Hey guys, the computer lingo "garbage in garbage out" probably applies here so I will try to cover as much background as I can without typing a novel.
I have a 180K mile L59 pulled out of a Yukon a year ago that I drove before I helped pull it, it idled fine, drove fine, made no noises. It is clean inside, bearings look great, replaced gaskets and seals. Oil pressure is 42 at idle and 50 off idle. I have it mounted in a Jeep chassis in the garage and recently installed a factory harness and fuse box to start it.
Plug wires replaced with Standard Motor Products, not what I planned but they are new.
I did swap the MODEC injector plugs with EV6 pigtails and crimped spade connectors assuming I may use the harness again on a different engine.
I flashed the ECM disabling VATS, EGR, EVAP and rear O2's.
Front O2's are hooked up to 8" exhaust stubs that end about 3" after the O2's, pointing straight down (LS3 manifolds).
Re-checked exhaust manifold bolt torque and intake manifold torque after gasket replacement.
Gas tank is from a 97 S10 Blazer with the fuel tank module that puts out 54 psi running, gas 97 octane is fresh and tank is clean.
E85 sensor is hooked up.
Have a radiator hooked up.
Checked for open vacuum ports, none found.
PCV vacuum fitting is cracked, duct taped.
Fuel regulator vacuum fitting is cracked, disconnected and vacuum port is capped.
It didn't start the first time and took three hours to find the little 12ga ground that apparently was for the injectors at the front of the engine. It started but idled rough and rich.
The first issue I started chasing is +25 on LTFT B2 with no improvement after the following, plugs are real black.
1. Swapped coil packs from B1 to B2
2. Swapped O2's from B1 to B2
3. Cleaned injectors
4. Replaced intake manifold gaskets.
5. Reversed O2 and coil packs back to the correct side.
6. Checked plug gap, .035 Delco 41-462
7. Ran compression dry compression test, 1-7 200, 202, 202, 202, 201, 202, 200
Next step was adding channels for misfire and #4 is bad and #6 worse, #2 off and on.
Last log is attached and I appreciate any input in advance.
My thoughts, it should run as it did from the factory, I didn't change anything in the tune other than what is listed above.
My next thought is to swap injector 6 with injector 2 that does not seem to have misfires.
If that does not work, replace the 14 year old coil pack wire harness, they are fairly cheap, but I have already swapped coil packs.
I also have the E85 codes, both high and low voltage and alcohol percent is ~35% when I used 87 octane.