Chrysler Repair: 1996 Sebring Wont start when hot, no codes, fuel pump relay, cam sensor

Question
Hi Roland:

Hopefully you can help me out.  '96 Sebring, 4-cyl, 5 speed.  Won't start when hot.  Must open hood for 10-15 minutes and all is OK.  I replaced the water temp and air intake sensors, no help. There IS spark, no fuel.  No check engine light nor codes.  I cannot hear the pump for the 1-2 secs and was thinking fuel pump relay, but cannot locate it.  It's my daughters car, and I'd hate seeing her starded somewhere.

Thoughts

Koz

Answer
If you can hear the fuel pump when the engine is cold but not when it is hot that is significant. In the'95 Sebring sedan there is a row of four relays mounted on the firewall on the driver's side of midline. The relay that is nearest to the passenger side is the fuel pump relay. You could pull it and jump from cavity 8 to cavity 2 which will cause the fuel pump to run and see if that solves the problem which suggests that the relay is bad or that the crank or cam sensor is failing when it heats up, but without setting a code*. If one or the other of those sensors fails then the autoshutdown relay will not close and thss prevents the activation of the fuel pump because of lack of voltage to run it. So give that a try to see if you can start it when hot with a jumpered fuel pump relay.
Also you might listen for the sound of the injectors when it will and will not start as you crank it. That might also corroborate that the ASD relay is not closing.
Roland
*These Hall effect-based sensors often fail in a manner where they will work when cool, then die as heated, then recover when coled again. That usually sets and 11 or a 54 code but it is not guaranteed to do so. You could check whether the relay is getting the close signal by measuring the voltage at cavity 4 of the relay socket. It will be grounded when it is being asked to close and read 12V when not. The socket cavities are numbered from left to right with the external tabs on the top, starting a 1 on the left column of the top row, I believe. but check for numbers engraved in the cavities or printed on the relay.