Why am I running Lean??
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Joined: Sep 2002
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From: Minnesota
Why am I running Lean?? Hey guys I had my SS Dynoed to see what she had for power, I have LT Headers, X-Pipe, Lid, FTRA, And home ported TB. Well the car put down 340RWHP and 350RWTQ (NO TUNING) But my A/F was reading almost 17 to 1 which is very lean, Why would it do this, and how can I fix it? Also will tuning give me more RWHP and RWTQ?
Wow. Were they using a wide band o2 sensor on that dyno to get your a/f ratio? I'm not an expert, but it seems that the general consensus around here is in order to get an accurate a/f ratio after a LT header install you need a wide band o2. Relying on something like ATAP isn't a good idea because the placement of the o2's has moved and could be giving inaccurate readings.
To answer your question, I think there is def. more to be gained by rich-ening up your a/f mixture. And not just in the hp/tq dept either, you could damage some critical engine components running that lean.
To answer your question, I think there is def. more to be gained by rich-ening up your a/f mixture. And not just in the hp/tq dept either, you could damage some critical engine components running that lean.
Do you have the stock MAF with screen? If not that is one reason. Another is that you could have the crappy Hypertech tuning in there and not know it! Did you buy the car used?
Does it make popcorn sound?
Post your dyno graph with A/F if you could.
I wouldn't be doing to many WOT runs with that A/F or you'll be buying a new engine...
Does it make popcorn sound?
Post your dyno graph with A/F if you could.
I wouldn't be doing to many WOT runs with that A/F or you'll be buying a new engine...
Thread Starter
12 Second Club
Joined: Sep 2002
Posts: 547
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From: Minnesota
I bought the car used from the original owner, and it was totaly stock when I bought it. I did how ever remove the screen from the stock MAF, but did not do any porting. It does not make any popcorn sounds when running. How do I post the Dyno graph, I have a scanner so should I just scan it and post it up here or what do I do?
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Thread Starter
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From: Minnesota
It was a tailpipe wide band and I have a small exhaust leak right where my headers bolt to my exhaust, but very small leak you can bairly hear it. I tried to upload the dyno sheet and it said the file was to big? can I email it to some one and see if they can get it to work? I am not to good with computers 
Dan
Dan
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Joined: Apr 2003
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From: Atlanta, GA
Originally Posted by ONGRNGO
It was a tailpipe wide band and I have a small exhaust leak right where my headers bolt to my exhaust, but very small leak you can bairly hear it. I tried to upload the dyno sheet and it said the file was to big? can I email it to some one and see if they can get it to work? I am not to good with computers
Dan
Dan
Any exhaust leak will bump your A/F ratio up a bit depending on how bad the leak. If you can hear the leak it probably is pretty bad and will throw your A/F ratio off. The W/B sensors generally are pretty sensitive and to be honest if you are driving with a leaking exhaust you are definitely hurting your overall performance as your Narrowband sensors are sensitive as well and your PCM will always be trying to adjust for a false lean condition.
Thread Starter
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From: Minnesota
Originally Posted by HumpinSS
Does this hold tru if the leak is after the o2 sensors which seem to be the case
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From: Atlanta, GA
Originally Posted by ONGRNGO
Yeah how would it sense the leak if it was after the o2 Sensors, I have No cats so only running the front o2s.
I had a leak where my headers where clamped to my y-pipe using band clamp and it was ticking out the clamp. It made my passenger side LTRIM almost 10 points different than my driver side. It just depends on how close the O2 sensor is to the leak. Mine was about 5 inches and when I installed a new band clamp both where almost identical and the false lean condition disappeared. If your is way past your O2 sensor then it would explain your Wideband being off but it would not most likely affect your main O2 sensors.
