aussiebob Posted Thursday at 11:54 PM Share Posted Thursday at 11:54 PM Lost voltage to fuel pump any ideas 88 4.0 L Link to comment Share on other sites More sharing options...
fiatslug87 Posted Thursday at 11:56 PM Share Posted Thursday at 11:56 PM What year truck? Put some vehicle info in your signature. Link to comment Share on other sites More sharing options...
gogmorgo Posted Friday at 01:22 AM Share Posted Friday at 01:22 AM Lost voltage measured where? If you’re measuring just at the pump connector it wood be useful to know if it was on the power or ground side. The fuel pump only cycles for a few seconds after key on without the engine running. A better way to confirm power transmission would be jumping pins 30 and 87 at the fuel pump relay. Then you’d know if there’s a wiring concern or the truck isn’t asking the pump to turn on. You might as well check from proper power at the relay as well. Link to comment Share on other sites More sharing options...
llhat Posted Friday at 04:55 PM Share Posted Friday at 04:55 PM ^^^ xlnt advice , one could also access the starter relay and test fuel pump by unplugging connector for fuel pump and applying 12v to that wire, this bypasses the relay and the ballast resistor, pump would run continuously on my 89, the terminal was beside of the large stud at the top of the relay shown on the top left in the image below. this terminal has power applied during the start cycle and drops out after you release the key, Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now