Your engine needs proper ignition timing, to ignite the fuel, at exactly the right time.
But, what happens if, the ignition system fires, at the wrong time.
Consequently, the fuel-and-air mixture, will not be burned properly. As a result, power will fall, while fuel consumption and emissions will increase.
Subsequently, this is where, proper ignition timing comes into play. So, you start off with fuel, air, compression and spark. But, for all that to work properly, the spark plug 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.
- So, if the spark ignites the fuel, before the piston reaches (TDC). Then, the ignition timing is said to be, advanced.
- However, if the spark ignites the fuel, after the piston reaches (TDC). Then, the ignition timing is said to be, retarded.
Manual, Ignition Timing
So, back in the day, most older engines had, manual ignition timing. Consequently, 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 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. And, is used for all combinations, of engine speed and load. Then, the computer will send a signal to the ignition coil, at the indicated time in the timing map.
Electronic Spark Control Module
Also, known as, the (ESC) module or the ignition module. So, the ignition control module, works together with the computer. And, is used to set the engine’s ignition system, for the best performance and efficiency. In other words, one of the specific functions of the (ESC) module. Consequently, is to advance or retard the timing of the ignition system.
So, under heavy load, the module will advance the timing. And, to increase power and will retard it, at low throttle. Meanwhile, 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 an advanced or delayed ignition. But, in both cases, the engine will not produce the optimal power. And, cause 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. In addition, 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 Basically, 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.
Consequently, newer engines adjust the ignition timing themselves. So, as long as your sensors are all functioning properly, you won’t have to do any tinkering with timing. In fact, you usually can’t, unless you remap your ignition computer’s chip. However, you can 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, it can also throw error codes and bring on the dreaded, check engine light.
Thank You !