What Happens When the Ignition and Cam Timing Are Off?

Ignition and camshaft timing are important to the performance and longevity of vehicle engines. The engine will run smoothly when both timing values are properly adjusted. An engine can have varied degrees of performance problems when the ignition and cam timing are off.

Cam Timing

• Cam timing determines when the valves open and close with respect to the position of the pistons in the cylinder, controlling flow of fuel and exhaust. Exhaust manifolds or headers turning red while the engine is accelerating and overheating are symptoms of bad cam timing. The engine may also lose power.

Ignition Timing

• Poor ignition timing results in poor fuel economy and sluggish engine performance, such as loss of power. Overheating can occur when the ignition timing is retarded. Ignition timing determines when the spark plug will fire in the combustion chamber.

Timing adjustments

• Cam timing is set at the factory and cannot be adjusted on stock engines. Most automobile engines manufactured after 1990 have ignition timing set by an on-board computer. The computer adjusts the ignition timing automatically. Engines in cars older than 1990 have ignition timing set manually during maintenance service.