I have a 95 E150 5.8 gas engine. The fuel pump is not working (doesn't even do the 2 second pressurize when ignition is turned on). Replaced fuse (even tho it looked good), replaced fuel pump relay, still no luck. I disconnected the inertia shut-off switch and tested the supple wire - only shows 6.6v which is kind of confusing. Any ideas before I drop the tank?

 

I wouldn't drop the tank just yet.
You must have 12 volts coming to the inertia switch. If you don't have that at that point you must go back to the fuel pump relay and see if you have 12 volts coming out of there. If not go back further , it could bee the EEC relay which powers the ECM and the fuel pump relay. Keep checking back until you find where you lose the 12 volts. It could even be right at the battery or ign switch. It would be a shame to drop the tank for nothing unless you like doing extra work.

 

Thanks - I'll keep checking

 

Is the EEC relay in the Power Distribution Box? The manual just shows a PCM relay in there. Also, do you know of the existence of a diagram online showing which pins on the relay are for what? I'm not sure which pin to test for 12v. Is the ECM the same as a PCM. When it comes to automotive electronics, I'm still living in the 60's!

 

In looking around under the hood, I found a module labeled EEC TEST. It has a five-wire red connector and a single-wire grey connector. I guess the repair shop has to hook something up to this.

 

The plug you are looking at is to connect a scan tool or run some tests with an analog meter.
One of those contacts in that plug will energize the fuel pump relay when it is connected to ground with the key on.
When you are looking at that plug set it so the two end slots are like upsidedown t s.
The right handed slot when grounded with the key on should energize the fuel pump relay. If it does that then everything from the relay to the tank pump is OK and now you need to work back to find why the fuel pump relay is not being energized.
When you turn the key on power from the ign switch energizes the EEC relay and the ECM,PCM are the same thing. The fuel pump relay and the EEC relay are the same part # and are interchangable. There either has to be a poor connection from the fuel pump relay to the inertia switch or a short circuit in that wiring that is pulling the voltage at the disconnected inertia switch down from 12 volts to the 6 volts you are reading. Are you using the right voltage scale with the meter you are using?

By the way what kind of manual are you using? If the manual is for OBDII your truck has OBDI system.

 

I'm just looking at the owner's manual. It labels each fuse and relay in the power distribution box. I'm not sure where the EEC relay is. I should probably have it towed to the local repair shop so they can scan it for the error code.

 

If your manual says your vehicle has a PCM relay, see if it is where the manual says it is. Check another relay and see if it has the same #. If it does , switch relays and see if there is any change.

 

Tried it. Ended up taking it to a local tech who verified the pump was dead. Thanks for your help.

 

If it's not too much trouble could you let us know what he found. We knew the pump was dead because there was insufficient voltage getting to it since you disconnected the inertia switch and received a low voltage from the supply side. When you disconnected the inertia switch you took the fuel pump out of the system. Just curious.