2002 Fuel Delivery Issue? Anyone have a wiring diagram?

[Dudeth]

I drove my 2002 with 4.6L to a store, when I came out it would crank but not start. I couldn't hear the fuel pump engaging and it was acting like it wasn't getting fuel or spark. Had it towed home, shot some starting fluid in the air inlet and it fired up ran for a few seconds and died. Tried this a few more times and tried to start it in between starting fluid shots and confirmed that it seems to be a fuel delivery issue. Tested the fuel pump fuse and relay and those were good. Checked the inertia switch and it wasn't tripped and was getting power but only 6 volts. My battery was at 9 volts from all of the attempted starting so it's on the charger. I'll recheck voltage to inertia switch after it's charged.

I had the fuel pump replaced last year by a mobile mechanic. The pump I bought from Amazon may have been a POS so the pump may have went out again. Am I able to test power to the fuel pump without dropping the gas tank? Any other ideas? Thanks!

 

[Bedrck47]

The reason that you may not see any voltage at the inertia switch is due to the engine not running. If the engine doesn't start the power to the fuel pump will be shut off. To check power at the inertia switch you would have to have you meter connected and watch the meter while someone tries to start the expy. You have to be quick.

Print attached for the fuel pump circuit

 

[Dudeth]

I edited my original post because I don't think my meter was getting far enough into the plug to get a reading so I stuck some wires in there and was getting a constant 6 volts on one side with the key in the run position without trying to start it. My battery was low and only at 9 volts due to all the cranking it so I put it on the charger. I'm not sure how to test power to / at the fuel pump.

 

[Dudeth]

Does anyone know where the shrader valve is on this? I didn't see it on the fuel rail. Any recommendations on how to proceed?

 

[Dudeth]

Print attached for the fuel pump circuit

Thank you !

 

[Bedrck47]

When you get the battery fully charged recheck the voltage at the inertia switch.
Just remember that you may not see full voltage if the engine isn't running

The shrader valve should be on the passenger side fuel rail

 

[Dudeth]

Got the battery charged, put a meter on the inertia switch plug and turned the key on and had 12 volts for a couple seconds so looks like everything is good there and from what I can tell the inertia switch is the last component on the hot side before the fuel pump so looks like it's the pump.

 

[Dudeth]

Fuel pump fixed it, I'm back in action. Went with a Bosch OEM pump this time.

 

[Bedrck47]

Thanks for the update