Ignition Timing Symptomsby Paul Novak
Ignition timing plays a critical role in the efficient operation of an engine. In order for the engine to properly burn fuel, the fuel must be ignited at the proper moment during the combustion cycle. If the ignition timing becomes out of synch, the fuel-and-air mixture will not be burned properly. This can result in several symptoms that vary in severity and can affect everything from drivability to fuel economy.
Pinging or knocking indicates that pre-ignition is taking place. Pre-ignition occurs when the fuel mixture in the engine's cylinder is ignited too soon and the piston has not completed its compression stroke. This causes the fuel and air mixture to ignite and push back against a piston as it is still trying to compress the fuel and air mixture. Timing that is too far advanced will ignite the fuel and air mixture too soon and will cause pre-ignition.
In order for an engine to start, the fuel and air mixture must be ignited within the cylinders at the proper time. If ignition timing is incorrect and causes the spark plugs to fire too soon or too late, the fuel-and-air mixture will not be ignited at the proper time which will cause the engine to become difficult to start.
If ignition timing is too far advanced, it will cause the fuel-and-air mixture to ignite too early in the combustion cycle. This can cause the amount of heat generated by the combustion process to increase and lead to overheating of the engine.
If the ignition timing is too far retarded it will cause the spark plug to ignite the fuel-and-air mixture too late in the combustion cycle. This results in the fuel-and-air mixture not being fully burning and ignition taking place after the piston has already begun moving downwards in its cylinder on the power stroke of the combustion cycle. The end result is a loss of engine power.
Increased Fuel Consumption
Incorrect timing will cause the fuel-and-air mixture to ignite at the wrong time within the cylinders. This results in the fuel-and-air mixture not being completely burned and a reduction in engine power. This poor combustion and reduced power causes the engine to use more fuel to produce enough power to propel the vehicle forward, which results in increased fuel consumption and reduced fuel economy.
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