Mechanics

ELECTRICAL PROBLEMS

Ford F-350

1989 ford f350 with 460 engine. Something has shut the power off to fuel pumps and injectors. I put a jumper wire from battery to relay plug and fuel pumps are sending gas to rail but won't crank. I can spray starter fluid in air intake and it will run. My book says computer turns power on and off based on rpm and vaccum but does not say where these sensors are. Mileage is around 120,000. I bought it not running and have tried everything I know. Any help would be appreciated. Thanks
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Fordman
December 4, 2006.



First thing of course is to check all the fuses and fusible links in the underhood power center. If all are ok, then test for power to the EEC relay. It is the main power supply for the ECM. Check those and get back to me

Tiny
Jack42
Dec 4, 2006.
I checked all fuse links. I did a voltage test on the battery-12.77, eec relay coil side-12.45, side to be switched-3.46, fuel pump relay coil side-3.02, side to be switched 3.43. There is not enough voltage at the fuel pump relay to activate coil. If I put jumper in relay plug to fuel pumps the 3.43 voltage is not enough to run fuel pumps. I can run jumper from battery to same plug and fuel pumps will run but won't crank because no power to injectors.

Tiny
Fordman
Dec 7, 2006.
Just a thought but isn't there a safety cutoff switch? This gets tripped sometimes when jarred or tipped a bit. Have you looked to see if it needs to be reset?

Bruce Hunt
Dec 7, 2006.
Yes the inertia switch is working.

Tiny
Fordman
Dec 12, 2006.