Thanks ArdWrknTrk,

I just saw your post. Thank you so much for all your help! I will give your recommendation a try the next time I'm at my friends house. Very good info my friend.

Also I wanted to post a copy of the 1987 Hot Fuel Handling wiring diagram for the 7.5L 460. Maybe this will help the next guy.

 

Maybe I'm confused...
I see the senders and the gauge but no pump wiring in that diagram.

Looks very much the same as Subford's diagram

 

ArdWrknTrk, Thanks for you last post. It was a big help. I dug in and read a bunch of other forum posts on troubleshooting the 7.5L Hot Fuel system. Understanding how it all worked helped me to find the problem.

Here are a couple of other diagrams that may help anyone with a 1987 7.5L 460 carb model.








After changing out the Ignition switch actuator and key switch tumbler the truck wouldn't start. I thought I had damaged something by leaving the battery connected with the ignition switch in the run position overnight.

It ended up that I didn't damage anything. The Fuel Tank selector switch has an intermittent short in the front tank setting.

After running thru the trouble shooting steps I had written out I couldn't find any shorts. The relays tested out and the elec fuel pumps were working.



I disconnected the fuel line at the carb and jumped the wire connected to the starter solenoid ("I" connection)to the positive battery terminal. I then left it connected for about a minute and fuel came pouring out of the open fuel line.

I connected the fuel line and the truck started right up. It ran great for a while but then ran out of fuel after I was re-installing the fuel selector switch in the dash. Again it wouldn't start just like before.

So I disconnected the fuel line again and jumped the fuel relay wire directly to the battery again. I switched the fuel selector switch to the rear tank and I had fuel pouring out of the open fuel line. I then switched back to the front tank and also had fuel.

Problem is the Fuel selector switch has a glitch in the front tank selector position. So far we have left the switch on the rear tank and the truck runs great.

I will change out the switch the next time I can get over to my buddies house.

ArdWrknTrk, Thanks again for your all your help!

Also a big thanks to Subford as I had read a bunch of his helpful posts too.