark plug, creating a spark suitable to ignite the fuel-air mixture inside that cylinder.

The description I just provided is the simplified version, but should be helpful to visualize the process, but we left out a few things that make up this type of ignition system.  For instance, we didn’t talk about the condenser that is connected to the points, nor did we talk about the system to advance the timing.  Let’s take a look at each section and explore it in more detail.

The ignition switch
There are two separate circuits that go from the ignition switch to the coil.  One circuit runs through a resistor in order to step down the voltage about 15% in order to protect the points from premature wear.  The other circuit sends full battery voltage to the coil.  The only time this circuit is used is during cranking.  Since the starter draws a considerable amount of current to crank the engine, additional voltage is needed to power the coil.  So when the key is turned to the spring-loaded start position, full battery voltage is used.  As soon as the engine is running, the driver releases the key to the run position which directs current through the primary resistor to the coil.

On some vehicles, the primary resistor is mounted on the firewall and is easy to replace if it fails.  On other vehicles, most notably vehicles manufactured by GM, the primary resistor is a special resistor wire and is bundled in the wiring harness with other wires, making it more difficult to replace, but also more durable.

The Distributor
When you remove the distributor cap from the top of the distributor, you will see the points and condenser.  The condenser is a simple capacitor that can store a small amount of current.  When the points begin to open, the current flowing through the points looks for an alternative path to ground.  If the condenser were not there, it would try to jump across the gap of the points as they begin to open.  If this were allowed to happen, the points would quickly burn up and you would hear heavy static on the car radio.  To prevent this, the condenser acts like a path to ground. It really is not, but by the time the condenser is saturated, the points are too far apart for the small amount of voltage to jump across the wide point gap.  Since the arcing across the opening points is eliminated, the points last longer and there is no static on the radio from point arcing.

The points require periodic adjustments in order to keep the engine running at peek efficiency.  This is because there is a rubbing block on the points that is in contact with the cam and this rubbing block wears out over time changing the point gap.  There are two ways that the points can be measured to see if they need an adjustment.  One way is by measuring the gap between the open points when the rubbing block is on the high point of the cam.  The other way is by measuring the dwell electrically.  The dwell is the amount, in degrees of cam rotation, that the points stay closed.

On some vehicles, points are adjusted with the engine off and the distributor cap removed.  A mechanic will loosen the fixed point and move it slightly, then retighten it in the correct position using a feeler gauge to measure the gap.  On other vehicles, most notably GM cars, there is a window in the distributor where a mechanic can insert a tool and adjust the points using a dwell meter while the engine is running.  Measuring dwell is much more accurate than setting the points with a feeler gauge.

Points have a life expectancy of about 10,000 miles at which time they have to be replaced. This is done during a routine major tune up.  During the tune up, points, condenser, and the spark plugs are replaced, the timing is set and the carburetor is adjusted.  In some cases, to keep the engine running efficiently, a minor tune up would be performed at 5,000 mile increments to adjust the points and reset the timing.

Ignition Coil
The ignition coil is nothing more that an electrical transformer.  It contains both primary and secondary winding circuits. The coil primary winding contains 100 to 150 turns of heavy copper wire. This wire must be insulated so that the voltage does not jump from loop to loop, shorting it out.  If this happened, it could not create the primary magnetic field that is required. The primary circuit wire goes into the coil through the positive terminal, loops around the primary windings, then exits through the negative terminal.

The coil secondary winding circuit contains 15,000 to 30,000 turns of fine copper wire, which also must be insulated from each other.  The secondary windings sit inside the loops of the primary windings.  To further increase the coils magnetic field the windings are wrapped around a soft iron core. To withstand the heat of the current flow, the coil is filled with oil which helps keep it cool.

The ignition coil is the heart of the ignition system. As current flows through the coil a strong magnetic field is built up. When the current is shut off, the collapse of this magnetic field to the secondary windings induces a high voltage which is released through the large center terminal.  This voltage is then directed to the spark plugs through the distributor.

Ignition Timing
The timing is set by loosening a hold-down screw and rotating the body of the distributor.  Since the spark is triggered at the exact instant that the points begin to open, rotating the distributor body (which the points are mounted on) will change the relationship between the position of the points and the position of the distributor cam, which is on the shaft that is geared to the engine rotation.

While setting the initial, or base timing is important, for an engine to run properly, the timing needs to change depending on the speed of the engine and the load that it is under.  If we can move the plate that the points are mounted on, or we could change the position of the distributor cam in relation to the gear that drives it, we can alter the timing dynamically to suit the needs of the engine.

Why do we need the timing to advance when the engine runs faster?
When the spark plug fires in the combustion chamber, it ignites whatever fuel and air mixture is present at the tip of the spark plug.  The fuel that surrounds the tip is ignited by the burning that was started by the spark plug, not by the spark itself.  That flame front continues to expand outward at a specific speed that is always the same, regardless of engine speed.  It does not begin to push the piston down until it fills the combustion chamber and has no where else to go.  In order to maximize the amount of power generated, the spark plug must fire before the piston reaches the top of the cylinder so that the burning fuel is ready to push the piston down as soon as it is at the top of its travel.  The faster the engine is spinning, the earlier we have to fire the plug to produce maximum power.

There are two mechanisms that allow the timing to change: Centrifugal Advance and Vacuum Advance.

Centrifugal Advance changes the timing in relation to the speed (RPM) of the engine.  It uses a pair of weights that are connected to the spinning distributor shaft.  These weights are hinged on one side to the lower part of the shaft and connected by a linkage to the upper shaft where the distributor cam is.  The weights are held close to the shaft be a pair of springs.  As the shaft spins faster, the weights are pulled out by centrifugal force against the spring pressure.  The faster the shaft spins, the more they are pulled out.  When the weights move out, it changes the alignment between the lower and upper shaft, causing the timing to advance.

Vacuum Advance works by changing the position of the points in relationship to the distributor body.  An engine produces vacuum while it is running with the throttle closed.  In other words, your foot is off the gas pedal.  In this configuration, there is very little fuel and air in the combustion chamber.

Vacuum advance uses a vacuum diaphragm connected to a link that can move the plate that the points are mounted on.  By sending engine vacuum to the vacuum advance diaphragm, timing is advanced.  On older cars, the vacuum that is used is port vacuum, which is just above the throttle plate.  With this setup, there is no vacuum present at the vacuum advance diaphragm while the throttle is closed.  When the throttle is cracked opened, vacuum is sent to the vacuum advance, advancing the timing.

On early emission controlled vehicles, manifold vacuum was used so that vacuum was present at the vacuum advance at idle in order to provide a longer burn time for the lean fuel mixtures on those engines.  When the throttle was opened, vacuum was reduced causing the timing to retard slightly.  This was necessary because as the throttle opened, more fuel was added to the mixture reducing the need for excessive advance.  Many of these early emission controlled cars had a vacuum advance with electrical components built into the advance unit to modify the timing under certain conditions.

Both Vacuum and Centrifugal advance systems worked together to extract the maximum efficiency from the engine.  If either system was not functioning properly, both performance and fuel economy would suffer.  Once computer controls were able to directly control the engine’s timing, vacuum and centrifugal advance mechanisms were no longer necessary and were eliminated.

Ignition Wires
These cables are designed to handle 20,000 to more than 50,000 volts, enough voltage to toss you across the room if you were to be exposed to it.  The job of the spark plug wires is to get that enormous power to the spark plug without leaking out.  Spark plug wires have to endure the heat of a running engine as well as the extreme changes in the weather.  In order to do their job, spark plug wires are fairly thick, with most of that thickness devoted to insulation with a very thin conductor running down the center.  Eventually, the insulation will succumb to the elements and the heat of the engine and begins to harden, crack, dry out, or otherwise break down. When that happens, they will not be able to deliver the necessary voltage to the spark plug and a misfire will occur.  That is what is meant by “Not running on all cylinders”.  To correct this problem, the spark plug wires would have to be replaced.

Spark plug wires are routed around the engine very carefully.  Plastic clips are often used to keep the wires separated so that they do not touch together.  This is not always necessary, especially when the wires are new, but as they age, they can begin to leak and crossfire on damp days causing hard starting or a rough running engine.

Spark plug wires go from the distributor cap to the spark plugs in a very specific order.  This is called the “firing order” and is part of the engine design.  Each spark plug must only fire at the end of the compression stroke.  Each cylinder has a compression stroke at a different time, so it is important for the individual spark plug wire to be routed to the correct cylinder.

For instance, a popular V8 engine firing order is 1, 8, 4, 3, 6, 5, 7, 2.  The cylinders are numbered from the front to the rear with cylinder #1 on the front-left of the engine.  So the cylinders on the left side of the engine are numbered 1, 3, 5, 7 while the right side are numbered 2, 4, 6, 8.  On some engines, the right bank is 1, 2, 3, 4 while the left bank is 5, 6, 7, 8.  A repair manual will tell you the correct firing order and cylinder layout for a particular engine.

The next thing we need to know is what direction the distributor is rotating in, clockwise or counter-clockwise, and which terminal on the distributor cap that #1 cylinder is located.  Once we have this information, we can begin routing the spark plug wires.

If the wires are installed incorrectly, the engine may backfire, or at the very least, not run on all cylinders.  It is very important that the wires are installed correctly.

Spark Plugs
The ignition system’s sole reason for being is to service the spark plug.  It must provide sufficient voltage to jump the gap at the tip of the spark plug and do it at the exact right time, reliably on the order of thousands of times per minute for each spark plug in the engine.

The modern spark plug is designed to last many thousands of miles before it requires replacement.  These electrical wonders come in many configurations and heat ranges to work properly in a given engine.

The heat range of a spark plug dictates whether it will be hot enough to burn off any residue that collects on the tip, but not so hot that it will cause pre-ignition in the engine.  Pre-ignition is caused when a spark plug is so hot, that it begins to glow and ignite the fuel-air mixture prematurely, before the spark.  Most spark plugs contain a resistor to suppress radio interference.  The gap on a spark plug is also important and must be set before the spark plug is installed in the engine.  If the gap is too wide, there may not be enough voltage to jump the gap, causing a misfire.  If the gap is too small, the spark may be inadequate to ignite a lean fuel-air mixture, also causing a misfire.

The Electronic Ignition System
(from 1970′s to today)

This section will describe the main differences between the early point & condenser systems and the newer electronic systems.  If you are not familiar with the way an ignition system works in general, I strongly recommend that you first read the previous section The Mechanical Ignition System.

In the electronic ignition system, the points and condenser were replaced by electronics.  On these systems, there were several methods used to replace the points and condenser in order to trigger the coil to fire.  One method used a metal wheel with teeth, usually one for each cylinder.  This is called an armature or reluctor.  A magnetic pickup coil senses when a tooth passes and sends a signal to the control module to fire the coil.

Other systems used an electric eye with a shutter wheel to send a signal to the electronics that it was time to trigger the coil to fire.  These systems still need to have the initial timing adjusted by rotating the distributor housing.

The advantage of this system, aside from the fact that it is maintenance free, is that the control module can handle much higher primary voltage than the mechanical points.  Voltage can even be stepped up before sending it to the coil, so the coil can create a much hotter spark, on the order of 50,000 volts instead of 20,000 volts that is common with the mechanical systems.  These systems only have a single wire from the ignition switch to the coil since a primary resistor is no longer needed.

On some vehicles, this control module was mounted inside the distributor where the points used to be mounted.  On other designs, the control module was mounted outside the distributor with external wiring to connect it to the pickup coil.  On many General Motors engines, the control module was inside the distributor and the coil was mounted on top of the distributor for a one piece unitized ignition system.  GM called it High Energy Ignition or HEI for short.

The higher voltage that these systems provided allow the use of a much wider gap on the spark plugs for a longer, fatter spark.  This larger spark also allowed a leaner mixture for better fuel economy and still insure a smooth running engine.

The early electronic systems had limited or no computing power, so timing still had to be set manually and there was still a centrifugal and vacuum advance built into the distributor.

On some of the later systems, the inside of the distributor is empty and all triggering is performed by a sensor that watches a notched wheel connected to either the crankshaft or the camshaft.  These devices are called Crankshaft Position Sensor or Camshaft Position Sensor.  In these systems, the job of the distributor is solely to distribute the spark to the correct cylinder through the distributor cap and rotor.  The computer handles the timing and any timing advance necessary for the smooth running of the engine.

The Distributorless Ignition system
(from 1980′s to today)

Newer automobiles have evolved from a mechanical system (distributor) to a completely solid state electronic system with no moving parts.  These systems are completely controlled by the on-board computer.  In place of the distributor, there are multiple coils that each serve one or two spark plugs.  A typical 6 cylinder engine has 3 coils that are mounted together in a coil “pack”.  A spark plug wire comes out of each side of the individual coil and goes to the appropriate spark plug.  The coil fires both spark plugs at the same time.  One spark plug fires on the compression stroke igniting the fuel-air mixture to produce power, while the other spark plug fires on the exhaust stroke and does nothing.  On some vehicles, there is an individual coil for each cylinder mounted directly on top of the spark plug.  This design completely eliminates the high tension spark plug wires for even better reliability.  Most of these systems use spark plugs that are designed to last over 100,000 miles, which cuts down on maintenance costs.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

Charging System

What is a Charging System?

The modern charging system hasn’t changed much in over 40 years.  It consists of the alternator, regulator (which is usually mounted inside the alternator) and the interconnecting wiring. The purpose of the charging system is to maintain the charge in the vehicle’s battery, and to provide the main source of electrical energy while the engine is running.

If the charging system stopped working, the battery’s charge would soon be depleted, leaving the car with a “dead battery.”   If the battery is weak and the alternator is not working, the engine may not have enough electrical current to fire the spark plugs, so the engine will stop running. If the battery is “dead”, it does not necessarily mean that there is anything wrong with it.  It is just depleted of its charge.  It can be brought back to life by recharging it with a battery charger, or by running the engine so that the alternator can charge it.

The main component in the charging system is the ALTERNATOR.  The alternator is a generator  that produces Alternating Current (AC), similar to the electrical current in your home.  This current is immediately converted to Direct Current (DC) inside the alternator.  This is because all modern automobiles have a 12 volt, DC electrical system.

A VOLTAGE REGULATOR regulates the charging voltage that the alternator produces, keeping it between 13.5 and 14.5 volts to protect the electrical components throughout the vehicle.

There is also a system to warn the driver if something is not right with the charging system.  This could be a dash mounted voltmeter, an ammeter, or more commonly, a warning lamp.  This lamp is variously labeled “Gen” Bat” and “Alt.”.  If this warning lamp lights up while the engine is running, it means that there is a problem in the charging system, usually an alternator that has stopped working.  The most common cause is a broken alternator drive belt.

Serpentine Belt: The alternator is driven by a belt that is powered by the rotation of the engine.  This belt goes around a pulley connected to the front of the engine’s crankshaft and is usually responsible for driving a number of other components including the water pump, power steering pump and air conditioning compressor.  On some engines, there is more than one belt and the task of driving these components is divided between them.  These belts are usually referred to as: Fan Belt, Alternator Belt, Drive Belt, Power Steering Belt, A/C Belt, etc.  More common on late model engines, one belt, called a Serpentine Belt will snake around the front of the engine and drive all the components by itself.

On engines with separate belts for each component, the belts will require periodic adjustments to maintain the proper belt tension.  On engines that use a serpentine belt, there is usually a spring loaded belt tensioner that maintains the tension of the belt, so no periodic adjustments are required. A serpentine belt is designed to last around 30,000 miles.  Check your owner’s manual to see how often yours should be replaced.

Alternator output is measured in both voltage and amperage.  To understand voltage and amperage, you must also know about resistance, which is measured in ohms.  An easy way to picture this is to compare the movement of electricity to that of running water.  Water flows through a pipe with a certain amount of pressure.  The size (diameter) of the pipe dictates how much resistance there will be to the flowing water.  The smaller the pipe, the more resistance.  You can increase the pressure to get more water to flow through, or you can increase the size of the pipe to allow more water to flow using less pressure.  Since too much pressure can burst the pipe, we should probably restrict the amount of pressure being used.  You get the idea, but how is this related to the flow of electricity?

Well, voltage is the same as water pressure.  Amperage is like the amount or volume of water flowing through, while resistance is the size of the wire transmitting the current.  Since too much voltage will damage the electrical components such as light bulbs and computer circuits, we must limit  the amount of voltage.  This is the job of the voltage regulator.  Too much water pressure and things could start breaking.  Too much voltage and things could start burning out.
Let’s get technical

Now, let’s go a little deeper and see how these charging system components actually work to produce the electrical power that a modern automobile requires.

The Alternator

• Alternator Stator – The alternator uses the principle of electromagnetism to produce current.  The way this works is simple.  If you take a strong magnet and pass it across a wire, that wire will generate a small voltage.  Take that same wire and loop it many times, than if you pass the same magnet across the bundle of loops, you create a more sizable voltage in that wire. There are two main components that make up an alternator.  They are the rotor and the stator.  The rotor is connected directly to the alternator pulley.  The drive belt spins the pulley, which in turn spins the rotor.  The stator is mounted to the body of the alternator and remains stationary.  There is just enough room in the center of the stator for the rotor to fit and be able to spin without making any contact. The stator contains 3 sets of wires that have many loops each and are evenly distributed to form a three phase system.  On some systems, the wires are connected to each other at one end and are connected to a rectifier assembly on the other end.  On other systems, the wires are connected to each other end to end, and at each of the three connection points, there is also a connection to the rectifier.  More on what a rectifier is later.

• Alternator Rotor – The rotor contains the powerful magnet that passes close to the many wire loops that make up the stator.  The magnets in the rotor are actually electromagnets, not a permanent magnets.  This is done so that we can control how much voltage the alternator produces by regulating the amount of current that creates the magnetic field in the rotor.  In this way, we can control the output of the alternator to suit our needs, and protect the circuits in the automobile from excessive voltage.

Now we know that every magnet has a north and a south pole and electro magnets are no exception.  Our rotor has two interlocking sections of electro magnets that are arranged so that there are fingers of alternating north and south poles, that are evenly distributed on the outside of the rotor. When we spin the rotor inside the stator and apply current to the rotor through a pair of brushes that make constant contact with two slip rings on the rotor shaft.  This causes the rotor to become magnetized.  The alternating north and south pole magnets spin past the three sets of wire loops in the stator and produce a constantly reversing voltage in the three wires.  In other words, we are producing alternating current in the stator.

Now, we have to convert this alternating current to direct current current.  This is done by using a series of 6 diodes that are mounted in a rectifier assembly.   A diode allows current to flow only in one direction.   If voltage tries to flow in the other direction, it is blocked.  The six diodes are arranged so that all the voltage coming from the alternator is aligned in one direction thereby converting AC current into DC current.

Typical Alternator Circuit -There are 2 diodes for each of the three sets of windings in the stator.  The two diodes are facing in opposite directions, one with its north pole facing the windings and the other with its south pole facing the windings.  This arrangement causes the AC current coming out of the windings to be converted to DC current before it leaves the alternator through the B terminal.  Connected to the B terminal of the alternator is a fairly heavy wire that runs straight to the battery.

Current to generate the magnetic field in the rotor comes from the ignition switch and passes through the voltage regulator.  Since the rotor is spinning, we need a way to connect this current from the regulator to the spinning rotor.  This is accomplished by wires connected to two spring loaded brushes that rub against two slip rings on the rotor’s shaft.  The voltage regulator monitors the voltage coming out of the alternator and, when it reaches a threshold of about 14.5 volts, the regulator reduces the current in the rotor to weaken the magnetic field.  When the voltage drops below this threshold, the current to the rotor is increased.

There is another circuit in the alternator to control the charging system warning lamp that is on the dash.  Part of that circuit is another set of diodes mounted inside the alternator called the diode trio.  The diode trio takes current coming from the three stator windings and passes a small amount through three diodes so that only the positive voltage comes through.  After the diodes, the wires are joined into one wire and sent out of the alternator at the L connection.  It then goes to one side of the dash warning lamp that is used to tell you when there is a problem with the charging system.  The other side of the lamp is connected to the run side of the ignition switch.  If both sides of the warning lamp have equal positive voltage, the lamp will not light.  Remove voltage from one side and the lamp comes on to let you know there is a problem.

This system is not very efficient.  There are many types of malfunctions of the charging system that it cannot detect, so just because the lamp is not lit does not mean everything is ok.  A volt meter is probably the best method of determining whether the charging system is working properly.
The Voltage Regulator
The voltage regulator can be mounted inside or outside of the alternator housing.  If the regulator is mounted outside (common on some Ford products) there will be a wiring harness connecting it to the alternator.

The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery. When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery. As the battery reaches a state of full charge, the electromotive force becomes strong enough to oppose the current flow from the alternator, the amperage output from the alternator will drop to close to zero, while the voltage will remain at 13.5 to 14.5. When more electrical power is used, the electromotive force will reduce and alternator amperage will increase. It is extremely important that when alternator efficiency is checked, both voltage and amperage outputs are checked. Each alternator has a rated amperage output depending on the electrical requirements of the vehicle.

Charging system gauge or warning lamp
The charging system gauge or warning lamp monitors the health of the charging system so that you have a warning of a problem before you get stuck.

When a charging problem is indicated, you can still drive a short distance to find help unlike an oil pressure or coolant temperature problem which can cause serious engine damage if you continue to drive. The worst that can happen with a charging system problem is that you get stuck in a bad location.

A charging system warning lamp is a poor indicator of problems in that there are many charging problems that it will not recognize. If it does light while you are driving, it usually means the charging system is not working at all. The most common cause of this is a broken alternator belt.

There are two types of gauges used to monitor charging systems on some vehicles: a voltmeter which measures system voltage and an ammeter which measures amperage. Most modern cars that have gauges use a voltmeter because it is a much better indicator of charging system health. A mechanic’s voltmeter is usually the first tool a technician uses when checking out a charging system

Typical Voltmeter – A modern automobile has a 12 volt electrical system. A fully charged battery will read about 12.5 volts when the engine is not running. When the engine is running, the charging system takes over so that the voltmeter will read 14 to 14.5 volts and should stay there unless there is a heavy load on the electrical system such as wipers, lights, heater and rear defogger all operating together while the engine is idling at which time the voltage may drop. If the voltage drops below 12.5, it means that the battery is providing some of the current. You may notice that your dash lights dim at this point. If this happens for an extended period, the battery will run down and may not have enough of a charge to start the car after shutting it off.  This should never happen with a healthy charging system because as soon as you step on the gas, the charging system will recharge the battery.  If the voltage is constantly below 14 volts, you should have the system checked. If the voltage ever goes above 15 volts, there is a problem with the voltage regulator. Have the system checked as soon as possible as this “overcharging” condition can cause damage to your electrical system.

Typical Ammeter – If you think of electricity as water, voltage is like water pressure, whereas amperage is like the volume of water.  If you increase pressure, then more water will flow through a given size pipe, but if you increase the size of the pipe, more water will flow at a lower pressure.  An ammeter will read from a negative amperage when the battery is providing most of the current thereby depleting itself, to a positive amperage if most of the current is coming from the charging system.  If the battery is fully charged and there is minimal electrical demand, then the ammeter should read close to zero, but should always be on the positive side of zero. It is normal for the ammeter to read a high positive amperage in order to recharge the battery after starting, but it should taper off in a few minutes.  If it continues to read more than 10 or 20 amps even though the lights, wipers and other electrical devices are turned off, you may have a weak battery and should have it checked.

What can go wrong?

There are a number of things that can go wrong with a charging system:

*Insufficient Charging Output
If one of the three stator windings failed, the alternator would still charge, but only at two thirds of its normal output.  Since an alternator is designed to handle all the power that is needed under heavy load conditions, you may never know that there is a problem with the unit.  It might only become apparent on a dark, cold rainy night when the lights, heater, windshield wipers and possible the seat heaters and rear defroster are all on at once that you may notice the lights start to dim as you slow down.  If two sets of windings failed, you will probably notice it a lot sooner

It is more common for one or more of the six diodes in the rectifier to fail.  If a diode burns out and opens one of the circuits, you would see the same problem as if one of the windings had failed.  The alternator will run at a reduced output.  However, if one of the diodes were to short out and allow current to pass in either direction, other problems will occur.  A shorted diode will allow AC current to pass through to the automobile’s electrical system which can cause problems with the computerized sensors and processors.  This condition can cause the car to act unpredictably and cause all kinds of problems.

*Too much voltage
A voltage regulator is designed to limit the voltage output of an alternator to 14.5 volts or less to protect the vehicle’s electrical system.  If the regulator malfunctions and allows uncontrolled voltage to be released, you will see bulbs and other electrical components begin to fail.  This is a dangerous and potentially costly problem.  Fortunately, this type of failure is very rare.  Most failures cause a reduction of voltage or amperage.

*Noise
Since the rotor is always spinning while the engine is running, there needs to be bearings to support the shaft and allow it to spin freely.  If one of those bearings were to fail, you will hear a grinding noise coming from the alternator.  A mechanic’s stethoscope can be used to confirm which of the spinning components driven by the serpentine belt is making the noise.
Repairing Charging System Problems

The most common repair is the replacement of the alternator with a new or rebuilt one.  A properly rebuilt alternator is as good as a new alternator and can cost hundreds less than purchasing a brand new one.

Labor time to replace an alternator is typically under an hour unless your alternator is in a hard to access location.  Most alternators are easily accessible and visible on the top of the engine.

Replacing an alternator is usually an easy task for a backyard mechanic and rebuilt alternators are readily available for most vehicles at the local auto parts store.  The most important task for the do-it-yourselfer is to be careful not to short anything out.  ALWAYS DISCONNECT THE BATTERY BEFORE REPLACING AN ALTERNATOR.

Alternators can be repaired by a knowledgeable technician, but in most cases, it is not economical to do this.  Also, since the rest of the alternator is not touched, a repair job is usually not guaranteed.

In some cases, if the problem is diagnosed as a bad voltage regulator, the regulator can be replaced without springing for a complete rebuild.  The problem with this is that there will be an extra labor charge for disassembling the alternator in order to get to the internal regulator.  That extra cost, along with the cost of the replacement regulator, will bring the total cost close to the cost of a complete (and guaranteed) rebuilt.

This is not the case when the regulator is not inside the alternator.  In those cases, the usual practice is to just replace the part that is bad.

This content is provided to you by All Makes Automotive Services.

All-Makes is the place to go for all your auto repair needs in Rio Rancho, NM.

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