ECM question (Page 1/2) Horseman1971 AUG 17, 04:56 PM Hey guys, sorry if this is covered in another thread. I'm sitting in the car and for some reason the search function won't work with my phone. I bought a 86 gt a few weeks back that I intended to do an engine swap on. But after getting the car home I got it to fire off briefly so I'm thinking maybe use it as a daily for a bit to cut down on diesel. The PO said his mechanic told him the fuel pump wouldn't maintain pressure. I replaced the pressure regulator and am now in the process of trying to trace why it won't stay running more than a couple of seconds. I noticed the ECM that is in the car now has "86 Fiero SE V6 Auto" written on it. My car has the 4sp manual. Is that ECM looking for some kind if signal from an auto tranny that would keep it from running? Patrick AUG 17, 05:22 PM You need to check the fuel pressure... not only while the engine is running (if it'll run), but also how long it maintains fuel pressure after the key is turned off. Horseman1971 AUG 17, 05:24 PM Done that. Im getting about 48psi. It dropped down to about 25 after a couple of minutes of sitting. Patrick AUG 17, 05:30 PM The fuel pressure is good... except for the fact that it's dropping rather fast. You need to find out where it's leaking from. Within the tank? From an injector? etc Horseman1971 AUG 17, 05:38 PM Thanks. I think Im in for an electrical headache digging into all of the years of splicing im finding. So the ECM thats in it wouldn't cause any issues providing its working properly in the first place? Patrick AUG 17, 05:44 PM quote Originally posted by Horseman1971: So the ECM thats in it wouldn't cause any issues providing its working properly in the first place? Whatever is written on the ECU may not actually jive with the PROM that's currently installed. Let us know the numbers printed on the PROM. However, as long as the ECU itself is 100% functional, I don't believe even the wrong PROM (auto instead of manual) would affect the engine's ability to start. Horseman1971 AUG 17, 05:46 PM Awesome, will do. Taking a break in the AC for a minute. Thanks for the help Horseman1971 AUG 17, 06:09 PM Looks like the label says FBA 1819. Theres 2 chips. The larger one on the right is where that info comes from. Whats the smaller one on the left for? I ask because I have what I assume is the original ECM sitting in the seat also and it does not have the smaller chip Patrick AUG 17, 07:40 PM I believe the other chip you mentioned is a Calpak. It's for "limp mode" as far as I know. Some ECUs have them, some don't. I ran a search for that PROM number, and I actually came up with an old thread of mine from 2009. Anyway, the PROM you have is for an automatic. I don't know how much difference running that PROM with a manual would do. The Shift light will never come on, but that's more of a blessing than a problem! Maybe someone with more knowledge than me when it comes to ECUs could step in here. Horseman1971 AUG 17, 08:46 PM Great, thanks for the help Patrick. I appreciate it!