I have a Ford





I have 1995 Ford F-150 that will not run! I have checked the inertia switch with my test light on the feed wire and the out going wire. When I turn the switch on both wire show hot for about 3 seconds then nothing! I have changed the relay no effect if the switch is activated I can hear and feel the relay click twice any suggestion would be appreciated!!! Thanks Bill

 

Hi Bill,
The info you have provided so far is good.
The vehicle computer will provide the ground for the fuel pump relay for approx 2 seconds when you first turn the key on.
If the computer does not receive an RPM signal it opens the fuel pump relay. Safety feature.
When cranking the engine over to start , it does get that RPM signal and the relay should be closed providing fuel to the engine.

What I would suggest is ,,,when you attempt to start the engine and it doesn't start, remove one or two spark plugs and see if they are wet or dry.
If wet, we have an ignition problem. If dry,we have a fuel supply problem. Get back to us and let us know which condition you have and we can go from there..
Can you do this?

 

Thank you I will continue further will check voltage to the pump and check the ground will let you know how I make out!!!!

 

If the plugs are wet you are dong a lot of extra work because that will tell you the fuel pump is providing fuel.

 

I have checked the ignition and all looks good plugs are not wet!

 

If you cranked the engine over attempting to start the engine and it did not start,you removed a plug or two and they were dry = no fuel getting to the engine.

Could be no fuel supplied from fuel pump or injectors not working. Start with checking the fuse that supplies power to the injectors.
Easy way to do this is with a test light or voltmeter.
With the key on, power (12 volts) should be available at each injector, If not check fuse.

If fuse is open, something caused that to happen, maybe technician induced problem or possibly shorted injector.

If shorted injector, just meaure resistance of each injector coil and the shorted one will read much lower resistance.

All this can be done without doing anything except unplugging each injector to do the checking..