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Question is where would you start?.... I've fiddled around with voltage offsets, PRP gains/offsets, and nothing seems to really affect it. I really cant analyze the data well enough to understand what's going on.
I'm almost to the point where i would pay $$$ to someone who can help me fix this
What I'm seeing:
NB O2 - crosses at 1.5-2seconds at idle (not sure if this is enough oscillation?)
INT stays put for the most part
BLM follows the surge drops to 124 (before 650rpm) and jumps to 127 (after it goes up to 850rpm)
VE% appears to follow the O2 activity (O2 goes low, VE% goes up)
I uploaded the .dat file(zipped), .csv file of the idle, and the .bin file
Specs: 350/vortec heads/ zz4 hot cam / 1.6rockers
TPI (EBL P4/TT1 WB) - big tube/ported/larger Tbody
injectors Bosch III - 30lbs.(RED) 0280155759
Last edited by pfreer3; Jun 30, 2018 at 09:17 PM.
Reason: forgot some stuff...
Couple of items noticed in the log, the vehicle voltage is on the low side. Both pump and ignition are right around 12 volts and will even dip into the high 11 volt range. Should be higher with a running engine.
The IAC is open too far (60 - 80 steps). Turn in the idle stop screw to get the IAC step count in the 20 - 25 range. This is on a warm engine with no other loads.
Change this parameter to 1100 RPM:
BLM - Idle Cell RPM Threshold
It is currently at 800 RPM which is why the BLM value flips back and forth.
Also, on the VE table there is a dip right in the idle area (700 RPM, 55 KPa). Smooth that area out some, level it.
The engine is surging due to the AFR going lean. This causes the RPM to surge upwards where it gets richer. This causes the idle to settle down where it goes lean again. Rinse and repeat.
Well, you were spot on about the 11-12volts... went out this morning and tried to start the engine. Battery was drained, and with the key on, the alt was hot to the touch. Engine wouldn't turn over.
Pretty sure the Alt is shorted internally, but its too hot outside to work on until dark.
Did not see that one coming... Thanks!
One other question, does the sPW look too long for idle?
Well, you were spot on about the 11-12volts... went out this morning and tried to start the engine. Battery was drained, and with the key on, the alt was hot to the touch. Engine wouldn't turn over.
Pretty sure the Alt is shorted internally, but its too hot outside to work on until dark.
Did not see that one coming... Thanks!
One other question, does the sPW look too long for idle?
It sure is hot out, and I'm a few states North of you.
