odd issue

[Dthreap]

tried searching to see if i could find something on this here but i couldn't so might as well post


removed rear o2 for wideband install since we just put headers on a 99 GP GT and egr is removed

deleted codes for both egr and o2 and getting maxed out LTFT and STFT at idle trying to seal the egr port on the lim and thinking that's the issue before i go into the tuning side of it... any suggestions for possible solutions would help because i know there is a diagnostic issue that makes the trims go positive Thanks in advance!

[Wingman520]

uploaded tune that is currently on the vehicle gonna try to unplug the maf and see if the trims will go negative to see if it's a vacuum leak haven't had a chance to scan it yet but when i did had a bad o2 sensor and replaced that today and still max ltft and stft

[MMGT1]

I would be looking for an exhaust leak before the #1 O2 sensor or around the #1 O2 bung itself. Have you tried using brake parts cleaner around the intake and connections to ensure it's not a vac leak yet?
From what you are saying, it sure looks to me like unmetered air is getting in there somewhere!

[Wingman520]

brand new headers installed not even two weeks ago and replaced the o2 with a brand new denso since the old one was soaked in radiator fluid from the good ol' lower intake gaskets going bad (common issue) so that's brand new

pulled the maf and set the code for the maf error to put it to run off of the other two sensors it uses when the maf fails (can't recall offhand since been up since 7 am yesterday) and to see if the trims would go negative to test for vaccum leaks and nothing... trims stayed positive the whole time... headers are slip fit and the exhaust from the downpipe back to the resonator connection is fully welded... wideband shows it's running the proper afr, but the trims stay max on LTFT and STFT gonna get a scan asap when my friend is free after i put the maf table back to stock and see if it does anything... no leaks through exhaust or the egr hole we plugged up and sealed but gonna double check that egr hole on the LIM as well to see if air is getting by it somehow.... rear o2 is removed fyi and codes are also but not sure how to tackle that since it's a 99 GPGT and i know it was 2000 or 2001 they put the new cat codes in that made you run the o2 simulator


i'll def try using brake parts cleaner but wouldn't that be dangerous since some brands are flammable? or will it just choke out?

[Wingman520]

scan uploaded showing the issue... fyi it was run on the current beta out for hpt and the wideband isn't hooked up so ignore those readings

[matt5112]

How did you seal the LIM?

Most end up using the flange from the EGR tube, a penny, and copper RTV. Typically works quite well.

Who's headers are you running? Are you using the stock O2 locations?