why is it running lean?
04-17-2006, 11:59 AM
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why is it running lean? Had the car dynoed and it put down 328hp and 333tq. I thought that was kind of low with the mods that I have and stock tune. I was kind of worried also because the a/f was 13.6. I was told it makes more power when it runs lean but is there a point where running too lean hurts the power? I checked the fuel pressure and it was right at 60psi so I don't think the pump is going bad. What else would cause it to run lean? Bad o2 sensors?
04-17-2006, 02:17 PM
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Could be a number of things. When i put on my LT's my car ran like 14:1 lean. You need to get a tune and get that corrected. You won't pick up allot more HP but will see a few more ponies
04-17-2006, 03:10 PM
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The guys at the dyno said most of the LS1s they dyno put down 12.8 with LT. I don't want to tune it if there is still another problem. I just filled up and got my worse mpg ever at 13.4mpg. Think this has something to do with it also?
04-17-2006, 03:42 PM
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If you still have cats and they were sticking the A/F probe up the tail-pipe, then you're actually closer to 12.8 to 1 than 13.8 to 1. Cats and tailpipe probes commonly show leaner numbers than that are actually taking place. Not all tuners know this.
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04-17-2006, 04:37 PM
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Originally Posted by Patrick G
If you still have cats and they were sticking the A/F probe up the tail-pipe, then you're actually closer to 12.8 to 1 than 13.8 to 1. Cats and tailpipe probes commonly show leaner numbers than that are actually taking place. Not all tuners know this.
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04-17-2006, 04:50 PM
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Originally Posted by Optimus_Prime
Would getting just a GMMG catback cause the car to run lean?
04-17-2006, 07:27 PM
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for a mostly stock engine that is not lean. perfect is 14.7:1 for most engines. so running 13:1 is not going to hurt your engine it is actually running rich. it's when you get alot of mods that they richen up the a/f to get the most performance out of your mods.
04-18-2006, 06:25 PM
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Originally Posted by Mazzenger
The addition of LTs fattend mine to 12.5 to 1 with not cats.
That's what I have heard most of them are at with LT. That's why when mine is at 13.6 I think something is up with the car.
04-18-2006, 06:27 PM
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Originally Posted by 98NBMZ
Did Jason tune it or have you even had it tuned yet?
04-18-2006, 07:48 PM
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Originally Posted by Radcat
I don't have any cats.
04-18-2006, 07:55 PM
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Originally Posted by fguy1998
for a mostly stock engine that is not lean. perfect is 14.7:1 for most engines. so running 13:1 is not going to hurt your engine it is actually running rich. it's when you get alot of mods that they richen up the a/f to get the most performance out of your mods.
04-18-2006, 09:40 PM
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Originally Posted by fguy1998
for a mostly stock engine that is not lean. perfect is 14.7:1 for most engines. so running 13:1 is not going to hurt your engine it is actually running rich. it's when you get alot of mods that they richen up the a/f to get the most performance out of your mods.
wow, talk about getting bad info on the internet
also, 02 sensors have absolultely no effect on WOT a/f.
the only thing you need is a tune. part throttle and WOT. your part throttle tuning is causing your poor MPG. the best way to tune is on the street with a wideband. I would suggest doing that if possible.
04-19-2006, 12:15 AM
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Originally Posted by 383ss
also, 02 sensors have absolultely no effect on WOT a/f.
What makes me worry though is that I hear most ls1s with LT are around 12.8 or so and I'm quite a bit higher than that. Do you really think it's because of the stock tune or could it be something else? Do you think my stock pump could be going out(72k on it)?
04-19-2006, 05:49 PM
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My car with headers when it was untuned was at 12.0 across the board..
My stock pump has 104k on it with ZERO problems, if it was you would probably be able to tell because the car wouldn't run well at all.
Was you car going through the muffler on the dyno? (wideband in the tailpipe after the muffler)
My stock pump has 104k on it with ZERO problems, if it was you would probably be able to tell because the car wouldn't run well at all.
Was you car going through the muffler on the dyno? (wideband in the tailpipe after the muffler)
04-19-2006, 07:00 PM
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Originally Posted by Chris81
Was you car going through the muffler on the dyno? (wideband in the tailpipe after the muffler)