* Engine speed (RPM): The timing advances at higher RPMs for better power and efficiency.
* Engine load: Heavier loads (like accelerating uphill) may require different timing.
* Engine temperature: The ECM adjusts timing based on the engine's operating temperature.
* Sensor inputs: Various sensors (like the oxygen sensor) provide data that the ECM uses to determine optimal timing.
Therefore, there's no single "correct" number. You'll find widely varying numbers online, and those are likely *base timing* values or values achieved under very specific conditions which may not be relevant to your car's actual running state.
Instead of searching for a specific timing number, you should:
1. Consult your vehicle's repair manual: This will give you the procedure for checking the base timing (the timing setting with the engine running at idle and certain conditions met). Even then, this is just a starting point for diagnosing problems and wouldn't be the *actual* timing under various driving situations.
2. Use a professional scan tool: A scan tool capable of reading the data from your car's ECM will provide the actual dynamic timing values under different operating conditions. This is the best way to assess if your ignition timing is correct.
Trying to adjust the timing yourself without understanding the ECM's role can seriously damage your engine. If you suspect an ignition timing issue, it's best to have a qualified mechanic diagnose and repair the problem.
