I've been working forever on my neighbor's truck and seem to be getting nowhere. It has a 302 and only 1 fuel tank. I can jump power from the fuel relay and make the pumps work so I'm sure that both pumps are working. When I turn the switch on all of the wires on the fuel relay get power except the one going to the inertia switch. When I ground pin 6 on the eec self test plug it makes the eec relay sound like it is shortening. I have a couple of working relays and the all make the same sound. The only thing else I could think of was the engine control module. At one time I thought I had the fuel pumping (which I didn't) and it wouldn't crank so I was gonna crank it using starting fluid and it still wouldn't crank. So now I have two problems. Can the ECM cause both problems?

 

WHen you turn the key on you should get ground on the tan/ lt grn wire. The ecm grounds it to turn the relay on.

 

Right, I don't know why I said all the wires get power, just the red. I'm guessing yellow is constant power, red is from the switch, peach/black goes to the inertia and tan/green which is the ground. When I turn the switch on the red wire gets power and that is it.

 

I've seen this before. Are all the case grounds for the ECU intact? There's a ground wire that connects to a wiper motor mounting bolt, and a smaller black/green ground wire that connects directly to the battery. Make sure they're solid and connected. While you're at it, you should move that wiper ground directly to the battery.

 

I went back to my fuel relay and I was right on my first post. All of my wires are hot when I turn on the switch except my wire going to the inertia switch. does that mean my control module is not grounding that wire?

ri_truck_guy I see the ground on the wiper and looks like its grounded well. As for the negative battery cable I see where he has changed it out with an aftermarket cable which it doesn't have the extra ground wire on it. But I'm pretty sure it has had to be on there well over a year without any problems.