06-23-2013, 05:40 PM
I just put a rebuilt 5.7 from a 96 mercruiser to replace the cracked block that was in the boat when I bought it. The only difference between the original and new block are Vortec heads and intake manifold. all EFI components are original and most are new. still using the original fuel pump relay and MAP sensor. The timing is set at 8Degrees BTDC. I've been told that I may need to have the MEFI reprogrammed to fine tune it. I have tried to start it and the engine acts as if its 180 degrees out. just a few backfires and not even trying to run. I've went through it probably 10 times checking firing order, timing and spark. All are correct. Fuel pump pressures up and I have juice going to the fuel injectors. I bought the motor rebuilt, I check cylinder compression and all were good. the only thing I didnt check for cam alignment or rockers for lash. My thought is either the cam is set wrong or the computer is flashed wrong. any other thoughts out there.