While driving, the truck quit, was able to restart but it quit again so rolled into a fuel station and put in 10 gal. No start at all so towed it home. Read several threads here and verified lift pump works when 12 v. is applied. Have voltage at injector relay of 12.3 volts but nothing at pin seven at pump connector. Was getting varying voltage so removed battery connections and cleaned- tightened. Swapped relays and still no voltage to pin. Looks as if fuel shutoff circuit is keeping relay open. Where do I go next? Am new to this site and have not worked on the fuel side of the motor until now. Was able to get this far because of the excellent responses to questions.

 

The fuel pressure needs to be known.
If you have an old R12 Freon install kit w/gauge, you can use it to check the lift pump fuel pressure, otherwise kits are avalable at most chain type auto parts stores.

Don't forget to close the fill valve.





Screw the connector on the fitting of the injector pump on the driver's side of the engine.
Turn the keyswitch just enough to "bump" the starter to get The Free 25 Second Lift Pump Run.



Stock spec is 10psi+, most folks look for 15psi.

 

Did you check to see if there was power to pin 5? The ECM can shut down the VP by supplying power through pin 5.

 

Any codes?