I have been experiencing a problem. After truck sits. The fuel pump will not kick on. If I disconnect the crank sensor and then reconnect, the fuel pump will then kick on. This has happened twice in last 2 weeks. Prior to this happening the pump did not come on on 2 occasion I wiggled the wire on crank sensor and pump kicked on. I replaced the crank sensor and now this problem. Any ideas why the crank sensor will lock out fuel pump then reset by unplugging.

Would like to add. Yesterday It did it again after sitting for about 2 days. I unplugged crank sensor and it did not reset this time. I unplugged fuel pump after unplugging sensor and it reset.

 

Do you have the ignition on or off when unplugging things? If it's off, and that actually works, you have bad connections.... if it's on, I suspect a bad/failing crank sensor. (just because its new..... doesn't always mean it is good....)

The pump should ALWAYS prime for three seconds when you first turn the key on. If that isn't happening, try swapping the ASD relay with the horn relay. (provided your horn works....) See if that changes anything.

 

Tried the relay swap. I am leaning toward bad connection. It is an after market fuel pump with short wire that original wire plugs into. It acted up again this morn. Unplug fuel pump and plug in and pump primed. Next time I am going to wiggle first. Not unplug. Slow diagnose process right now.

 

I think I found the problem. Bad ground wire to pump. Must have been acting up along with crank sensor. I started just dealing with one area when it would not start. That eventually lead me the the pump area. While investigating negative wires I found areas that looked like it had resistance. I uncover and rerun wire. I also spliced in and added a ground to the frame from those wire. About a dozen starts now with no problems.