Problem: Poor bouncy idle
Engine Application: 1951 Chevy Suburban with 2005 GMC Envoy Denali, 5.3L V8, LH6, 4L60e, completely stock engine except for an AEM dry filter. Has DBW throttle and DOD.
History: In 2005 I purchased the engine/trans from a GM Special Event Vehicle sent to the wrecker with 10 miles. I installed the engine with a new harness and computers from Speartech. Everything worked great. Smooth idle, excellent throttle response. Then I started restoring the Suburban and time/life flew by. Fast forward to 2020 and I'm finally starting the engine again. I think I did everything possible to bring it out of hibernation safely.
Lightly oiled cylinders and turned over by hand.
Changed oil and filter.
Prepressurized the system with an external pump.
Cleaned the fuel tank.
Replaced the in-tank pump and filter.
Cleaned the fuel rails and installed brand new stock injectors.
Replaced a missing vacuum cap on the manifold.
Reversed the coil harnesses that I had on backwards.
Cleaned all spark plugs.
Checked continuity of the O2 sensors.
Current status: After 3-4 starts that sputter and die after about 3-10 seconds the engine will finally sputter, speed up and then settle into an idle that is rough and jumpy. If it catches, sometimes it will run for a couple minutes. I haven't run it longer because I'm waiting on a drain plug for the radiator so no cooling right now. I'm hoping the computer just needs to run longer for the computer to learn the parameters again?? When it does catch and run I've tried tapping the throttle and it'll rev and sputter and then idle down and die.
Might also need help learning to attach my log file.
11-11-2020.1.hpl