jy3502 Posted July 2, 2009 Share Posted July 2, 2009 I HAVE A 91 THUNDERBIRD 5.0 HO WITH FUEL PUMP PROBLEMS. I HAVE CHANGED THE PUMP, FP RELAY AND PCM RELAY. PUMP WORKS. I JUMPED IT AND HEARD IT RUNNING. EVERYTHING CHECKS OUT EXCEPT THE FP RELAY. (I HAVE TRIED 3 NEW ONES). VMETER SHOWS POWER COMING IN TO THIS POINT, BUT NOTHING TO THE PUMP. I’M STUMPED. ENGINE CRANKS BUT WON’T START. THE VIN# IS 1FAPP60T8MH163029. ANY IDEAS? Quote Link to comment Share on other sites More sharing options...
RangerM Posted July 3, 2009 Share Posted July 3, 2009 On my 1993 Ranger I have a fuel pump "kill switch" located in the passenger floorboard. It is intended to engage in an accident, but (may be a stupid question) have you looked to see if you have one, and if it needs to be reset? Quote Link to comment Share on other sites More sharing options...
smandzak Posted July 5, 2009 Share Posted July 5, 2009 I believe the killswitch on these cars is on the driver side of the trunk behind the tire & up high, I believe the red switch is visible through a hole in the carpet. There should be 12V passing through the switch. We had a similar issue where no power was getting to the pump, but the relay box was powered. The problem turned out to be the signal wire from the PCM to the relay box. It has to be switched on by the PCM, so I would check that line. We had a bent pin that didnt make good contact. Quote Link to comment Share on other sites More sharing options...
napoleon Posted July 6, 2009 Share Posted July 6, 2009 If the inertia switch is set check to make sure you have a full 12v through it when the pump is running. What happens is the little marble in there sits in a metal cone and over time in the trunk if there is moisture the contact between the two will corrode and cause issues. Try just jumpering around the switch to test the pump. Sometimes even if you do see 12v around the switch once there is a load on it the voltage will drop and the pump will not run correctly because of the bad contact. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.