I have a 94 Ranger XLT 4.0 V6 I've been having an intermittent problem with the fuel pump not kicking on when the key is turned, I've replaced the pump, intertia switch and relay, and am still getting the problem at the most inconvenient times. I've read a few places that the ground to the wiring harness could be bad but am unsure where to check for grounding points the battery connection is fine.Any help would be appreciated

 

Sounds like the problems my mom's van had. A bad fuel pump can be intermittent, but it is a good idea to check the harnesses anyway.

 

Have you taken a look at the ignition switch, the real one on top of the steering column? Some will start to come apart when they get old, and need to be pressed together and re-crimped.
I think that the ECM provides the ground for the relay, causing it to close and provide power to the pump. When you replaced the pump, did you make sure that the ground straps were all in place under the bed? Does yours have an in-tank lift pump and a separate pressure pump on the frame rail, drivers side, just about under the seat? Some have two pumps...
tom

 

how about the ecu relay...........did you check for spark when you have the fuel pump not kiciking on?

 

You've been buy on this one.

I like all of the ideas posted.

The fuel pump ground point is under hood, drivers side, on the inner fender mid way up, about where the end of the power distribution box is. It's a small green painted fastner.

If you have power door locks, you'll also find the passenger side door lock ground there, along with the fuel pump ground lug.

If you have a good quality, long set of jumper cables, you could fashion a low resistance parallel ground connection, from the pumps ground connection, all the way back to the battery B- post, to check the soundness of the pumps ground lead & it's ground point connection.

Maybe consider doing an under load B+ voltage drop test to the fuel pump, to make sure the B+ feed connection to the pump is sound.
If in doubt, rig a fused B+ jumper, from the battery directly to the fuel pump & see if it runs steady.

Don't take the new fuel pump, or other parts off your suspect list just because they're new, make them prove themselves, maybe Murphys Law is messing with you!!!!

Make sure the fuel pump power relay's socket connection, the inertia switch & fuel pump electrical connectors pins & sockets are without damage or corroion.

If eveything checks out, maybe you have a computer driver connection, heat, or driver inernal part problem.
Some autoparts stores can bench test the computer.

More thoughts for pondering, let us know what you find.

 

Another thing to check is the plug for the sending unit itself. mine was making poor contact after pump replacement, got hot and would cause intermitent starting issues. found it when i went to replace the (so i thought) faulty new pump.