Stalls out after fill up
05-02-2024, 08:47 AM
#21
The vent line from the tank is a rubber line from the tank into the drivers side quarter panel. If you look around the rear tire you will see the steel line it hooks up with running along the top of the frame. Crawl under the rear quarter, drivers side. See the rubber line connected to the steel line. Unhook it right there. Just let that vent line breathe into the atmosphere.
Now, see what happens.
My charcoal canister got unhooked shortly after I bought my C3. It went along for the ride for 15 or 20 years until I finally yanked it out and binned it.
You do not need a charcoal canister. Cars from the 60's and older never had them. And they run fine.
some claim you'll get fuel smell in your garage without it. In all these years I've never had a issue.
Start by unhooking up in the rear quarter. That will eliminate any issues with the steel line and canister.
Now, see what happens.
My charcoal canister got unhooked shortly after I bought my C3. It went along for the ride for 15 or 20 years until I finally yanked it out and binned it.
You do not need a charcoal canister. Cars from the 60's and older never had them. And they run fine.
some claim you'll get fuel smell in your garage without it. In all these years I've never had a issue.
Start by unhooking up in the rear quarter. That will eliminate any issues with the steel line and canister.
05-02-2024, 08:49 AM
#22
Safety Car
Im running the advance on manifold vacuum as per factory. There is actually no ported vacuum source on this carb. I know because I looked. I've had these debates between manifold and ported vacuum. My 70 455 Buick runs very well on ported. This engine seems to like manifold but in this case, I have no choice.
The only data that really counts is the plugs. They have color and the it runs well so I know the engine is fairly happy.
Im running the advance on manifold vacuum as per factory. There is actually no ported vacuum source on this carb. I know because I looked. I've had these debates between manifold and ported vacuum. My 70 455 Buick runs very well on ported. This engine seems to like manifold but in this case, I have no choice.
The only data that really counts is the plugs. They have color and the it runs well so I know the engine is fairly happy.
05-02-2024, 09:18 AM
#24
05-02-2024, 09:21 AM
#25
Safety Car
Ironically my 74 starts to run like crap as my tank get low... I also found if I park it outside when it rains I tend to get water in my tank. Even with a different correct fuel cap and an unplugged drain hose for the filler area.
05-02-2024, 11:23 AM
#26
Le Mans Master
Im running the advance on manifold vacuum as per factory. There is actually no ported vacuum source on this carb. I know because I looked. I've had these debates between manifold and ported vacuum. My 70 455 Buick runs very well on ported. This engine seems to like manifold but in this case, I have no choice.
The only data that really counts is the plugs. They have color and the it runs well so I know the engine is fairly happy.
Im running the advance on manifold vacuum as per factory. There is actually no ported vacuum source on this carb. I know because I looked. I've had these debates between manifold and ported vacuum. My 70 455 Buick runs very well on ported. This engine seems to like manifold but in this case, I have no choice.
The only data that really counts is the plugs. They have color and the it runs well so I know the engine is fairly happy.
I'm looking forward to seeing what the problem turns out to be! I had similar symptoms, and the issue was 100% timing (and my own fault for believing a diagram, and not testing with a vacuum gauge).
05-02-2024, 01:04 PM
#27
Maybe something with the float in the tank? When it moves up maybe pinching something or disturbing something? Just throwing rocks here.
The length of time/miles between fill up and running smoothly might be important here. If it’s short, like a few minutes and a few miles, then not likely to be fuel level in the tank related, since the level doesn’t change that much in a few miles.
Boy these old cars sure like to play stump the mechanic, don’t they?
The length of time/miles between fill up and running smoothly might be important here. If it’s short, like a few minutes and a few miles, then not likely to be fuel level in the tank related, since the level doesn’t change that much in a few miles.
Boy these old cars sure like to play stump the mechanic, don’t they?
05-03-2024, 10:01 AM
#28
Heel & Toe
I had a similar problem with a GM car that had a Quadrajet. Seem the tank had alot of crap in it. Would plug the carb inlet filter, being it is spring loaded, it would plug than push open clearing somewhat to give fuel. (Not sure if that was happening) Off we would go. Fill it up, problem would return. Only thing that solved the problem was a new tank. With my 68 vette, you can look at 99% of the tank bottom. Just my 2 cents worth
05-04-2024, 12:04 PM
#29
Drifting
Not sure if the OP stated this yet...but how old and in what condition is the actual gas tank??? Rust, debris, unknown ufos??? On my '70 I have a newer tank. At one point, I had to remove and seal off the fuel separator valve (it was leaking), and also removed all return hoses and the charcoal evap canister up front. I use a vented gas cap now without issues. I don't have to pass smog tests, so no emission controls works. Regarding OP's problem, If it's not something wrong with the fuel tank, could be a new fuel filter and maybe a fuel pump is needed...Just things to ponder...
Last edited by RetroGuy; 05-04-2024 at 12:10 PM.
05-05-2024, 09:16 PM
#31
I think I figured it out. I think it was an excessive amount of water in the tank. Which seems to be a real issue on this car even after cleaning the crap out of that stupid drain hose and rubber gutter around the fill
WHat I did past couple of days was put like 4 or 5 gallons and running it to fumes. It got progressively better. The last fill, the problem disappeared. I think that there was an excessive amount in there and filling the tank just made it fall to the bottom of the tank. Filling it with 4 or 5 gallons and running it till it was on empty (I think) kept the water suspended and I able to burn it through the engine....I think.
We'll see. The car sits outside, so next rainstorm I'm going to put a rubber mat over the filler.
Sometimes I overthink stuff. Sometimes the simplest answers are the right ones.
WHat I did past couple of days was put like 4 or 5 gallons and running it to fumes. It got progressively better. The last fill, the problem disappeared. I think that there was an excessive amount in there and filling the tank just made it fall to the bottom of the tank. Filling it with 4 or 5 gallons and running it till it was on empty (I think) kept the water suspended and I able to burn it through the engine....I think.
We'll see. The car sits outside, so next rainstorm I'm going to put a rubber mat over the filler.
Sometimes I overthink stuff. Sometimes the simplest answers are the right ones.
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Bikespace (05-05-2024)
05-05-2024, 09:30 PM
#33
Le Mans Master
Excellent! So it was a quick solution, except for building a garage. 
05-05-2024, 11:45 PM
#37
Now to figure out the slight bind in the drive line on take off. Thinking it's got a tight u joint. Driveshaft looks like fun to remove....
05-06-2024, 02:45 AM
#38
Le Mans Master
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05-06-2024, 06:12 AM
#39
Safety Car
Same here. Sprayed brake kleen down the hose and used compressed air to blow it out. Still got water in the tank. A strong downpour overpowers the hose and backs up over the gas cap. I was going to try a new sealed cap to see if that would help but you pretty much answered that for me
Now to figure out the slight bind in the drive line on take off. Thinking it's got a tight u joint. Driveshaft looks like fun to remove....
Now to figure out the slight bind in the drive line on take off. Thinking it's got a tight u joint. Driveshaft looks like fun to remove....
05-06-2024, 06:14 AM
#40
Safety Car
Same here. Sprayed brake kleen down the hose and used compressed air to blow it out. Still got water in the tank. A strong downpour overpowers the hose and backs up over the gas cap. I was going to try a new sealed cap to see if that would help but you pretty much answered that for me
Now to figure out the slight bind in the drive line on take off. Thinking it's got a tight u joint. Driveshaft looks like fun to remove....
Now to figure out the slight bind in the drive line on take off. Thinking it's got a tight u joint. Driveshaft looks like fun to remove....
What do you mean by bind? If you mean a pop like the type you can feel pay attention to see if its worse when turning like in a driveway or parking lot. if so you need to add more posi additive for the clutchpacks in the rear end. Ive been there too and know 2 others that had the same issue.