Diego53
Active Member
Fuel line is bubbling air into the filter and won’t fill up enough to stay running or even start half the time .. what’s the best method to find the leak ? Btw I have a 65 dart
Any tricks for finding a leak in fuel line ?
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pishta
I know I'm right....
it should not boil if the tank is vented and there are no external heat sources...65 tank has a non vented cap and a vent pipe up under the fender at the pipe head. its clipped to the body and points down. can see it from the trunk : small 1/4 tube that can be used as an air source or cap it. if you can (low) pressurize it with a bike pump or even a inflated balloon held on the end go under the car with a spray bottle of water and soap and gently squirt the fittings with a stream of this. if a bubble starts to form , there is your leak. I'd start at the rubber hose from the sender.
pishta
I know I'm right....
its vented in the filler pipe.
There are not too many points you could be getting air into the system
But 2 thru 4 might syphon fuel out of the tank and you would have a fuel leak that would be noticable
The fuel pump might have a leak before it is pressurized but I would expect a syphon leak there too.
Once the fuel is pressurized you would have a fuel leak that would be noticable.
So if you have no visable sighs of a fuel leak my bet is the pickup tube in the tank has a rust hole or a crack.
Or as others have said your fuel is vaporizing in the lines.
I had a similar issue, not that extream, but I could watch my clear fuel filter go empty, engine rpm drop then it would refill.
And if the engine was really hot it would get fuel starved on light to medium acceleration.
All this has been solved by using non alcohol fuel.
- Fuel pickup tube in the tank might have holes above the sock filter.
- The hose between sender and body tube
- Body tube
- Hose between body tube and fuel pump
- Fuel pump
- Hard line from fuel pump to filter
- Hose between hard line and filter
- Filter
- Hose between filter and carb hard line
- Hard line to carb
- Any of the misc fittings along the way.
But 2 thru 4 might syphon fuel out of the tank and you would have a fuel leak that would be noticable
The fuel pump might have a leak before it is pressurized but I would expect a syphon leak there too.
Once the fuel is pressurized you would have a fuel leak that would be noticable.
So if you have no visable sighs of a fuel leak my bet is the pickup tube in the tank has a rust hole or a crack.
Or as others have said your fuel is vaporizing in the lines.
I had a similar issue, not that extream, but I could watch my clear fuel filter go empty, engine rpm drop then it would refill.
And if the engine was really hot it would get fuel starved on light to medium acceleration.
All this has been solved by using non alcohol fuel.
Done this so many times in 60 years on older than 65 and newer than 65, I said 15 for the novice, we just did the air hose at full 100 psi but we knew when to let off. Do you have your mask on?
Neither of you are helping the OP with this witty banter.
Agree to disagree, if OP takes bad advice that is on him for not doing more research.
Agree to disagree, if OP takes bad advice that is on him for not doing more research.
Oh really, pressure in the line forces stuff out the last time i checked. Works on tires, brake lines, radiators, hoses, heater hoses, need more?
80fbody
Well-Known Member
Ethanol fuel eats up rubber. If you have any rubber sections, I’d start by replacing them. Typically though fuel usually leaks, not pulling air. That’s a new one to me. I’d question my fuel pump as well since that has a rubber diaphragm typically.
67Dart273
Well-Known Member
THis is not "witty banter" I guarantee you that only a few psi will bow a tank out and deform it. That IS trying to help the OP if he is unaware. Dana I know you are a smart guy. Estimate the surface area of the bottom of the tank in rough figures, and figure out how much total pressure 5psi will put on that amount of surface. "Let's say" it's 2 ft square, just for an example. 24x24= 576 square inches. If you put the example 5psi in that tank, that's 576x5= 2880 lbs of force!!! I am not going to "crawl under there" and measure the tank just to prove a point.
You don't need to tell me, 14.7 psi atmosphere can turn it into a pancake if you put a vacuum on it.
Back in the 80's a kid got killed in a truck shop I went to. They had a 55 gal barrel of oil and it had a reg on it, guys would plug in the air hose and oil would get pumped out into the can they used to dump it in the motor. Some jerk took the reg and the kid plugged the hose on and it blew the bottom out of the barrel and the lip on top of the barrel hit him under the chin and cut his head in half. He died instantly and the barrel hit the roof of the shop. It put the guy out of business.
Agreeded it was the amount of pressure that was bothersome.
Maybe we can move on and help the OP with his issue.
Hole in the fuel pump diaphram??...
Then there would be fuel in the oil. Unless slant....
One of the principles of hydraulics. 5 PSI is 5 PSI weather it’s a beer can or 55 gal drum!
The square inches of a beer can is a lot different than the square inches of a 55 gal drum.
But 5 PSI is 5 PSI.
Your confusing pounds per square inch with volume.
Exactly Roy,
beer can is 2.6" diam
55 gal drum is 24" diam
2.6xpi is 8.168
24xpi is 75.4
8.168 x 15psi = 122.5 pounds of pressure
75.4 x 15psi = 1131 pounds of pressure
Your not making sense. I'm making one statement. If you fill a 13" tire to 5 PS1 and you fill a airplane tire to 5 PSI, they both have the same Pounds per square inch! I'm not saying the volume in a airplane tire will fit in a 13" Valiant tire.
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