what can cause a lean condition besides tune
06-16-2012, 01:05 PM
#1
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what can cause a lean condition besides tune so i just installed my new wideband, tr55 plugs and msd wires and went for a lil test drive and my afr at part throttle is about 14.7-15.0 right where it should be but my wot afr is 14.3ish. it seemed like it didnt even change or maybe the pcm is going into closed loop idk. can somebody help me out here.
here is a vid i made showing what the readings are
here is a vid i made showing what the readings are
06-17-2012, 04:16 PM
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probably tuning issue if its still on 14.7
even if you have small injectors or small fuel pump ,, it should jump to Rich then lean up
so i guess its a Tuning issue
unless you an issue with your Wideband
even if you have small injectors or small fuel pump ,, it should jump to Rich then lean up
so i guess its a Tuning issue
unless you an issue with your Wideband
06-17-2012, 07:05 PM
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Wondering if you're not hitting WOT completely. It seems like it's still correcting to run at stoich (normal for anything other than WOT.)
I have my car set to run at stoich at anything other than WOT once it's warmed up. But with PE on WOT, it goes to 12.5. Cheap and easy first, check your TPS and TB to see if you're going to full WOT. If your PCM doesn't see 100% throttle, it won't go into enrichment.
I notice you said "full bolt ons." Stock TB? LS1 or LS6 intake? Bump stop mod done to the TB? If not, there's your problem.
http://www.installuniversity.com/ls1...-stop-mod.html
I have my car set to run at stoich at anything other than WOT once it's warmed up. But with PE on WOT, it goes to 12.5. Cheap and easy first, check your TPS and TB to see if you're going to full WOT. If your PCM doesn't see 100% throttle, it won't go into enrichment.
I notice you said "full bolt ons." Stock TB? LS1 or LS6 intake? Bump stop mod done to the TB? If not, there's your problem.
http://www.installuniversity.com/ls1...-stop-mod.html
Last edited by bayer-z28; 06-17-2012 at 08:48 PM.
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06-17-2012, 11:17 PM
#10
EDIT: After reading more posts...I agree its probably the tune.
Last edited by minytrker; 06-17-2012 at 11:53 PM. Reason: edit
06-17-2012, 11:22 PM
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to the guys bitchin cause i dont have hpt **** you. if i had hpt i wouldnt need to ask this question i could look at it an tell myself. iv built my car from the ground up an have all the tools and no how to completely tare my car apart an put it back together, i know this because iv tore a f-body apart and built one of the nicest cars on this forum. i was just wondering if there is any sensors i could check (i can get things like a maf from my buddys car to see if it still reads the same)out and see if there bad until i can get up with my buddy that has hpt.
to the guys actually trying to help me thank you.
bayer- it has a ls6 intake with a stock tb that i ported and polished a lil bit. i did not get anywhere close to the blade all i really did is take the edges out of it an smooth it out a lil and then polish it. i did not do the bump stop mod.
i think it is a problem with the tune myself. when i switched over to a t-56 i had my buddy flash my pcm over to a m6 os, but he just used a tune from his car when he was bolt ons like me and then we did a wot run and was reading 13.6 aft through the narrow bands with no knock or anything so we called it good and never thought about it until i noticed i was getting terrible gas mileage (around 270 a tank or 18mpg) and i drive mostly highway 20 miles one way to work. so i did all the normal things to fix the bad gas millage issue, replace fuel filter, plugs, clean maf, tb, and ran some sea foam threw it and nothing helped so i bought the wideband and new tr55's and msd wires, and this is where we sit now until i can meet up with my buddy and look at what the car is doing.
if i was getting 14.3 afr at wot this whole time shouldn't i have blown im engine by now, i go wot at least once every day.
to the guys actually trying to help me thank you.
bayer- it has a ls6 intake with a stock tb that i ported and polished a lil bit. i did not get anywhere close to the blade all i really did is take the edges out of it an smooth it out a lil and then polish it. i did not do the bump stop mod.
i think it is a problem with the tune myself. when i switched over to a t-56 i had my buddy flash my pcm over to a m6 os, but he just used a tune from his car when he was bolt ons like me and then we did a wot run and was reading 13.6 aft through the narrow bands with no knock or anything so we called it good and never thought about it until i noticed i was getting terrible gas mileage (around 270 a tank or 18mpg) and i drive mostly highway 20 miles one way to work. so i did all the normal things to fix the bad gas millage issue, replace fuel filter, plugs, clean maf, tb, and ran some sea foam threw it and nothing helped so i bought the wideband and new tr55's and msd wires, and this is where we sit now until i can meet up with my buddy and look at what the car is doing.
if i was getting 14.3 afr at wot this whole time shouldn't i have blown im engine by now, i go wot at least once every day.
06-17-2012, 11:40 PM
#12
this is the PCM Diagnostic and Tuning section, hard to diagnose PCM Diagnostics and Tuning without proper information..but anyway
was your friends' car the same year? 2000 for instance got smaller injectors so if you flashed a 2002 tune that'll be way off, etc.
was your friends' car the same year? 2000 for instance got smaller injectors so if you flashed a 2002 tune that'll be way off, etc.
06-17-2012, 11:52 PM
#13
First problem is just loading your buddy's tune and not actually getting your car tuned. If it was that easy then there would be no point in a custom tune. Without tuning software to data log or a advanced scan tool you will just be guessing and parts swapping. There are to many variables to know if your engine would have blown being that lean all the time. It probably is that lean being you haven't actually tuned your car.
06-18-2012, 05:31 AM
#14
06-18-2012, 03:10 PM
#17
I don't see anybody specifying HPT except you. Scanning (not tuning necessarily) is a basic requirement of diagnosing a computer-controlled engine, so if you're going to work on your car yourself it's a good investment.
Maybe shop around for a used AutoTap or old EFILive scan-only kit for cheap, it will pay for itself in shop labor avoided.
edit: or for $50 or so get a universal scanner cable like these: http://www.scantool.net/
So with all your massive "...I no how to completely tare my car apart an put it back together..." skill, you can't diagnose it sitting in front of you...but you think people here can do so? Reality check dude.
It's possible that your narrowband sensor(s) feeding the gauge are simply reporting errors, because they are only built to switch at stoich. You need a wideband O2 sensor if you want accurate air:fuel ratio data.
Maybe shop around for a used AutoTap or old EFILive scan-only kit for cheap, it will pay for itself in shop labor avoided.
edit: or for $50 or so get a universal scanner cable like these: http://www.scantool.net/
It's possible that your narrowband sensor(s) feeding the gauge are simply reporting errors, because they are only built to switch at stoich. You need a wideband O2 sensor if you want accurate air:fuel ratio data.
06-18-2012, 04:12 PM
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i have a innovate wideband, that is what the video is of. the thing about the car not going into closed loop makes since but i will have to wait and see till i can get my buddys hpt. i was just looking for some feed back on what sensors can be causing the issue so i can start looking into it in the mean time.
06-18-2012, 04:36 PM
#19
Well the tune is a stock M6 tune from a 2000 car so I doubt that the tune is off. I turned off basic codes, speed limiter, fans, fuel cutoff and that is pretty much it. The car will be looked at hopefully this weekend as I live a hour away and have been working on my car everyday to finish it along with another car that I am building.
06-18-2012, 04:53 PM
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thanks bill, just so you know im not blaming this on you, i never asked you to actually tune the car, just to swap it over to a m6 so it would run right. thanks for helping me out.