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By 55charliebird - 7 Years Ago
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I AM PUMPING 80 PSI OF AIR INTO THE FUEL LINE THAT GOES FROM THE FUEL PUMP, REARWARD TO THE FUEL TANK. MY ASSUMPTION IS THAT THERE ARE NO CHECK VALVES OR SHUTOFFS ANYWHERE IN THAT LINE. THE FACT THAT IT IS CLEARLY NOT COMPLETELY OPEN TELLS ME THAT THERE IS SOME DEAD GASOLINE WHICH HAS FORMED INTO A BLOCKAGE. I SHOULD BE ABLE TO HEAR AIR RUSHING INTO THE FUEL TANK AND THE COMPRESSOR SHOULD CONTINUE TO RUN CONSTANTLY. MY QUESTION IS " SHOULD THAT LINE BE COMPLETELY OPEN W/O ANY RESTRICTIONS? IF ITS VARNISH OR GUM, HOW DO I GET RID OF IT W/O REMOVING THE LINE.
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By YBLOCKEREDH - 7 Years Ago
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Is there also an electric fuel pump between the tank and mechanical pump?
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By charliemccraney - 7 Years Ago
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Given the age of the vehicle, it's not safe to assume anything. Previous owners do crazy things. Look at the line and make sure there are no added components, like a shut off valve, that would easily explain a blockage.
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By Hoosier Hurricane - 7 Years Ago
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Make sure the gas cap is off when you blow into the line. No way could the tank contain that much pressure. Even with a vented cap, the vent probably could not flow as much air as your compressor could put in.
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By Dobie - 7 Years Ago
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Check for rubber sections under the car. A PO may have replaced the fuel line with generic line from an auto parts store. Nothing wrong with that but there may be one or more rubber sections that have collapsed internally, blocking the line. Especially look where the line goes over the frame at the left rear wheel. It's not possible to install a solid OE fuel line without lifting the body up off the frame and many people don't go to that trouble, they just splice in a rubber piece in that area.
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By 55charliebird - 7 Years Ago
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No electric fuel pump installed.
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By 55charliebird - 7 Years Ago
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No shut off valves installed.
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By 55charliebird - 7 Years Ago
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Tank cap totally removed. That's where I listen for air rushing into the tank.
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By 55charliebird - 7 Years Ago
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Great thought. I will investigate that possibility. Thanks.
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By MoonShadow - 7 Years Ago
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There should be a rubber hose connection at the tank. Take it off and blow through with both ends of the gas line open. If no air its in the line. If air its in the tank. Some tanks get a lot of sludge or varnish in them eventually the pick up sock filter (if you have one) gets clogged. Having the fuel line off at the tank you should get gas coming out of the tank so you need a catch pan. If nothing comes its the tank. Matter of following the problem to both ends.
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By Joe-JDC - 7 Years Ago
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The old rubber hose doesn't collapse, it deteriorates/expands internally with the alcohol in today's gasoline, and shuts off the fuel flow. Same thing happens with brake lines where someone changes the brake fluid to DOT 5, and the hoses are made for DOT 3 or lower number. The rubber isn't compatible with newer fuel, or in the case of rubber brake hoses, synthetic brake fluids. You will need to buy new fuel hose that is made to be compatible with E-85, or blended alcohol/methanol/gasoline. Joe-JDC
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By Lord Gaga - 7 Years Ago
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No problems with DOT 5.....25 years!
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By KULTULZ - 7 Years Ago
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Rubber fuel line will collapse if old and spongy with a mechanical fuel pump (vacuum collapse) as will a lower radiator hose if weak. Maybe replace all sections with ethanol rated (low pressure EFI) rubber tubing.
"There should be a rubber hose connection at the tank. Take it off and blow through with both ends of the gas line open. If no air its in the line. If air its in the tank. Some tanks get a lot of sludge or varnish in them eventually the pick up sock filter (if you have one) gets clogged. Having the fuel line off at the tank you should get gas coming out of the tank so you need a catch pan. If nothing comes its the tank. Matter of following the problem to both ends"
GOOD ADVICE ABOVE!
Isolate the fuel line from the pump/tank. Blow through it with air. If no air exits the opposite end (blow in each end alternately) squirt some carb/choke cleaner into and follow with a little air pressure. Wait see if that clears the obstruction. If not after a few tries, the line itself must be replaced.
If the line itself is completely blocked, it might be a good idea to also drop the tank and have boiled out. The residual varnish left in the tank will be dissolved by the future methanol and keep fouling the fuel system.
Use STA-BIL (two products offered) with a fuel system open to the atmosphere (open vent) with E-10.
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By Joe-JDC - 7 Years Ago
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Hate to disagree, but when you cut an old fuel line apart, it will be completely dried out, or it will be swollen, and soft inside if it has been subjected to alcohol, E-85, or ethanol. Same with brake lines on most of the Ford products from the early '80s where the rubber hoses to the rear axles deteriorate and close off brake fluid going to the brake wheel cylinders and drum brakes. If a vehicle sits any length of time, the rubber deteriorates and will burst with high brake pedal pressures. Had to replace too many not to see it as a real problem. Joe-JDC
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By KULTULZ - 7 Years Ago
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"but when you cut an old fuel line apart, it will be completely dried out, or it will be swollen, and soft inside if it has been subjected to alcohol, E-85, or ethanol."
Yeah, and they (as you describe) are subject to collapse as a result of suction/vacuum from the mechanical fuel pump, cutting off fuel flow ... right?
There are several types of hoses, pressure, vacuum, oil resistant rating...
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By PF Arcand - 7 Years Ago
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. Just a note on Fuel Stabilizers; Stabil 360 is the product intended to deal with Ethanol. On fuel, I'm recently advised that all 92 octaine or higher does not contain Ethanol, at least in Canada..
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