Monday, July 19, 2010

Sparkplug Wires

The spark plug wires in your vehicle are designed to be strong and last for a long period of time. However, you should always keep an eye on the condition of the wires to make sure that your vehicle is receiving the correct amount of spark that it needs for proper functioning.

The wires are insulated and this is where the problems can occur. The insulation will keep the spark inside the engine and not outside where it can cause problems. Cracks in the insulation of the spark plug wires are an indication that the wires should be changed. A crack or break in the insulation will cause the spark to arc onto another metal area under your hood. The spark from the plugs will arc to these other areas and keep it from the engine where it belongs.

The cylinder that has a bad spark plug wire will receive a weak spark or in some cases, no spark. This will affect the way that your vehicle runs and you will notice that your car is running a bit rougher than normal. It will also affect the amount of fuel that your car is using. In some extreme cases, fuel can get into the exhaust system and affect the pollution control devices like the catalytic converter. Your spark plug wires that are arcing under the hood of your car can also be a dangerous situation if there is fuel in its vicinity.

Performing your own vehicle maintenance is a good way to ensure that your spark plug wires are thoroughly inspected. When it is time to change the spark plugs during a routine tune up, you should make sure that you give the spark plug wires a good inspection. This will save you a great deal of trouble down the road.

While you are under the hood of your car, begin at the distributor cap and follow the wire all the way back to the spark plug. Look for cracks and damage in the insulation of the spark plug wires. Turn the wires over and bend them slightly to expose any cracks that might not be visible on a first inspection. The part of the spark plug wires on the distributor end should be inspected as well for cracks and tears. Take the wire off of the spark plug to give the wires a good inspection. There may also be a burnt look to the wires that indicate damage as well.

Any damage that is found on your spark plug wires indicates that it is time to replace the wires. You will have to buy your wires in a set and they are usually pretty inexpensive to replace. Some wires may cost you more than others, but the savings that you will realize and the problems that are avoided make the higher cost on some wires very cost effective.

Performing routine maintenance on your vehicle, such as checking the spark plug wires, is an important part of making sure that your car is running as efficiently as possible. You can do most of these maintenance tasks on your own and save some money on auto repair bills. If you are not familiar with how to perform a tune up on your vehicle, there are many resources available to you online where you can learn how to give your car a tune up and take care of all the routine maintenance without having to set foot inside a repair shop.

Keeping your car running at its optimal performance will keep it running longer and also save you a great deal of money on fuel costs.

Ignition Coil

If you are an adult, chances are you own a car and drive it to work, the store, the shopping mall, grandma’s house, and many other places from day to day. Unless you are a mechanic or especially car minded, you probably do not think about all the processes that go into something as seemingly simple as starting your car up for all those long and short trips. In fact, probably the only time you think about the process of starting your car is in the rare and frustrating event that it doesn’t start up for you. Even if you don’t spend too much time thinking about how your car cranks, you probably should. Quite a bit of modern technology went into making the parts that start your car, and one of the main parts used in that process is the ignition coil.

Back before ignition coils were in common usage, cars started in what we today would see as a strange and alien way – they were started when the driver, standing outside, turned on the engine by turning a hand crank. Have you ever wondered why turning a car on is so often called “cranking the car?” Well, that is the reason. “Cranking the car” is one of the English language’s many antiquated terms that has happened to stick around long after actually manually cranking our cars fell by the wayside as a victim to newer and smarter technology.

Ignition coils, those handy devices that in part mean we no longer have to stand outside our cars and turn a hand crank when we are ready to drive to the corner store or shopping mall, are also called spark coils, because they help the power from the battery amplify into the thousands of volts of power that are needed to spark the spark plugs. The need for the ignition coil is simple. Car batteries only have 12 volts of power. (In fact, older car batteries may only have 6 volts.) But, a car’s spark plugs, the small devices that fit into the cylinder head of some internal combustion engines and cause the spark that lights the gasoline and causes internal combustion, need many thousands of volts of power in order to start (not crank, keep in mind) the car. The ignition coil’s job is to convert low voltage from the battery (remember, 12 or even as low as 6 volts) into those thousands of volts needed to start the car.

Even though ignition coils represent admittedly newer technology than those old hand cranks, they have been used in different ways in the past. Until recently, a car had only one ignition coil. That coil worked through a distributor, which, true to its name, distributed the volts amplified by the ignition coil to all the spark plugs. Newer car models though, eliminated the middle man so to speak, in that they eliminated the distributer. Instead, newer, distributor-less car models use many, much smaller ignition coils. These ignition coils server either one or two spark plugs and are electronically controlled. In modern cars, the ignition coils may be either remote mounted or placed on top of and in direct contact with the spark plug.

One important thing to know about modern ignition coils is that they put into motion the “wasted spark” system. When one ignition coil serves two spark plugs that single coil generates two sparks for each cycle it is powered. The only fuel that is ignited is the fuel in the cylinder that is nearing the end of its compression stroke. The other spark, then, is “wasted,” hence the name “wasted spark” system.

Distributor cap

The distributor cap is a critical device within you vehicle’s ignition system. Effectively, its purpose it to transfer the charge created by the rotating of the distributor shaft and the rest of the motor. The distributor cap takes that energy and uses it to power the engine’s cylinders at the appropriate time and order. As a critical portion of your ignition, it should be inspected whenever you’re having problems with the ignition, as well as on the pre-scheduled maintenance times, which can be found in your car’s manual. Distributor caps are pieces of your car that need to be fixed at certain times, and even if you find a problem in other components of the ignition system, there is a chance that your cap will need changing too.

hanging your distributor cap is a fairly easy job, and it can be done by somebody with even a low understanding of car parts or tool aptitude. It’s not as easy as unscrewing and re-screwing the cap, unfortunately, but it is a job that can be done with the most basic tool set, and one that can be completed in around an hour.

If you’re trying to check, remove or change your distributor cap (or the spark plugs), you’ll find it attached to any of the spark plug wires. These wires are located all around your engine, and should be easy enough to find. One end will be connected into the engine, and the other into the distributor cap, but it should look like it simply goes into a hole that is located near the engine. This is because you usually can’t just get to the distributor cap in most vehicles – normally, the air intake system will be in the way. You’ll probably have to remove the air intakes system, or at least some part of it, in order to get to the distributor cap.

Now, you probably won’t have to take off the entire air intake system, as the cap is fairly small, and should only be underneath one part of it. Nonetheless, removing any part of the air intake is going to be fairly easy, as it is bolted down. As long as you have a decent wrench, getting the bolts on should be no problem, although you’ll want to memorize what order you take the out in just in case. Once you unbolt the intake, it should pop right off, leaving the distributor cap uncovered. The plugs should be connected directly to it. In any case, it will be circular, facing sideways, and probably colored differently than the rest of your engine.

Before you detach the spark plugs, you’ll need to find some way of memorizing their appropriate spots. Each spark plug is attached to a cylinder on one end, and a corresponding slot on the distributor cap; whether you’re replacing a plug or the cap, you’ll need to make sure that the plugs maintain the same cylinder to cap position, otherwise, the cylinders that you’ve misplaced will no longer work.

Next, you’ll need to remove the spark plug wires and ignition cables. In some cars, you’ll have to remove other pieces of the engine in order to get to the ignition cables properly, but it shouldn’t be very hard to find out what that is and remove it. To remove the plugs, just twist and then pull them out. Remember to twist first! Otherwise you can damage the rubber cable, as it can stick to the plastic.

To remove the distributor cap, just unbolt it (or unscrew or unclip, as the case may be), take off any remaining wires, and slide the cap off the engine carefully (some parts of the engine that the cap is connected to are very fragile). To install a new cap, simply replace the rotor an cap, and then reverse your steps.

How to Install an Ignition Distributor

  1. Mark the position of the rotor prior to removal of the distributor. This will aid in installing the replacement unit into the proper position.
  2. Install the replacement distributor so the rotor points in the same place.
  3. Compare the original distributor to the replacement unit. Pay special attention to the area below the flange. Check all dimensions!
  4. Lubricate the o-ring before inserting the distributor into the engine to prevent bent pins.
  5. Be sure not to force the distributor into the engine or use a bolt to pull it into the block! Damage to the distributor and/or engine may occur.
  6. Inspect all components (spark plugs, wires, etc) in the ignition system for wear and/or corrosion. Replace as necessary.
  • The Ignition distributor is basically the heart of the ignition/spark system. The PCM,ECM, or vehicle computer is the brain and controls the distributor. The distributor is being removed form most late model vehicles and a direct ignition system is being installed. The direct ignition system basically supplies spark direclty to the spark plug rather then going through a distributor to distribute the spark. The distributor has many parts including moving mechanical parts and several electrical components that are subject to extreme engine conditions such as heat and extreme voltage that the ignition coil produces. Most late model vehicles that still use a distributor, can have 20-50,000 volts running through it. This voltage has to move from the coil, into and through the distributor and out through the spark plug wire and through the spark until it ignites inside the cylinder. Many times worn spark plugs and wires can back this voltage up into the distribtuor and/or ignition coil and cause it to short out and fail. Performing a tune up often(every few years) can prevent this from happening and can save or preserve the life of a distributor. Many other factors can cause a distributor to fail. These other factors include:
    • Worn or excessive play in the timing belt or chain

      Inserts,Gauges, Taps, Tools, Kits, Specialist Stockist / Distributor

      Leaking o-ring at the base of the distributor
    • High resistance in the spark plug wires or spark plugs
    • Worn Distributor cap, rotor, or other worn ignition components.
  • If you have a failed distributor or ignition coil, it is strongly recommended to replace the other related tune up components. Putting a brand new distributor or coil on a vehicle with old or worn spark plug wires and old/worn spark plugs is simply silly and will most likely cause you to replace the same parts over again. Look closely at the ignition system as a whole and most likely a good tune up is due when a distributor or coil failure happens.

Top Dead Centre (TDC) and ignition timing

When a piston in an engine reaches the top of its travel, that point is known as Top Dead Centre or TDC. This is important to know because I don't think any engine actually fires the spark plug with the pistons at TDC. More often than not, they fire slightly before TDC. So how does your ignition system work, and what is ignition timing all about?

Well generating the spark is the easy part. The electrical system in your car supplies voltage to your coil and ignition unit. The engine will have a trigger for each cylinder, be it a mechanical trigger (points), electronic module or crank trigger. Whatever it is, at that point, the engine effectively sends a signal to the coil to discharge into the high voltage system. That charge travels into the distributor cap and is routed to the relevant spark plug where it is turned into a spark. The key to this, though, is the timing of the spark in relation to the position of the piston in the cylinder. Hence ignition timing. Having the spark ignite the fuel-air mixture too soon is basically the same as detonation and is bad for all the mechanical components of your engine. Having the spark come along too late will cause it to try to ignite the fuel-air mixture after the piston has already started to recede down the cylinder, which is inefficient and loses power.
Timing the spark nowadays is usually done with the engine management system. It measures airflow, ambient temperature, takes input from knock sensors and literally dozens of sensors all over the engine. It then has an ignition timing map built into its memory and it cross references the input from all the sensors to determine the precise time that it should fire the spark plug, based on the ignition timing map. At 3000rpm, in a 4 cylinder engine, it does this about 100 times a second. In older systems, the spark timing was done using simple mechanical systems which had nowhere near the ability to compensate for the all the variables involved in a running combustion engine.
Typically as an engine revs quicker, the ignition timing needs to advance because the spark needs to get to the cylinder more quickly. Why? Well the fuel-air mix takes a finite amount of time to combust. It won't burn any quicker or slower for any given engine speed. So for higher speeds, the mixture needs to be ignited earlier in the cycle to ensure that it begins to burn at the optimum timing point. In modern systems, this is all taken account of in the ignition timing map. On older mechanical system, they used mechanical or vacuum advance systems, so that the more vacuum generated in the intake manifold (due to the engine running quicker), the more advanced the timing became.

Checking ignition timing

timing mark

Despite the speed that an engine turns, it is possible for mere mortals like you and me to be able to check the ignition timing or an engine using (and you'd have never guessed this) an ignition timing light. Timing lights are typically strobe lights. They work by being connected to the battery directly and then having an induction coil clamped around one of the spark plug leads - normally the first or last cylinder in the engine depending on the manufacturer. When the engine fires the spark plug for that cylinder, the inductive loop detects the current in the wire and flashes the strobe in the timing light once. So if the engine is ticking over at 1100rpm, the strobe will flash 550 times a minute (4 stroke engine, remember?). Fantastic. So you're now holding a portable rave lighting rig but how does this help you see the timing of an engine? Well it's simple. You must have seen strobe lights working somewhere - a rave, a stage show - they're used to effectively freeze the position of something in time and space by illuminating it only at a certain point and for a fraction of a second. Shooting a strobe at someone walking in a dark room will result in you seeing them walk as if they were a flip-book animation on a reel of film. This effect is what's used to visualise the timing of your engine. Somewhere on the front of the engine there will be a notch near one of the timing belt pulleys and stamped into the metal next to it will be timing marks in degrees. On the pulley itself there will be a bump, recess or white-painted blob. When you point the timing light down towards the timing belt pulley, remember it fires once for each firing of the cylinders? Each time it fires, the white blob on the pulley should be at the same position in its rotation - the strobe fires once for each ignition spark at which point the mark should be in the same place, and the effect to you is that the whole pulley, timing mark and all, are now standing still in the strobe light. The mark on the pulley will line up with one of the degree marks stamped on the engine, so for example if the white dot always aligns with the 10° mark, it means your engine is firing at 10 degrees before TDC. When you rev the engine, the timing will change so the mark will move closer or further away from the TDC mark depending on how fast the engine is spinning.
Note that in some engines, the two marks are simply painted or stamped, and there are no degree markings. In this case, the marks align when the first piston is exactly at TDC.

Check the timing marks first

After all that, it's worth pointing out that crank timing marks can be way off so it's worth confirming that your TDC marker is actually TDC before pratting about with the timing. It's not as bad now as it used to be, but in the bad old days, Rover V8's were particularly bad for this, with some being as much as 12° off! So how you do confirm your TDC really is TDC? Small cameras, a good set of feeler gauges, some cash and someone who knows what they're doing.

Timing marks on cam belt pulleys

The same timing marks exist stamped into the metal near, and on the pulley on the end the cam. Essentially these marks are used to line up the cam to the correct position when you're changing the timing belt. You have to make sure the engine is rotated to TDC and that the cams are properly aligned too. If you don't, the cams will spin permanently out-of-synch with the engine crank and the engine will run badly, if at all.