Hello - I’ll try to make this post not too long-winded. For many years I’ve been trying to get my 1989 Chevrolet c3500 7.4l to pass emissions. Sometimes it passes, most of the time it does not. Much diagnosis and many parts thrown at her. Discovered through this forum it’s had the wrong PROM chip (ANTY). Bought a few blank chips and a programmer, and burned a new chip(AKUN). When I installed the new chip, the truck started and sounded like it was running on less than eight cylinders, then it died and will not start again. Diagnosis tells me no fuel. Through testing, my fuel pump does not run when I turn on the key, but I can apply 12v through the wire harness and it comes on. Injectors fire when voltage is applied through the harness, just not getting the fuel. I understand this is a by-pass system and by-passes the ECM until the parameters are met. Does that mean it doesn’t use the ECM at all until those parameters are met? Or does it use a base tune to start? I broke the original ANTY chip when trying to release it from the holder, so I cannot put the old chip in to see if that was the issue. There is also the possibility that I bought and burned the wrong chip. I used a M2732A 21v and the AKUN tune from this forum. Before the chip swap the truck had no issues starting or running. At this point any advice is good advice. Thanks.Questions:
1.) Did I use the correct chip for the tune?
2.) Is the ECM/PROM completely “by-passed” during starting.