tinman
Boosting 20 psi
Posts: 87
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Post by tinman on Apr 17, 2010 13:10:38 GMT -5
something new here, sitting in the car playing with QH, and noticed my afr was falling the longer i let it idle, eventualy pegging at 10.0. if i drive it it goes back to 14-15 range for as long as i'm driving it, as soon as i come to a stop and idle for a few seconds it starts to fall again to 10.0 within a few seconds. i thought something in the QH or bin, so i switched back to the stock ecm and dissabled QH and it does the same thing.  |
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Post by Stinger on Apr 17, 2010 15:35:29 GMT -5
Sounds like the wideband reading wrong. Do you smell fuel when it does it? Does the engine try to die? They won't hardly idle at all when that rich.
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tinman
Boosting 20 psi
Posts: 87
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Post by tinman on Apr 17, 2010 19:31:07 GMT -5
i don't smell a lot of fuel, and it does keep running fairly well, not rough. maybe i need to put a few more miles on it and see how it does on a longer trip.
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Post by Stinger on Apr 17, 2010 20:09:10 GMT -5
What wideband setup is it?
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tinman
Boosting 20 psi
Posts: 87
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Post by tinman on Apr 18, 2010 8:59:58 GMT -5
the w b is an aem. this morning i reloaded a stock tune again, it seems ok idling at 14.5-15 afr. i noticed if you drive it easy not letting it spool at all, it stays 14ish, as soon as it starts to spool at all, it goes full rich instantly. as soon as you ease off a bit it goes to 14 ish again. i don't think it's the wb because it's not inconsistant. it will do this as long as you want, the same every time you push the accelerator. right now i have the intercooler bypassed,so i turned down the base fuel pressure to 34# and the boos ???t down to 8 psi. now when i drive it it seems normal, at full throttle and 8 psi afr stays at high 11s to low 12. do you suppose it has anything to do with a high base fuel pressure? |
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Post by Stinger on Apr 18, 2010 11:05:37 GMT -5
Well, if you have more fuel pressure than the engine requires then yes, the fuel pressure could cause a rich condition.
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tinman
Boosting 20 psi
Posts: 87
|
Post by tinman on Apr 18, 2010 15:15:31 GMT -5
well.. the fuel pressure has been high for a while, so i could get by with big boost , but it didn't act like this. since i bought the QH so i could do a mass air conversion ,i'll just go ahead and start on that and then go from there. thanks for your help.
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