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Well, I'm at the point of working the bugs out mechanically. After sitting for a few days, I have a problem with vapor lock. The problem apparently is between the fuel pump and the in line filter I installed about 8-10 inches upstream from the pump. The symptoms are no start, fuel pump running continuously. Remedy is to loosen the line between the pump and the filter, then run the pump till gas runs out. After re-tightening, everything runs just fine. Whassup?
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Vapor lock on BJ8
- Thread starter Cutlass
- Start date
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healeynut
Jedi Knight
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Sounds to me like your filter is full of crud. Very easily done, very quickly - these tanks on our old cars can accumulate rust rather fast if they sit for too long.
Try replacing your filter with a new element - if this is it, you may need to do this two or three times until all the rust is out of your tank.
Try replacing your filter with a new element - if this is it, you may need to do this two or three times until all the rust is out of your tank.
GregW
Yoda
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Hi Cutlass,
A couple things come to mind. How do you have the filter oriented? If the output to the engine is higher than the input, the low pressure pump might not be able to force gas past the air bubble. If you haven't, check all the fittings from the gas tank to the output of the filter. Did you use a 5/16" filter and hoses? That size is getting hard to find these days, 3/8" being more common.
A couple things come to mind. How do you have the filter oriented? If the output to the engine is higher than the input, the low pressure pump might not be able to force gas past the air bubble. If you haven't, check all the fittings from the gas tank to the output of the filter. Did you use a 5/16" filter and hoses? That size is getting hard to find these days, 3/8" being more common.
red57
Jedi Knight
Offline
Hi Cutlass,
A thought. Usually once the system is flowing fuel any air should be purged and just fuel flowing. For an air bubble to form after you have it bled of air, you are getting air in the system somehow. I would look at the connections at the tank and the suction side of the pump. You may have a small leak in one of those fittings and when you turn on the pump it may be sucking a little air in causing the air bubble in the filter. I have had this happen. You may not have any fuel leakage because it's on the suction side - if you had a leak on the pressure side you would have a fuel leak evident.
At the other end make sure the float needles aren't sticking. If they are sticking it may be that your pump is comressing the air and not delivering enough pressure to open them up for fuel to flow - air compresses, liquids don't. Again though, if all things are right no air should be getting into the system.
Good luck
Dave
A thought. Usually once the system is flowing fuel any air should be purged and just fuel flowing. For an air bubble to form after you have it bled of air, you are getting air in the system somehow. I would look at the connections at the tank and the suction side of the pump. You may have a small leak in one of those fittings and when you turn on the pump it may be sucking a little air in causing the air bubble in the filter. I have had this happen. You may not have any fuel leakage because it's on the suction side - if you had a leak on the pressure side you would have a fuel leak evident.
At the other end make sure the float needles aren't sticking. If they are sticking it may be that your pump is comressing the air and not delivering enough pressure to open them up for fuel to flow - air compresses, liquids don't. Again though, if all things are right no air should be getting into the system.
Good luck
Dave
R
RonMacPherson
Guest
Guest
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I read this thread, and Dave's description is the most logical. For an air bubble to reappear air has to be coming in from somewhere. Check the fuel pump and fittings. Make sure old hose has been replaced..