Ignition Timing – Your Engine Knows Timing Is Everything

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.

Most of the time power will fall and gas consumption and emissions will increase.

Ignition Timing
Ignition Timing

This is where proper ignition timing comes into play.

You start off with fuel, air, compression and spark.

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).

This measurement is better know 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 Timing

Top Dead Center (TDC)
Top Dead Center (TDC)

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. Connect a vacuum gauge to a strong manifold vacuum source. Lower than normal readings could indicate incorrect timing.

Computerized 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. The computer will send a signal to the ignition coil at the indicated time in the timing map.

Electronic Spark Control Module

Electronic Spark Control Module
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. 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. 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

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. To prevent engine knocking, modern engines use knock sensors.

Difficult Starting

This can be either due to a advanced or delayed ignition. 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

Poor fuel economy
Poor fuel economy

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.

Ignition Timing-Conclusion

Finally, It is important that spark plugs fire at the proper time during a piston’s compression stroke.

So, Timing is everything.

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DannysEnginePortal.com Is The Premier Automotive Engine Troubleshooting Resource Site. DannysEnginePortal.com Shares Information On Engine Troubleshooting, Engine Rebuilding, Engine Repair Tips, Tech Info, Basic Machining, Automotive Testing, In Addition To Possible Solutions.