Broken hearted kid and fuel system

[Grit dog]

Gotcha. So we replaced the fuel pump with the exact one that was in it before. There are two types for his truck, one short and one tall. It had the short one on it.

We can put the line from the fuel pump to the carb in a bottle of gas and it will run off that gas til empty. It will also run if we pour gas down the choke side of the carb and soon as it’s gone, it stops. It seems like it’s surrounding the fuel pump. When it’s taken out of the equation, everything works.

Ok. So can you pull fuel from the tank to the fuel pump?
On second thought idk if there’s a check valve preventing the blowing bubbles into the tank test. I don’t think there is.
But using a vacuum extractor or a cheap electric pump will verify for sure if there ls not still a problem upstream of the fuel pump (back to the tanks).
Do those couple things and likely isolate the problem to the fuel pump or cam lobe.
Fwiw short or long pump doesn’t matter. I was just not certain if there’s different lengths of push rods between years or big/small block.

You’re close to gettin it on the road! Wish you were closer physically I’d give you a hand.
So who in here lives close to Roanoke Rapids? Wherever that is? I bet @medic503 has a cold 12ver for someone who can spend a couple hours diagnosing this in person with him!

 

[medic503]

Ok. So I’m here now. When we put the fuel lines in a gas tank running to the pump, it runs fine. This means the fuel pump and carburetor are working. Correct? The problem comes when I connect it to the real tank. Then it won’t pull up anything. So based on what I can figure from what everyone is saying, there’s an air leak between the tank and the fuel pump. I can handle that. We’re gonna try to find the bed bolts so we can take off this side and look at the valves and sending unit better. I will report back in a little while.

 

[medic503]

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[medic503]

That’s the fuel filter that we took out with the crud on the outside of it.

 

[born2Run83]

Are the fuel pickups that mount to the tops of the tanks the original? I had a similar issue and I noticed when I pulled the pickup unit out, there was a small plastic part inside the pickup housing that dry rot/rattled loose over time and was causing issues with fuel to get from the tank, into the actual fuel line to feed the engine.

 

[squaredeal91]

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That filter don't look plugged up dirty visually, What I'm seeing is it looks sucked up like it is plugged?

 

[medic503]

I can’t add a video but we put the supply line in a bottle and after 20 seconds of straight cranking, I had a capful of fuel. Runs fine off a gas tank. I’m assuming there’s an air leak somewhere. Gonna run to the store and get a coupling and try hooking it directly to the gas tank and bypassing the selector valve. I’ll update asap.

 

[medic503]

This is the weirdest **** I’ve ever experienced in my life. Ok so, went and got the clamps and things to run directly from the fuel tank. I hooked the supply line (the big one) up to the fuel tank and then directly to the fuel pump. Then from the fuel pump (now the threaded one) to the front of the carb. Tried starting it and nothing. I disconnected it and a little fuel spit out and damn if the truck didn’t start the truck was running without the fuel supply line attached. I’ve got to find a way to add videos cuz I can’t believe it. There was no fuel coming from the supply line Just a bunch of smoke from the exhaust and some silver pipe on the left side. As long as he kept his foot on the throttle, it kept running. Soon as he took it off, it would cut off. Then he had to play with it a little bit and it would start right back up. How does a truck run without the fuel line attached?

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[medic503]

We have stopped for the night but any advice is much appreciated. I really want to get this figured out. Gonna go back later this week and see what we can do.

 

[Travlr]

Ok yall, Ive got a situation and I cannot figure it out.

- When he first got the truck, the carburetor was taken off and given to a mechanic to clean. He cleaned it and did a few other things to it and we got it back. Wouldn't work.
- bought an
Ran fine off a bottle.
That is literally the only part of the fuel system left that had no been replaced (except for the metal lines) on the passengers side. Still wont start.
Just an FYI, all of the work was done on the passengers side. We have not touched the drivers side.
d installed a new fuel tank selector switch, didnt work.
- dropped the passengers side tank and cleaned it out, put in a new fuel sending unit. didnt work

Have you tried flipping the switch to use the left tank? Could you have some crossed wires at the fuel selector switch? (Are you talking about the switch on the dash or the valve under the truck?)

Put some gas in the left tank and see what happens. The switching system to change tanks has always been finicky on some trucks. Or take some hose and bypass the valve and make a direct connection to the right (passenger side) tank.

And don't panic and go throwing money at a new carburetor just to see if something will stick. Quadrajets are great carbs, reliable and easy to work on as long as the throttle linkage isn't worn out and needs to be rebushed. If your problem is no fuel to the carb... then your problem isn't the carb.

 

[medic503]

Have you tried flipping the switch to use the left tank? Could you have some crossed wires at the fuel selector switch? (Are you talking about the switch on the dash or the valve under the truck?)

Put some gas in the left tank and see what happens. The switching system to change tanks has always been finicky on some trucks.

I hooked it directly to the tank. I bypassed the selector valve. I don’t understand how the fuel line can be disconnected but it still run. The switch went directly into a wiring harness that was old looking so I’m assuming it’s original to the truck. I figured it was done right since it was factory. I will get him to try to change tanks tomorrow and see what happens. I have to work so he will be by himself. I will report back when he does it. Any other opinions appreciated.

 

[SquareRoot]

Methodology. It ain't rocket science.

 

[rusted nuts]

Yes. I can put the carb supply line in a bottle and it runs fine. But when I connect it back to the fuel pump, it won’t do anything.

then it's not the carb.

 

[Randy and Easton]

@medic503 stay with it. Y’all are so close! I say electric fuel pump as suggested above. Cheap and easy fix.

On a side note.. don’t quit! Easton bought his square with his money at 14.. we worked on it for 2 years to get it where it is today and I can’t tell you the number of times I wanted to quit and sell that thing. The folks here saved me more times than I can count and in the process, made me look a lot smarter to my kid than I actually am! Now at 17, he has his badass daily driver! It still has things here and there to work on.. but the life skills he learned by doing it (with everyone here!) you can’t put a price tag on any of it. It was (still is) something we as a father and son will never forget!

I’m following this thread .. please keep us posted.

Randy and Easton

 

[AKguy]

Any possibility there is a venting issue?