Flyboygsxr
ADAM
Is it better to run ethanol free gas? I have 93 octane here but there is also a station that is ethanol free.
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Shaun@AED said:At AED we recommend all our customers run Real Race Gas when on the road course. It's what we call 'cheap insurance'.
Mad Hatter said:Well after finding leaky weld on a repaired x-pipe just down flow from the rear O2 sensor...... once the leak was fixed... all the engine codes vanished and power went up!! Very happy.
TMSBOSS said:I am curious if the broken pipe caused a severe lean condition or if the break caused a sensor reading falsely indicating a severe lean condition??
twistedneck said:I thought I read Shaun said since the sensor was reading improperly due to the crack leak, the ECU tests it and then ignores that entire mechanism / sensor for controlling AFR an runs a closed loop type system i.e. it does not correct AFR via the long and short trims to get the measured lambda back to the commanded.
Instead, it survives by retarding the shiznit out of the timing and richening up at WOT via the feedback from high exhaust temperatures. Both of those things are not present on the track key but are there on the stock tune. Hence the engine survived!
O2 sensor measuring wrong during the ECU test, that sensor is ignored.
As uncorrected AFR gets lean, you start to see knock
Knock gets corrected by pulling up to 15 degrees of timing.
pulling all that timing cranks the exhaust temps through the roof - resulting in the stock tune's mega rich safety correction strategy.
Also, even if it does not knock, the lean condition will create high enough exhaust temps to engage the rich strategy.