I need someone to help me diagnose my problem. I tried to jumper wire the open circuit relay from B+ to the FP. Supposedly it’s supposed to work and get power to the fuel pump but when I did it nothing happened besides my truck not cranking over anymore. When I put the relay back on the plug the truck doesn’t crank over, it did before I started messing with the relay. Any help is appreciated, thank you

 

Is the battery sound, and fully charged??

 

Yeah, the battery is at 100%

 

Check fuses.

Is this a no crank (turn key to start and nothing happens) or a no start? If it ia a no crank, I would focus on fuses. Then possibly double check your relays (not just the one you pulled, but those all around it.

 

It’s a no start issue, it cranks over just fine. I can’t get any fuel to the engine. I checked the open circuit relay and it seems to click on and off correctly but still can’t get it to work.

 

Verify you have power at the pump. First step is to turn ignition to "ON" and listen for the pump to turn on. If you can't hear the pump run f r a few seconds, then confirm you have power to the pump (top of gas tank, you should be able to get a multimeter probe into the connector without having to drop the tank or pull the bed). Get the multimeter set up and have someone turn ignition to "ON" and you should have 12v to the pump for a few seconds.

If you have no power to pump, then you are troubleshooting wiring/relays, etc.

If you have power to the pump but no sound, you are replacing the pump.

If you have power to the pump and sound, then you need to check fuel lines (I seem to recall my old 85 did not have a fuel filter, so you are basically checking for flow and pressure at the injector rail). If you have pressure and flow to the injectors, then you don't have a fuel supply issue (and it is something other than fuel pump/supply).