89chevy4scrap
Newbie
I have a 1989 k1500, I’m trying to figure out how to test the voltage to the fuel pump. I used a volt meter connected to the pump ground to test the harness that plugs into the pump but I’m a little confused. I tested the the purple wire in the harness and it only showed 8 volts so I figured that’s where my problem lies (intermittent running). But as I do more research it seems to me that the purple wire is only for the fuel gauge and my gray wire is my power. I am confused because when I hook my voltmeter up to the gray wire and turn the key it seems to show no power at all (even in the first two seconds of turning the key. The confusing part to me is how can my truck run at all (sometimes for 10 minutes or more), if my power wire has no voltage going to it. I’ve also either cleaned or replaced every single ground I can find on the truck including the one going from the pump to the frame rail and from the pump harness up to the thermostat housing. I’ve also tested power from the inline fuse and the relay for the fuel pump and they both show the same voltage as the battery. I’m no expert at all when it comes to electrical so any advice at all is greatly appreciated.