[drewbot]

90 lx 5.0 the fuel pump doesnt run when the key is turned on. figured it was shot. when i disconnected the inertia switch in the hatch area, figured i'd try a test light just for giggles. turned the ignition on, connected the test leads,the tester didn't light. is this normal? tested the light on other circuits and it works fine.

 

[Rookie38]

The fuel pump relay for my 86 is under the driver seat. You should have a hot wire and an ignition going to it. Pull the relay and check to see if you have 12v from the ignition. I had the ignition wire crap out on mine and had to run a new wire to it. If nothing from the key try jumping the 12v hot from the battery straight to the fuel pump connection and see if you hear your pump kick on.

 

[torino501]

the pump wont stay on unless the engine is running,it'll pressure up for just a sec or two just as you turn the key on,as the engine turns over pcm see's it trying to start/run,then it will power/press up

 

[SawBones25]

I just put up a post in the 79-95 forum on a similar problem I'm having.

I've got power to the relay, but none at the fuel pump. Tried three different relays and still nothing, so I'm ruling that out.
I talked to a few Mustang tuning gurus and the concensus is the power wire is grounding out somewhere between the relay and the pump. They said it's a pretty common problem...