I got a 95 yj with the 4.0 and manual trans. The portion of my ecm that controls my fuel pump went out. I got a used one for the same setup except it's for an auto trans. Can that get flashed to run a manual trans or no? And what does it do to your jeep if ran without reflashing it?
New ecm or pcm
- Thread starter hurthummer01
- Start date
All I recall the PCM doing for the fuel pump is the PCM grounds the ASD (auto shut down) relay and I believe the fuel pump relay power runs through the ASD. The power for the injectors and the ignition coil also go through the ASD so if your PCM is no longer operating the ASD, you’d lose those as well. So you need to confirm that the ASD is your problem, since the PCM doesn’t control the fuel pump in any other ways….
As for the PCM, they can not be flashed. They’re ancient and programmed as they are. The good news is, it doesn’t matter. The only thing you need is a 91-95 4.0 computer. The auto version will not operate your shift light. The manual will. The only picky one is a 94-95 automatic. The 94-95 autos have a lockup torque converter and need a 94-95 automatic computer (2.5 or 4.0 specific) to operate the lockup converter. A manual trans can run any same-engine auto or manual computer, so you’ll be fine. But I still have my doubts about the PCM fixing the problem. I’ll have to look into the factory service manual again to refresh my memory on the connections between the PCM and the fuel pump to verify their relation.
As for the PCM, they can not be flashed. They’re ancient and programmed as they are. The good news is, it doesn’t matter. The only thing you need is a 91-95 4.0 computer. The auto version will not operate your shift light. The manual will. The only picky one is a 94-95 automatic. The 94-95 autos have a lockup torque converter and need a 94-95 automatic computer (2.5 or 4.0 specific) to operate the lockup converter. A manual trans can run any same-engine auto or manual computer, so you’ll be fine. But I still have my doubts about the PCM fixing the problem. I’ll have to look into the factory service manual again to refresh my memory on the connections between the PCM and the fuel pump to verify their relation.