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Discussion Starter · #1 ·
I have 2004, 2.7L which was running fine before and all sudden it just doesn't start. I am thinking it is the fuel pump in the tank since I don't her any noise coming from it. I checked the fuel pump supply terminal at the fuse box under the hood and I have +10 to 11V coming out when in on and cranking. I checked the voltage at the fuel pump relay and there is +11V going to the relay coil and the switch arm. I checked the voltage at the connector at the fuel pump under the rear seat and I am getting really no voltage to the pump on any of the 5 pins. I'm not sure what pins should have voltage, since trying to find a wire diagram online seems to be elusive. Is there a fuse that I am missing since at the 2 fuse boxes (under the hood and under the left panel driver's side), there doesn't seem to be one other the ECU fuses. I also pushed the rest button for the emergency shut off, which didn't make a difference. Just a note that I changed the front left driveshaft because the boots were damaged, which I believe has nothing to do with my problem.

Thanks
 

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I checked the voltage at the connector at the fuel pump under the rear seat and I am getting really no voltage to the pump on any of the 5 pins.
That's kinda telling you that the problem isn't the fuel pump in the tank. It's the pump power supply that's the problem.

You have good voltage on the pump check connection in the fusebox so it seems the pump relay is being switched on DURING CRANK.
Have you checked that there is voltage on both terminals of the emergency shut off switch when the engine is cranking? (switch connected)
 

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Checking the fuses that give power to the fuel pump
Tells you that the fuel pump should have power going to at least one line (wire)
Not finding any power suggests there is an open line
If it was shorted then fuses probably would have blown

To show it is the problem, put power to the pump and try to start engine
If it starts then issue found.
Next is to determine proper fix

Good luck
 

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Old 2.7L,,,,,,,,,,, I would verify the crank position sensor pigtail is not all crack-fray with inside wires exposed / corroded

If it get a good rnough contact to short, it'll take out 1 of the ECU fuses and aid in keeping engine from lighting fire

 

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Discussion Starter · #5 ·
I took the tip to check the voltage at the emergency shut off switch connector and found +11V on terminal and +0.5V on the other terminal. I decided to jumper the 2 terminals and I did get voltage at the fuel pump connector (+11V). I put the connector back on the pump to see if anything would happen and no change. I put the connector back on the emergency switch and amazingly I got voltage at the pump connector. I decided to then try a used pump from a junk yard before spending big bucks to see if it was going to work. The used pump worked fine. I think I am going to replace the emergency shut off switch and the pump since this seems to be where my problem is originating from. Thanks for the tips.
 

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Great to hear you managed to figure it out.

Be careful if your intending on dismantling the tank unit to replace the pump. There are a few posts on the forums here from folk who have done that and made matters worse. It might be best to replace the complete tank unit if there isn't a huge price difference between that and a bare pump.
 

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Just thinking about it a little before replacing the emergency cut off switch ...

There is power going in but not out .. supposing the switch works correctly
What would make the emergency cut off switch activate?

Well, never mind.
Guessing R & R it should fix the issue???
 

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Discussion Starter · #8 ·
In regards to the pump I decided to get a new pump assembly from RockAuto anyway, since the other one I pulled from the junk yard was from vehicle that had been sitting there for awhile. The one from the junk yard might work now but it might only work for 2 days or 2 years who knows. Now I just need to find screws to replace the corroded screws to mount the pump back in.
 
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