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99 saturn ignition timing

  • Bucher
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1 year 9 months ago #64340 by Bucher
99 saturn ignition timing was created by Bucher
1999 SL2 DOHC

Fuel trims go rich over 1000rpm (lean comand) but the opposite under 1000rpms.

I was originally looking potential weak spark as the issue but then I saw the advance timing.

Has anyone else seen these numbers with this engine? 

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1 year 9 months ago #64343 by Monde
Replied by Monde on topic 99 saturn ignition timing
Considering the RPM, the timing advance may be ok. What are the trims on bank 2?
Assuming is never a good thing.

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1 year 9 months ago #64349 by Bucher
Replied by Bucher on topic 99 saturn ignition timing
It's a 4 cylinder so I only have 1 bank. I'm still thinking it's weak ignition.

I tested 1 plug and the spark was strong but I'll have to check all of them. Idles okay so it's not a dead cylinder but maybe the spark is weak enough under load for the fuel trim to swing rich.

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  • Tyler
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1 year 9 months ago #64352 by Tyler
Replied by Tyler on topic 99 saturn ignition timing
An ignition misfire under load will cause lean trims, not rich. I'd be looking for a leaking fuel pressure regulator or an inaccurate MAP sensor.

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