Running Lean
06-19-2006, 05:30 PM
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Running Lean LT'S and ORY + new wires, AC DELCO IRIDIUM plugs, 13111 bosch 02 sensors, have air and egr hooked up...02 sims for rear...got scanned..both banks running a little LEAN...thought I should be running RICH...it even smells like I am rich.?? WHAT GIVES ??? ..........
06-19-2006, 06:29 PM
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Originally Posted by brad8266
What parameter did you scan to determine you are running rich?
06-19-2006, 08:43 PM
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I ask because many times people say the car is running lean when it really isnt. That is because that is what fuel trimming in the PCM is for and they are based on oxygen sensor activity. When you add the headers, initially you may run a bit rich, but the PCM will learn it quickly and adjust the fuel trimming to maintain 14.7 AFR. The car will not run lean or rich, the PCM will adjust to keep it at 14.7.
If you are really running rich then there is a problem such as an intake vacuum leak, fueling problem, or sensor problem.
If you are really running rich then there is a problem such as an intake vacuum leak, fueling problem, or sensor problem.
06-19-2006, 09:19 PM
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Originally Posted by brad8266
I ask because many times people say the car is running lean when it really isnt. That is because that is what fuel trimming in the PCM is for and they are based on oxygen sensor activity. When you add the headers, initially you may run a bit rich, but the PCM will learn it quickly and adjust the fuel trimming to maintain 14.7 AFR. The car will not run lean or rich, the PCM will adjust to keep it at 14.7.
If you are really running rich then there is a problem such as an intake vacuum leak, fueling problem, or sensor problem.
If you are really running rich then there is a problem such as an intake vacuum leak, fueling problem, or sensor problem.
06-19-2006, 09:23 PM
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Originally Posted by NHRAMAN
OK...will check these...will getting my injectors/fuel system cleaned help..I would hear an intake leak wouldn't I ?? have not touched intake. ..sensor problem?? I just installed new 13111 02 sensors...any advice is welcome..
Getting the fuel system cleaned will help if it is clogged up, which can happen to our rails since they dont have a return back to the tank. I would run some seafoam through the gas tank and replace the fuel filter first. An intake leak you can usually hear and usually the idle RPM will go up a bit with a decent leak.
Get that oxygen sensor issue checked first.
Last edited by brad8266; 06-19-2006 at 09:32 PM.
06-19-2006, 09:31 PM
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Originally Posted by brad8266
Getting the fuel system cleaned will help if it is clogged up, which can happen to our rails since they dont have a return back to the tank. I would run some seafoam through the gas tank and replace the fuel filter first. An intake leak you can usually hear and usually the idle RPM will go up a bit with a decent leak. Since you havent messed with anything really I would think you might just need the fuel system cleaned.
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06-19-2006, 09:47 PM
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Originally Posted by brad8266
Autozone and Advance Auto show 13444 to be the right oxygen sensor for your car, not 13111. Maybe thats a problem, although I know others use 13111 also.
Getting the fuel system cleaned will help if it is clogged up, which can happen to our rails since they dont have a return back to the tank. I would run some seafoam through the gas tank and replace the fuel filter first. An intake leak you can usually hear and usually the idle RPM will go up a bit with a decent leak.
Get that oxygen sensor issue checked first.
Getting the fuel system cleaned will help if it is clogged up, which can happen to our rails since they dont have a return back to the tank. I would run some seafoam through the gas tank and replace the fuel filter first. An intake leak you can usually hear and usually the idle RPM will go up a bit with a decent leak.
Get that oxygen sensor issue checked first.
06-19-2006, 09:50 PM
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Originally Posted by NHRAMAN
13444 ???? I have the wrong sensor ??? ..everyone told me 13111.
06-19-2006, 09:54 PM
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Very common after installing LT's. Airflow characteristics are much different and the O2 sensors are now farther from the heat. The PCM will trim, but not truly learn how to make up the difference. A tune sometimes is your best bet.
06-19-2006, 09:55 PM
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THANKS both of you...BTW...Anybody having trouble when they click 'New Posts' ???? I just get yesterday and before ??
06-19-2006, 10:05 PM
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Originally Posted by technical
Very common after installing LT's. Airflow characteristics are much different and the O2 sensors are now farther from the heat. The PCM will trim, but not truly learn how to make up the difference. A tune sometimes is your best bet.
06-20-2006, 02:54 PM
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Originally Posted by brad8266
Good point! They sensors will be a little scewed still since they arent as hot as they should really be due to them being down the exhaust stream so much. Yeah tuning is always the best way to go.
Which is why people told him to get the Bosch 13111 02 sensors (vette rears), they have a hotter sensor element.
06-20-2006, 02:58 PM
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Originally Posted by Roarin_8
Which is why people told him to get the Bosch 13111 02 sensors (vette rears), they have a hotter sensor element.
06-28-2006, 03:05 PM
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Check that you still have the EGR seal on the intake manifold pipe.
When I had my LTs installed the seal fell off the pipe and wasn't noticed. The care idled like crap and when I scanned it my STFT would go to + 15 - +20 at idle and the LTFT would then max at +25.
Without the seal on the EGR pipe you are introducing unmetered air into the fuel delivery system (after the MAF). I scanned it for DTCs as well and both banks had trouble codes for running lean.
I listened around and could hear a faint hissing around the EGR pipe. I threw a rag over it and the hissing noise reduced. After replacing the EGR seal and resetting the PCM it idles perfect and the STFT and LTFT are right back to normal.
When I had my LTs installed the seal fell off the pipe and wasn't noticed. The care idled like crap and when I scanned it my STFT would go to + 15 - +20 at idle and the LTFT would then max at +25.
Without the seal on the EGR pipe you are introducing unmetered air into the fuel delivery system (after the MAF). I scanned it for DTCs as well and both banks had trouble codes for running lean.
I listened around and could hear a faint hissing around the EGR pipe. I threw a rag over it and the hissing noise reduced. After replacing the EGR seal and resetting the PCM it idles perfect and the STFT and LTFT are right back to normal.
06-28-2006, 10:03 PM
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Originally Posted by beaSSt
Check that you still have the EGR seal on the intake manifold pipe.
When I had my LTs installed the seal fell off the pipe and wasn't noticed. The care idled like crap and when I scanned it my STFT would go to + 15 - +20 at idle and the LTFT would then max at +25.
Without the seal on the EGR pipe you are introducing unmetered air into the fuel delivery system (after the MAF). I scanned it for DTCs as well and both banks had trouble codes for running lean.
I listened around and could hear a faint hissing around the EGR pipe. I threw a rag over it and the hissing noise reduced. After replacing the EGR seal and resetting the PCM it idles perfect and the STFT and LTFT are right back to normal.
When I had my LTs installed the seal fell off the pipe and wasn't noticed. The care idled like crap and when I scanned it my STFT would go to + 15 - +20 at idle and the LTFT would then max at +25.
Without the seal on the EGR pipe you are introducing unmetered air into the fuel delivery system (after the MAF). I scanned it for DTCs as well and both banks had trouble codes for running lean.
I listened around and could hear a faint hissing around the EGR pipe. I threw a rag over it and the hissing noise reduced. After replacing the EGR seal and resetting the PCM it idles perfect and the STFT and LTFT are right back to normal.
