NB O2's & Lean WOT
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
NB O2's & Lean WOT I've been running the same tune for over two years and had my AFR's dialed in pretty closely. Several weeks ago I went to the track for the first time in a year and a half. My times were off about 6 tenths and 7 mph. Since then, I've been able to determine that when I go WOT, my NB O2's initially peg to 850-950mv and then crater to 75-150mv and hold there. AFR's are in the 16-18:1 range when the NB readings are low. I'm lucky I haven't blown my engine!
I unplugged my MAF and logged and got the same behavior. MAF has been cleaned, fuel filter replaced, injector cleaner run, I have no apparent misfire, no DTC's, and the NB's seem to perform normally at part throttle. IBPW, Maffreq, INJDC all are normal. I should mention that I do have my O2 sensor DTC's turned off because of the usual low voltage/switching codes that occur with LT's.
Any suggestions??
I unplugged my MAF and logged and got the same behavior. MAF has been cleaned, fuel filter replaced, injector cleaner run, I have no apparent misfire, no DTC's, and the NB's seem to perform normally at part throttle. IBPW, Maffreq, INJDC all are normal. I should mention that I do have my O2 sensor DTC's turned off because of the usual low voltage/switching codes that occur with LT's.
Any suggestions??
What's WOT fuel pressure look like? This sounds like
what you'd get with the line at pressure, but without
the flow capacity to back it up. Filter, power quality,
that kind of thing?
But any misfiring will also spoof the NBO2s (or wideband)
to read lean.
what you'd get with the line at pressure, but without
the flow capacity to back it up. Filter, power quality,
that kind of thing?
But any misfiring will also spoof the NBO2s (or wideband)
to read lean.
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
I replaced the fuel filter in between the two logged runs, but without effect. It was a little clogged, but not extreme.
Haven't put a fuel pressure gauge on the car yet; I'm away from it for another week. I'm soliciting ideas at this point.
No perceptible misfires or DTC's ...
Haven't put a fuel pressure gauge on the car yet; I'm away from it for another week. I'm soliciting ideas at this point.
No perceptible misfires or DTC's ...
Thread Starter
Joined: Nov 2003
Posts: 6,216
Likes: 236
From: Wichita KS / Rancho San Diego
I had trouble getting my AFR's to report correctly after upgrading to a later 7.5 build. Basically, my LM-1 is set up like an LC-1 so the LM-1 pid is not used. Joecar set me up with the latest Calc.VET pids, so AFR is derived from a variety of calculated pids. Look at the pid selection on the 1118 log and you'll be able to see how the WB is reporting.
