Hi, Ive finally got my 1987 Silverado swap on the road and it needs to be tune and was looking for information on how to adjust fueling at idle to put some solid shake down miles on it before it gets tuned by a professional. The l83 pcm is way different than the ls1 and doesn't have the same table that I'd say I'm more use to seeing to tweak the fueling. I don't have a wide band, but I've had goodluck with the 14point7 setup on my ls1 swap. If needbe, i could invest in a 2nd setup if its going to be necessary.
L83 6l80e from 2015 Tahoe
stock engine internals, long tube headers, catless 2.5 exhaust, k&n filter, 5 bar fuel regulator w/stock fuel pump control module.
new A/C Delco mass air flow sensor and pre cat o2 sensors (from amazon)
Ive tried connecting the crank case lines together w/5/8 hardline then single 5/8 hardline to intake tube, but cant tell if it makes a difference, the long term fuel trims still go -18 or more, then hover there and since the short term can correct fueling at that point.
other things that I've notices is the idle rpm does not match commanded when the LTFT are maxing out, say 500 rpm when commanded 620 ish.
attached is a short idle log, reset fuel trim prior to recording
attached is the tune file
tune file is stock engine with a small bump in idle with changes to vats and vats related, gearing and fan controls
appreciate time taken to read and would greatly appreciate advice on how to correct this issue. Monday I have to work and will smoke test the exhaust to see if I have any leaks
thanks,
Clint