My 740GLE wagon has developed a new problem. Yesterday while driving down the road it was running perfectly and died as if I had turned off the engine. After about 5 minutes it restarted and then died a couple of minutes later. After a second try it restarted and I was able to drive the 5 miles home. Unfortunately the problem won't stay long enough to determine if the cause is spark or fuel. My best guess is the fuel pump relay is failing. I suppose it could also be the hall sensor or the power stage. Does anyone have any other thoughts as to what might be causing the problem?

 

Radio suppression relay. It actually controls the fuel injection. It was a big part of my problems when mine was doing that, it was failing intermittently. If you have an electric fan and it works, the relays are the same and you can switch them to trouble shoot.

 

Pretty hard to diagnose without testing but you could try a new fuel pump relay/radio supression relay. I would also make sure all your connections are tight and no wires are grounding out etc...start there if that doesn't work I'd test your fuel pump...is this a Regina car or Bosch?

 

The car has the bosch ignition system. Unfortunately the car doesn't have an electric fan so I can't swap the relays to help isolate the problem. However considering the price of the relay I will probably buy one and see if that fixes the problem. Thanks for the help and I will let you know what happens.

 

It's an 88...so Bosch. I agree it could be any of the above. And maybe even the crank sensor. My money would be on the pump relay as they seem to fail, here at least, more often than power stages or injector relays. Here's some info for trouble shooting...

Fuel Pump and FI Relay Diagnostic Tests. Here is a procedure to test the operation of the fuel injection relay and the operation of both fuel pumps. The 3 main things to check in the fuel circuit are the fuel pump relay, and the 2 fuel pumps.

CAVEAT: The main fuel pump is not designed to be run without the in-tank pump "on", so get the second part of this test over quickly. You should not need to keep it running in this condition for more than a few seconds to complete this part anyway.