headers install - open loop now?
05-17-2004, 06:05 PM
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headers install - open loop now? I installed LGM's LT headers on my 04 vette this weekend. Everything went as planned, I went with the straight throughs to the catback, so I'm running catless now. I've routed all of the front o2 sims out of the way of the headers, deleted the rear o2 codes with HPtuners etc. Basically did everything right (IMO, at least).
But now there seems to be a small problem.
I'm getting readings from the front o2's from anywhere between 500 and 900 mv, but it seems like the car never goes into closed loop running. My LTFT's and STFT's just sit there at 0. I can tell the car is running very rich, is it possible that it's running rich beyond the front o2 sensors capabilities?
The car runs well other than that, but it pops quite a bit on decel and the idle varies between 700-900 at times, but mostly idles smoothly. Any ideas?
But now there seems to be a small problem.
I'm getting readings from the front o2's from anywhere between 500 and 900 mv, but it seems like the car never goes into closed loop running. My LTFT's and STFT's just sit there at 0. I can tell the car is running very rich, is it possible that it's running rich beyond the front o2 sensors capabilities?
The car runs well other than that, but it pops quite a bit on decel and the idle varies between 700-900 at times, but mostly idles smoothly. Any ideas?
05-17-2004, 09:56 PM
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You stated FRONT O2 sims,
if that is true then thats the cause for the sims IF used would only be in replacement of using rear O2s location.
Due to the lousy placement of the front O2s on LGs, you need to use rear O2s due to their wire length but replace their connectors with the same as the fronts use.
In some cases I find people still use the front O2s and use some long wired coupler which uses normal wires where the O2s require outside reference air that is gotten via the air channel in the special wires O2s have.
Being your saying they never read under .500 mVolts to .900 says either O2s are being fooled its that rich, is tuned incorrectly, one of the sensors like water temp got wacked in header install or some type of leak.
With engine running yank wire connector to like injector for piston 1, your fuel trims via scanner should instantly go high positive or if you have an Ease scanner use bi-directional and it allows you to add or remove fuel to an injector and also allows just fuel trims to be reset and then see that LTFT and STFT values should be quickly moving around since PCM is relearning trim averages again.
if that is true then thats the cause for the sims IF used would only be in replacement of using rear O2s location.
Due to the lousy placement of the front O2s on LGs, you need to use rear O2s due to their wire length but replace their connectors with the same as the fronts use.
In some cases I find people still use the front O2s and use some long wired coupler which uses normal wires where the O2s require outside reference air that is gotten via the air channel in the special wires O2s have.
Being your saying they never read under .500 mVolts to .900 says either O2s are being fooled its that rich, is tuned incorrectly, one of the sensors like water temp got wacked in header install or some type of leak.
With engine running yank wire connector to like injector for piston 1, your fuel trims via scanner should instantly go high positive or if you have an Ease scanner use bi-directional and it allows you to add or remove fuel to an injector and also allows just fuel trims to be reset and then see that LTFT and STFT values should be quickly moving around since PCM is relearning trim averages again.
05-17-2004, 11:14 PM
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Guys, thanks for all the help, but this one solved itself with some driving time.
I drove the car to work today and hooked back up for some scanning tonight - looks like my LTFT's are reading again, albeit somewhat rich (Which I have taken care of now). Must of been PCM relearn or something..Whatever it was, I'm happy, and my LTFT's are locked down again
I drove the car to work today and hooked back up for some scanning tonight - looks like my LTFT's are reading again, albeit somewhat rich (Which I have taken care of now). Must of been PCM relearn or something..Whatever it was, I'm happy, and my LTFT's are locked down again