I just replaced the tank, fuel pump, fuel sender and sock in my front 19 gallon tank.

Before I put everything all back together, I poured about 4 gallons in to make sure it registered and picked up fuel. It did. I heard the pump running in the tank, it registered on the gauge, and the truck ran fine on just the front tank, and after finally buttoning up some loose ends with the replacement, I threw a full tank of non-oxy at her. Now, when I hit the selector to the front tank, the gauge goes down, and the truck eventually sucks all the gas out of the bowls of the carb.

I would also like to mention that upon taking everything apart, one of the ears of the fuel sender harness connector broke off. When I put everything back together, it sat on the tank just fine and didn't give me any issues. It worked just fine. I've since had to drop the tank once more to get the overflow valve put in with the correct gasket, but otherwise, the connector would not have been bumped in anyway. I fiddled with it tonight, and everything was tight on top of the sender. Everything should still work as it did before I put everything back up.

But alas, it slowly ran itself out of fuel from sucking the carb dry.

Where can I go from here? New connector? Drop the whole tank and pray for a miracle? Any foolproof ways to check if the sender is still working, or getting the proper voltage?

Here are some pictures of what the inside of the old tank and sender looked like:

 

Gauge power comes from the instrument cluster voltage regulator and pump power comes from the fuel pump relay.

If you have no gauge and no pump you either have no ground or a bad connection.

(I would check the ground)

 

Any idea where the ground is for the front tank sender?

 

You can pull the connector off the tank, and with the key on engine off, put a wire on a good ground somewhere, and touch the other end to the darkblue/yellow wire. Each time you touch it and then take it off, the fuel gauge in the dash should swing back and forth if its working.

 

I imagine G701....

I can't see sigs on mobile, so i dont know your truck.
but you can look at the EVTM on Gary's Garagemahal site.

 

It's an 86 F250, 460, Holley 4180, dual tanks with electric pumps.

 

The gauge works with the rear tank just fine though. So can we rule out that the gauge works and look for another gremlin, or is there something wrong with the connector at the tank that would cause it to not get power?

 

You may have a problem with your fuel switching valve. Turn the key on, engine off, and switch the fuel tank switch front to rear. You should hear a "clunk" each time you switch it. That would explain why the carb is going dry, if the valve is on the rear tank. And it would also explain the gauge not working, the valve switches the sending units also electrically.

 

I do recall hearing it clunk tonight, so everything should be working.

 

EVTM is here:

EVTM - ???Gary's Garagemahal


Judging by the amount of crud in the tank, I'd strongly suggest replacing it. That junk will be working loose for years. Expect the pickup sock to get covered with flakes. Any fines that get past will trash the pump and plug the filter.

 

I did replace it, that's why i'm having all these new problems.

 

Oops, I should change my signature to just say, "Nevermind..."

 

I still think if both sender and pump are not working, then it must be the ground.
And since *this* diagram (there are variants of hot fuel handling) shows a common ground with the rear tank (that does work) I'm going to say it must be at the plug or in the wire before splice 154, where ground for the rear tank *does* work.


Can you back probe the connector or pierce the insulation of the black wire to create a ground and see if the gauge heats up and starts reading?

 

Ok, so here's an update:

Crawled under the truck today, and had my dad help me out. I used a wire, grounded to the frame, and stuck the other end into the 2nd hole from the left, the Blue/Yellow wire plug end. Nothing changed on the dash.

There was also some weird stuff going on too, like when my dad switched the switch to the rear tank (which has 3/4 of a tank in it), it stayed on E. I told him to start the truck and see if it changed anything...nothing changed. Shut the truck off, switched it back to the front tank, key on, engine off, and it read 3/4 full. Switched it to the rear, still read 3/4 full. So not sure what's going on there.

Otherwise, I did not hear a clunk when he tried switching between the tanks Franklin2. So would that imply that my tank selector valve is kaput?

Also, remember that one end of my connector has broken off, so it can be somewhat loose on the sender, would we recommend replacing the plug? Would it need to be spliced, or is it a simple plug and play?

 

I suspect the valve. They are famous for giving trouble. Now comes the fun part, getting a new valve. You can go to Ford or a place that has the OEM valve, and expect to pay $200+ for it. It goes right in, no modifications. Or you can go the parts store and get the exact same functional valve made by the same manufacturer(Pollack), but it won't fit up exactly. The fuel line fittings are different, the wiring plug is different. If you don't mind doing a little rigging with the fuel lines, and splicing in the wiring, it can be made to work. It's the exact same valve, except Ford had the connections custom made for them by Pollack.