Discussion Starter · #1 ·
I made a post on here a few months back trying to get my 89 5.0 in running condition and we got there, all it needed was a new ignition switch. I got a rebuilt ECU out of that thanks to my troubleshooting. Anyways, now that it actually will start, it seems to not like to run cold. This morning, I tried to start it and it only turned over repeatedly. I got tired of that and swapped in a HUG2 ECU from a late model 5.0 f150 that we had for troubleshooting, and it fires right up. Granted it doesn't run extremely smooth, but its a lot better than what it does when I plug the A9L back into it. I let it get warmed up to 130 with the HUG2 installed, then I swap the A9L back in. Now when I start it, it has a terrible idle, like a serious vacuum leak; however, when it warms up to about 180, something literally clicks and then it idles and runs perfectly. Heres a link to a video of it doing it. The grinding noise comes from the passenger side near the front. My speculation is that the solenoids for the smog pump air bypass and the EGR regulator turn on all of a sudden, thus hearing air escape from the bypass and opening the EGR valve, but I lack knowledge on how that whole vacuum system operates. With it running decently with an f150 ECU and terrible until something has to physically shift with the stock rebuilt ECU, I have a feeling it has to be the rebuilt ECU. It has a lifetime warranty also. I'm open to any suggestions. Thanks.