Mechanics

WHY WON'T THE FUEL PUMP COME ON WHEN I SWITCH THE KEY TO THE ON POSITION

1985 Ford Thunderbird • 140,000 miles

Ichanged the rear main seal on this car and tried to crank it no fuel to the rail. Reset the switch in the trunk. Checked the relay power to both got power. Where fuel pump is good the car was running before I put in new seal. There are some fuses in the trunk I cant identify not in the owners manual what am I missing
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James629
September 18, 2011.



Some models may have two pumps? In the diagram, pink wire is voltage. Orange wire and black wire are grounds. If you have good voltage and ground at the pump connector and no pump action, suspect the pump.


JDL
Sep 18, 2011.
MY MOM AND DAD BOUGHT AN '86, 3.8L, TBI, NEW. IT'S STILL GETTIN' IT. WE KEEP IT UP, MY MOM WILL NOT EVEN CONSIDER ANOTHER CAR.

EVEN THOUGH YOU HAVE POWER TO THE RELAYS, STILL DOES OT MEAN THE RELAYS ARE OPERATIONAL. MIGHT TRY SOME SWAPPING, OR EVEN A NEW ONE.

MY DAD HAD A INTERMITTENT PROBLEM WITH THE FUEL PUMP, HE NEVER MENTIONED THE PROBLEM, AS "HE HAD IT UNDER CONTROL". UNTIL HIS 2 YEAR LONG METHOD STOPPED WORKING.

HE WAS GOOD ABOUT NORMAL "OLD TIME" MAINTENANCE, HE FOUND THAT WHEN THE FUEL PUMP WOULD NOT MAKE A RACKET, WHEN ATTEMPTING TO START IT UP, HE COULD SLAP THE TRUNK, AND WAH-LAH! IT WOULD START WORKING!

SEEMED HIS "SIGNATURE" GOODBYE, WAS SLAPPING THE TRUNK WHENEVER HE WAS LEAVING SOMEWHERE. AT THE TIME, WE HAD NO CLUE, WHY HE DID IT!

HE WAS UNDER THE IMPRESSION, HE WAS JARRING THE FUEL PUMP, INTO WORKING, BUT WHEN WE STARTED INVESTIGATING, HIS FUEL PUMP RELAY WAS IN THE TRUNK, CLOSE TO THE LOCATION HE WAS SLAPPING. THAT WAS THE PROBLEM, THE RELAY'S CONTACTS WERE SORTA SPLATTERED LOOKING, I COULD STILL "THUMP IT" BACK INTO WORKING. REPLACING IT, WAS THE ANSWER TO HIS WHOLE PROBLEM.

I WAS HARD TO BREAK PAP, OF THE "TRUNK SLAPPING HABIT"!

THE MEDIC


Tiny
CJ MEDEVAC
Sep 18, 2011.