engine cut out at idle when hot, no fuel pressure

[greenstingray]

My 85 (115,000 miles) has just started to give me a problem where she stalls out when hot over 200 degrees. She will not startup until it cools down. No check engine lite. I started by changing the ingition module, coil and cap. The fuel pump was changed about 1 1/2 years ago. After installing the parts the engine started up fine then died when it got hot. I pull the pump checked for volatage at the pump, lite when on then out, so I changed the fuel pump relay.(fuse is ok). I attached the pump to the battery and it spins, so do the blades. Just to make sure I changed the screen, reassembled everything. Car starts then it died when it got hot, again no fuel pressure. I jumped the relay its working, I jump power to the ALCL (g) test lite goes on. Anybody have any ideas (I also changed the fuel filter the same time I put the pump in last year. When its running the fuel pressure is about 35 lbs.

 

[Robertwav1]

I just worked on a car with a simliar problem. Did you change the stator in the distributor? Sounds like you did everything else. BTW, the computer probably shuts down the fuel pump once the car stalls. I found this out the hard way, this is probably why you don't show any voltage at the pump. Hope this helps!

 

[sothpaw]

My distributor was the problem when I had similar symptoms.
But then, my car is very different from the L98

 

[greenstingray]

No I did not change the stator was that the problem with the car you worked on? The questions is what is causing the pump to shut down. thanks for the reply

 

[Robertwav1]

Well, like I said before, the pump will shut down if the engine stalls. The computer senses the stall and de-energizes the fuel pump relay. The stator is hooked directly to the ignition module which is monitored also by the computer.

 

[greenstingray]

Thanks for the reply; I was thinking of vapor lock myself. I just spoke to someone who suggested that when it stalls out again to pull the plug off the oil sending unit (two tabs) and jump the plug with a wire, if I get fuel pressure, its the oil sending unit. The second thing he suggested was to pull the computer down, leave it plugged in, start the car and heat with a hair drier, if it stalls, then its the computer. I don't know I have try this stuff out.

 

[Robertwav1]

They sound like good suggestions. I would imagine they are more directed to the specific car that your working on. At least you have something to go by and try out...get these things out of the equation and go from there.

 

[greenstingray]

Thank you for your help; Well I tried the hair drier, it didn't cause the car to stall out. I was able to reproduce the problem, and I jump the plug for the oil pressure sensor. Guess what the pump started running (fuel pressure). I just changed the sending unit. 8.50 @pep-boys.