new member here. i know the no-start issue has been discussed a lot. and I have searched the forums and none seem to match my description. I have an 88 4+3 that I recently purchased. the car ran great when I got it, one day I was driving and it died on the highway. towed it home and had no fuel pressure. without testing for power at fuel pump, I replaced the fuel pump. after replacing fuel pump and filter, car started up after priming. 40 psi at fuel rail. I let the car idle for about 30 minutes and then took it for a test drive around the block, I made it halfway and the car died again and would not restart. had the car towed back home and when the car got to the house it started up and could not get it to fail for a couple of days. i test drove again and when i stooped at the store the car would not restart. if i jump the fuel pump relay i can hear the pump run and get the car to start. i replaced the relay and the car started, the first time. next day i went to start the car and it would not restart. if i can jump the relay and the pump runs, i am assuming my wiring to the pump is good. i have checked the wiring from the relay connector to the FR fuse and all seem to be good. i have 12v at the connector where i should and 12v from the ecu for about 2 seconds, which from what i have read is normal until the car starts. could the oil pressure switch be heating up and opening causing this stalling issue? any other thoughts i have missed would be appreciated. thanks. sorry for the long post

 

Check your relay harness and see if the insulation looks like garbage. That's pretty common. This may also be a grounding issue. You could also just have a trash harness, making an intermittent connection. In this case the car should not die once running however as the oil pressure switch would close and keep the pump running.

However if the car is running, and it dies and you are SURE its fuel, you would have to check the ground on the sending unit in the tank OR the condition of the wiring from the fuse to the pump on the 12v side. It sounds like an intermittent wiring connection.

 

any chance the oil switch is getting hot under normal temp and opening again to shut off the pump

 

No, if the car is running the ECM is commanding the fuel pump to run through the relay when it sees distributor pulse from the reluctor ring. The oil pressure switch is a redundant backup in case the relay craps out. If it did get too hot and open, you'd also need the condition of the relay not making contact in order for there to be no 12v to the pump.

The oil pressure switch being some fail safe to kill the pump in case of a loss of oil pressure is one of the biggest widespread myths of TPI cars be it a c4 or an F body.