I have an '89 yj 4.2l with mpi conversion although I am not certain if it is from the mopar kit or is a mix. The pcm is for the 4.2l mpi conversion and the intake is stamped as a 4.0l intake but I dont know if its been modified and if the mopar used the 4.0l intakes or modified 4.0l intake or something else. I would really apreciate the wiring diagram for the mopar kit because I'd like to be able to sort out how this should look. I am interested to compare the mopar conversion wiring with the 4.0l wiring and my own system to get a clear picture of how this thing is put together so I know it's done properly. Just to add, I didnt do the conversion. My father paid someone to do it 20 years ago and he said there were some hinky things about the work and that it didnt seem to gain power afterwards and in fact possibly lost a little power. He told me it first didnt run right at all, stalling out , and he took it back in and the guy added a "chip" and then it still wasnt running like he hoped. Well, i dont know what adding a chip means, and why it made the jeep functional. All i know about the system is what I've said. Oh, except that its a double rail mpi and that the first external fuel pump would fail in heat + altitude and the new pump is loud as hell and it still fails in heat + altitude. My guess is vapor lock or the pump is overheating. i checked and it's compatible with in in-tank pump so I figure I'd put that in and that it would solve the pump issue. And also, I figured I'd add all new sensors and whatnot to the efi to make sure the pcm has all the data it needs but I'd still like to wrap my head around the wiring so I know it's receiving the data and able to act on it correctly.
