Hello all,
I have a pretty much one-off set up with my car and have been battling a lean condition on acceleration for a while now. First of all I will tell you about the car:
2001 Pontiac Firebird/Firehawk 38K miles
LS3 short block bored and stroked to a 429ci all forged internals etc.
Trick flow cathedral port heads (can't remember intake runner size off the top of my head)
Fast 102 intake and Nick Williams throttle body
Custom 4 inch intake tube with larger snouted intake box (don't know brand, had it on car when I bought it)
Custom ground Comp cam 238/243 duration at .050" lift, 112 LSA, .617" max lift..can't remember advertised duration
4l80e B&M Transmission with manual valve body
Moser 9" with pro comp center section
Fully adjustable suspension with tubular k member etc
N/A no boost or nitrous
Anyways, the car is currently running on speed density with the custom operating system installed. I have been vigorously calibrating the VE table, so it should be dialed in with LTFT's in the right neighborhood. So with that said, I started adjusting the transient fuel settings and adding to the fuel to wall impact factor, as well as the gain and the boiling time. This has gotten me in the right direction, but I am still seeing lean popping at acceleration and hearing popping randomly when crusing, but no lean condition indicated on my wideband in car. I started looking at my datalog more and saw that the o2 millivolts were getting really low, like in the 50s and 60s when this lean/popping condition is taking place. Then when the car comes out of it, the o2 sensors oscillate as normal. I understand the o2 sensors only measure oxygen in the exhaust, but I'm wondering if the sensors are actually ceasing to work (which usually would show 450 mlv from what I understand) and this is causing the lean condition, or if the o2 sensors are reading really low because of the lean condition. Now sometimes my STFTs kick up to 12% in these situations which would lead me to believe the o2 sensors are working properly, but when I actually look at the histogram the STFTs in those corresponding cells are not that high. So I'm chasing my tail here and definitely in need of any help I can get. Anyone have any advise? I'm including my calibration and config/scan files as well.
Thanks in advance!
transient 8.hptSpiking lean from takeoff 01 Firehawk.hpl