87 tbird wont idle. Reply #15 – December 12, 2011, 04:34:02 AM Alittle more history on the car.Right after he bought it, fuel pump quit working. On a hunch, had him swap the filter and relay to fuel pump. When he swapped the filter, the old one was very old. It was actually rusted through in some parts. Still didn't work. Had him check the fusable links, and he had a connector that he thought might be bad. I told him to cut out the connector and splice it back together. After he did that we had the relay, but the car still wouldn't start. Towed it him when I could get up there later that night and called it a day.The next day we checked power coming out of the relay, and it did. Checked the coil and fuel injectors and they were both working, ruling out the tfi and pip. Pulled the filter to see if we had fuel, and the pressure was obviously low, because it just trickled out with the key cycled on and off. We could hear the pump, but obviously not enough flow. Swapped in an airtek pump and all was fine, for about a day.Next day, ran out, re-checked everything. Decided the tfi might be bad because we were getting an intermediate signal at injectors. Fuel pump was priming, but the car started fine on ether after the tfi swap. Hooked up a pressure tester, and when we cycled the key on, got a slight bump in pressure, but barely moved the guage. Hooked it to my crownvic and we hit 40psi instantly.Towed it home for the second time in two days. Double checked power at the relay output, and it was good. Pulled the airtek pump out, swapped in a rebadged walbro. Checked pressure and jumped right up to 35psi on the first key on. Car ran fine and felt like it had a bit more power. Ran okay for a couple of days.Then, the car kept randomly dying. Figured it could be the iac, or tps. Cleaned the iac, still wouldn't idle. He swapped the tps without checking it and got it to a freinds house. That is where this thread started.Now I am wondering how many of our problems were the ecm ground to begin with. I wasn't there when he spliced the connector out, so I did not think anything of it, until I realized it was the ecm ground. Quote Selected
87 tbird wont idle. Reply #18 – December 12, 2011, 09:23:41 PM The reason the EEC ground wire is near the battery is because it is supposed to go to a "pig tail" wire on the negative battery cable. Quote Selected
87 tbird wont idle. Reply #19 – December 13, 2011, 04:35:39 AM Yeah. I belive in checking ground wires, but all I knew was that we had 12v on the tps and no ground between the tps and battery. I assumed there would have been more then one ground through the entire haress, and that the computer was grounded seperately. Going back to my computer days, I had similar issues with a power supply back in the day. Ended up that I burnt up the 5v rail and it was putting out 12v and fried the motherboard.Had I knows that the tps ground wire made a giant loop through the whole harness, and realized I had 12v at the sigrtn wire, it would have all made sense. I just had no idea there was litterly one ground for the whole harness and battery. I also didn't even know if the computer regulated anything down from 12v to 5v, like a computer power supply. It gave us all the same symptoms as a blown eec, and we didn't know where the ground ran. I have honestly never had a break in that wire on any car I had, and didn't realize it was broken. Its not a mistake that will be made again.That butt splice was a temp fix. The two wires are a different guage, hence the connector that was cut out. We will hit the junkyard and cut out a new connector and put a good splice or solder that wire. If it were my car, I wouldn't feel bad adding a couple extra grounds to that wire. It seems stupid to have that small of a wire with only one connection for everything that runs the car.Lesson learned, won't happen again. Quote Selected
87 tbird wont idle. Reply #20 – December 13, 2011, 04:35:55 AM Yeah. I belive in checking ground wires, but all I knew was that we had 12v on the tps and no ground between the tps and battery. I assumed there would have been more then one ground through the entire haress, and that the computer was grounded seperately. Going back to my computer days, I had similar issues with a power supply back in the day. Ended up that I burnt up the 5v rail and it was putting out 12v and fried the motherboard.Had I knows that the tps ground wire made a giant loop through the whole harness, and realized I had 12v at the sigrtn wire, it would have all made sense. I just had no idea there was litterly one ground for the whole harness and battery. I also didn't even know if the computer regulated anything down from 12v to 5v, like a computer power supply. It gave us all the same symptoms as a blown eec, and we didn't know where the ground ran. I have honestly never had a break in that wire on any car I had, and didn't realize it was broken. Its not a mistake that will be made again.That butt splice was a temp fix. The two wires are a different guage, hence the connector that was cut out. We will hit the junkyard and cut out a new connector and put a good splice or solder that wire. If it were my car, I wouldn't feel bad adding a couple extra grounds to that wire. It seems stupid to have that small of a wire with only one connection for everything that runs the car.Lesson learned, won't happen again. Quote Selected
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