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MAF at idle and spark timing rich condition

  • BrunoPecego
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3 years 1 month ago #57707 by BrunoPecego
MAF at idle and spark timing rich condition was created by BrunoPecego
1997 s10 4.3 Spark timing is negative 19 at idle so that should make my RPM lower than normal. To compensate for that, my IAC valve is open more than it should causing the MAF to read this extra air (8g/s instead of 4). Unfortunately my scan tool doesnt show me IAC counts to confirm. Is this possible? Maybe caused by worn distr. gear. What else would cause negative spark timing?

Rich condition around -30STFT and -18LTFT might have other contributing factor like old injectors that have worn spheres by someone trying to clean it. It is not leaking because fuel pressure does not drop. How can I confirm injectors spraying extra fuel?

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