Your engine needs proper ignition timing to ignite the fuel at, exactly the right time.
So, what happens if the ignition system fires, at the wrong time.
As a result, most of the time, power will fall while, fuel consumption and emissions will increase.
This is where proper ignition timing comes into play. You start off with fuel, air, compression and spark. But, for all that to work properly, the spark has to fire at the proper time. Only then, will the air-fuel mixture burn completely.
The way we measure this, is in degrees. This is always before or after, the piston reaches the top dead center (TDC).
Consequently, this measurement is better known as, advanced or retarded timing.
If the spark ignites the fuel, before the piston reaches (TDC); the ignition timing is said to be advanced.
If the spark ignites the fuel, after the piston reaches (TDC); the ignition timing is said to be retarded.
Manual Ignition Timing
This started out in most older engines. They used either vacuum advances or centrifugal advances, to set the right advance timing.
Whereas, modern engines have the Engine Control Unit (ECU) to dictate the advance needed, at a given engine speed.
Using A Vacuum Gauge To Test For, Incorrect Timing
Incorrect ignition timing, also affects manifold vacuum readings.
So, by connecting a vacuum gauge to a strong manifold vacuum source, lower than normal readings could indicate, incorrect timing.
Computerized Ignition Timing
Newer engines typically use computerized ignition systems. The computer has a timing map with spark advance values for all combinations of, engine speed and load. As a result, the computer will send a signal to the ignition coil at the indicated time; in the timing map.
Electronic Spark Control Module
Many people will also call this, the (ESC) module or the ignition module. The ignition module works together with the computer to set the engine’s ignition system; for the best performance and efficiency. As a result, one of the specific functions of the (ESC) module is to; advance or retard the timing of the ignition system.
Under heavy load, the module will advance the timing to increase power and will, retard it at low throttle. Furthermore, the (ESC) module makes these changes automatically and smoothly. Almost, to the point where they are virtually unnoticeable. So, the (ESC) module plays an important role in the operation of the engine. As a result, any problems with it can cause issues with; the drivability and performance in your engine.
What Can Happen With Incorrect, Ignition Timing:
Incorrect ignition timing, can cause several engine problems such as:
- Knocking or Pinging
- Difficult Starting
- Excessive Engine Heat
- Increased Fuel Consumption
- Reduced Power Output
Knocking or Pinging
Above all, this is one of the most common symptoms of, incorrect ignition timing. In these cases, the spark fires when the engine is still in its, compression phase. So, to prevent engine knocking, modern engines use knock sensors.
This can be either due to a advanced or delayed ignition. But, in both cases, the engine will not produce the optimal power; causing the vehicle to experience difficulty while starting.
Excessive Engine Heat
Igniting the air-fuel mixture too early in the power stroke can cause this.
This causes the engine to generate, more heat than usual.
Increased Fuel Consumption
Consequently, if the spark fires at the wrong time, it will result in improper combustion. This will also cause, the fuel economy to suffer.
Reduced Power Output
If the spark fires late, the piston is already on the way down, generating less power and wasting fuel.
There Are Three Distinct Types Of, Ignition Systems:
- The Mechanical Ignition System ( No Electronics )
- The Electronic Ignition System ( The Transition System )
- Distributorless Ignition System (DIS) ( No Moving Parts )
As you can see, there have been great advances over the years.
So, newer engines adjust the timing themselves; so as long as your sensors are all functioning as they should; you won’t have to do any tinkering with timing. In fact, you usually can’t unless you remap your ignition computer’s chip; or buy an aftermarket performance chip; that has a different timing map flashed into it. Be careful because the wrong chip can not only make your car run badly; but can also throw error codes and bring on the dreaded, check engine light.
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