dakota1205

Have a 1998 F150 4x4 offroad with the 4.6L engine. It quit on me the other day while driving. All of a sudden it sounded like it was starving for fuel. It would just crank and crank. there is no smell of fuel around the engine. Believe it might be the fuel pump. It does not make that ~2 second whirring noise at the fuel tank. Fuel pump relay appears to be working and the fuel inertia switch (by passenger door) is also. I found the plug where the fuel pump plugs into near the fuel tank. I have no voltage while the key is off, turn key to run postition, voltage goes to ~ 11v for about 1/2 second, then voltage back down to ~5.5v, while cranking voltage increases to ~8-9v. Does this sound correct?

I have the haynes manual, it says something about checking voltage at the PCM relay. I can't seem to found that relay. The fuel pump relay also says it should have primary and seconday voltages, one being the PCM voltage and Battery voltage. what should the PCM voltage be?

Any help would be greatly appreciated.

Good old Bill

Looks like you've tested it well enough to drop the tank or pull the bed to go after the pump. The timing out of the power to the pump is about right, 2-3 seconds is the normal, I'm not sure about the 5.5 volts while cranking.