Faulty rigged

Just picked up this 77 c25. It smells of heavy gas fumes. I got under started looking around. Apparently they removed all the cross over hard lines to dual tanks and ran all rubber hoses. The original switch valve has been removed and replaced with two small pumps for sending and return. They also cut the plug for original switch and must of removed wire because I don’t even see 5wires to reinstall plug if i wanted to. Some of the hoses leak a bit out of ends where meet hard lines running to front. Please I need advice on how should I move forward. Should I remove tanks and only put one back or what would you do to get it properly set up?
Thanks for all advice

Welcome!
Stop, breathe, think.
The mess you have needs to be fixed, safety issue. The question is what are your plans for the truck? If a working driver, make it safe and go to work. If you are planning a restoration, then restore to original.
Eric

Dad's ole C20 Crew has a selector valve with one wire like the one in the pic. It appears that your truck has two installed for some odd reason.

Strick said:

Dad's ole C20 Crew has a selector valve with one wire like the one in the pic. It appears that your truck has two installed for some odd reason.

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Yeah, it looks like the truck had a 6-port valve and they couldn't find one, so they used a pair of 3-port valves. I don't see why that wouldn't work.

However, I do see a glass fuel filter that absolutely has to go. If it's not leaking currently, it will be.

waterpirate said:

Welcome!
Stop, breathe, think.
The mess you have needs to be fixed, safety issue. The question is what are your plans for the truck? If a working driver, make it safe and go to work. If you are planning a restoration, then restore to original.
Eric

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I’m going to use it as a work and daily short distance driver.

bucket said:

Yeah, it looks like the truck had a 6-port valve and they couldn't find one, so they used a pair of 3-port valves. I don't see why that wouldn't work.

However, I do see a glass fuel filter that absolutely has to go. If it's not leaking currently, it will be.

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Yes they put two fuel pumps instead of original valve. Some of the rubber hoses were leaking where they clamped onto hard lines. So I removed it all, time to get it all safely buttoned up

Update: I have removed it all. This is what they had going on connecting across both tanks. Also removed both fuel tanks because I have it parked in garage with water heater and was concerned about all the fumes the space was filling up with. So I figured I remove it all and inspect everything till I can get it all properly put back together. Also removed the Carburetor (one of those Chinese quadrajets) it wreaked of fuel sitting in it. The carb has no numbers or identification, I might switch to something else. Any suggestions?

Assuming you still want dual tanks - The six port solenoids with only a single power terminal have been unavailable for several years. If you can’t find a NOS solenoid, then the best choice is to switch to the newer version with a six wire connector. There are articles on the net that explain how to convert.

I have my dual tanks working, but ended up buying a lot of ethanol resistant fuel line, and then have to keep all those hose connections tight. An alternative is to swap in a Blazer or Suburban tank in the back, and move your spare up into the bed. IIRC, they had three tank sizes, and the biggest was 40 gallons.

75gmck25 said:

Assuming you still want dual tanks - The six port solenoids with only a single power terminal have been unavailable for several years. If you can’t find a NOS solenoid, then the best choice is to switch to the newer version with a six wire connector. There are articles on the net that explain how to convert.

I have my dual tanks working, but ended up buying a lot of ethanol resistant fuel line, and then have to keep all those hose connections tight. An alternative is to swap in a Blazer or Suburban tank in the back, and move your spare up into the bed. IIRC, they had three tank sizes, and the biggest was 40 gallons.

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I’m just going to put one tank back in on passenger side to make it easier. I see they have a 20 gallon on rock auto, have to check if it will fit in place of the 16. With a new tank and fuel pump up front and carb with a new canister I’m hoping that will fix all my gas problems and hopefully it won’t wreak of fuel like it did before. I was nervous of keeping it in garage with water heater on how it was before. I don’t think the system venting properly and cheap Chinese carb was blowing fuel thru vacuum ports. Hopefully it all comes together.

75gmck25 said:

Assuming you still want dual tanks - The six port solenoids with only a single power terminal have been unavailable for several years. If you can’t find a NOS solenoid, then the best choice is to switch to the newer version with a six wire connector. There are articles on the net that explain how to convert.

I have my dual tanks working, but ended up buying a lot of ethanol resistant fuel line, and then have to keep all those hose connections tight. An alternative is to swap in a Blazer or Suburban tank in the back, and move your spare up into the bed. IIRC, they had three tank sizes, and the biggest was 40 gallons.

Click to expand...

How hard is it to switch the wiring up to work with the newer 6-port? Can't be that complicated. I'm running dual tanks with in-tank pumps controlled by EFI and throwing together a schematic was pretty easy.

My 77 original 1 tank with aftermarket 2nd tank has a 1 wire switching valve and works flawlessly.
Seems far less complicated than the OE setup on my 86.
If you have good tanks no reason not to rig it back up like that. IMO. It’s one of the cool features of these trucks. And gas doesn’t last long in these things!

Grit dog said:

My 77 original 1 tank with aftermarket 2nd tank has a 1 wire switching valve and works flawlessly.
Seems far less complicated than the OE setup on my 86.
If you have good tanks no reason not to rig it back up like that. IMO. It’s one of the cool features of these trucks. And gas doesn’t last long in these things!

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I have to empty one of the tanks full of old fuel and inspect it. Now you got me thinking maybe I should run them both. I was just going to buy one new tank. But if the two I have are still good maybe I should put them back if they have that 1 wire switch. Did you run two hard lines across to each tank? Thanks for advice , is your 77 all stock?

Congrats on the new truck! Hopefully you get it sorted out.

Glad to see you are making progress! My comment early on is cause I am a " sort it out " guy. Meaning if the truck will not see a show not meant for daily drivers and workers, the economy easy version of making it safe is my choice. If plans were different, it would prompt a factory repair. When doing the easy route, I am mindful of not doing any thing drastic that can not be undone later if plans or owners change. Just an old guy rambling on. lol
Eric

jonbgood said:

I have to empty one of the tanks full of old fuel and inspect it. Now you got me thinking maybe I should run them both. I was just going to buy one new tank. But if the two I have are still good maybe I should put them back if they have that 1 wire switch. Did you run two hard lines across to each tank? Thanks for advice , is your 77 all stock?

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If the tanks don’t leak now, good chance they’ll be good for years to come. Especially if the truck is also pretty rust free.
On my 86 1 rusted out but from the outside where mud was trapped in the plastic shield. Whatever gets spilled between the bed and cab lands on top of the tank and makes its way down and trapped in by the shield.
The 77 is basically stock but the left saddle tank is a 70s era aftermarket tank in the factory location. (No idea why that was a good idea. It’s a heavy crusty square welded steel tank. Would have seemed easier and more economical to just use OE type parts since it only holds a couple more gallons than the stock tanks. )
It’s just a 1 wire solenoid 3 port valve, no return lines. And it’s new as of a few years ago. Toggle switch in the cab.
I do need to add some more steel line when I remove the bed.
But my point was it’s not hard to keep both tanks even if you don’t use an OE type switching valve. There are many options out there for dual tank valves. Manual or electric.