Little help please.
I need to troubleshoot an issue with the gas feed on a dual tank 85 truck. It is a carb'd 460 with the in-tank pumps. No frame pump, no mechanical pump. The front tank has a 4 wire connector on it, and I haven't dropped the rear tank yet.
I'm not getting any fuel level indication from the tanks. I added ~2 gals of fuel to the front tank (it has a seperate fuel intake issue - that's why I didn't put more in) and didn't get any change in the fuel gauge.
The rear tank feels like it is empty, so idk if it has a gauge issue or not.

The book I have (Chilton) doesn't have the correct color codes on the wires for the pump. It also doesn't trace the wires back to a fuse or relay that I can find.

Q's. Is there a fuel pump relay on this truck?
Is there a fuse for the pumps?
What are common issues with these? (selector switch in the dash, the selector on the frame, pumps?)
Can you take the connector off and check for power with just a test light? I tried, but I was just grounding the light to the frame and checking for voltage on each pin. Maybe I have to cross pins?
Which pin(s) are power to the pump so I can apply 12v and test the pump?

Oh, and this is all factory, no butchering that I can see.

Thanks,
Blair

That is factory, Ford called it the hot fuel handling system, it's to prevent vapour lock.
There is a fuel pump relay, it's around the hood hinge area on the drivers side of the firewall.
The relay receives it's switched power from 2 sources, the powered in run circuit comes from the ignition switch, runs through an inertia switch(was on the pass side of the trans tunnel on my 86) then through an oil pressure switch(top of the block behind the intake, on a Y with the guage sender, the switch is the 2 wire one) and then to the relay.
Power in crank comes from the I terminal on the solenoid, the wire runs forward from the solenoid, across the rad support, and back down the drivers side to the relay.
Power from the relay rusn to the dash switch and then back to the tanks and tank switch.
I know that from the dash back to the tank switch the sender wire is yellow with a white stripe, I can't remember if it changes colour to a specific one for each tank or not after it comes out of the tank switching valve.


As for the conector pinout, it's been a good while since I played with that stuff, as the pump on my 460 just hasn't given me grief since I've had the truck. And, I eliminated most of the factory wiring when I changed the cab and just have a toggle switch on the dash for power... LOL

This should help though:
http://i54.photobucket.com/albums/g103/82f100swb/sendingunits/lowpressandndieselrear2.jpg

Ignore the sender on the right, that's for a 6.9.
These are rear tank sending units, but, the pinout is the same, the black wire is pump ground, red is pump power, yellow is level sender, and the pin with no wire is ground for the sending unit

Sweet, thanks for the info!

I also have a question regarding 1985 Ford F-250 4x4...

Mine has 351 Windsor, 4 Barrel Holley Carb...Here's my Issue, Truck Runs Great however last weekend went off roading, hit a few big puddles...day after truck would start up but dies after about 45 seconds, at first I was thinking it was a vacuum issue...But I let it sit for about 4 days, then started right up and stayed running. Took it to the car wash, got into intersection in town and it died again. Same thing stays running for about 45 seconds then chokes out. Sounds to me like it's not getting fuel and the tanks are full. I checked the Distributor and there is no moisture, all wires are tight. I'm thinking maybe a Fuel pump issue? or possibly exposed wires somewhere that's getting wet? Do you guys have any ideas? I have no problem with dropping the tanks to replace the pumps.

Ron -