Disconnected MAP got (prob)less than 1v up to 3v.

But I think I solved it: I reached back and pulled all the wires in that taped group behind the engine a few times and suddenly I was reading 5v everywhere I was supposed to. Started the car and the trouble codes went away and she ran as good as she did before all this started happening. Still a little rough but she gets down the road. Changed back to the old computer, still ran good, still have 5v. Gonna test drive it in a bit, then try to take her to town.

Sounds like a short someplace. Is it likely to be the gray 5vref wire? If so, can I just run a next wire from the computer to the tps and map? Would it be a "partial" short in that line giving me the 3v? Thank you for all your help...I remembered reading someplace here to try pulling those wires. Hope that fixed it for now.

 

The test in post #30 probably would have indicated a problem, which would have led to more tests to find the short circuit. More than likely either the reference voltage or signal return wire, (or both) are intermittently shorting to ground. Look the harness over for being pinched or insulation worn off of the wire(s). You're on the right track now.

 

Yes Captain Hook, the test in #30 showed low voltage, 3v. I didn't cut the wire to the computer to see if it was putting out 5v...I should have done that. I tested the gray wire from computer connector to the TPS connector, and it was good....at the time, though I wasn't getting any voltage to the TPS. If the signal wire can short the 5v, it might be that one that is doing it. At this point I'm thinking about taking a break from worrying about the car.....as long as it is not shorting now. It's been about 4 weeks that it has been down. Lol, got a lot of excersize though (4 mi. to and from the grocery store).

I will test the signal wire if it starts shorting again, but gonna pray for a few weeks to get back to work.

I understand that there is a computer software that will diagnose vehicles. Could someone point me in the right direction for that? I enjoy troubleshooting computers as a hobby and enjoyed reading day in and out about this car (minus the stress). Maybe I can help someone else on island who is having problems with theirs. I appreciate all the help I've gotten in this Forum.

 

Decent scan tools start around $2K. They will allow you to access most, not all, of the PCM functions.