Raw Fuel Coming Out of The Evap. Cannister Lines

[ckcarr]

Never seen this before. But for some reason I have fuel coming out of the evap lines that enter the passenger side engine bay. Not just a drop or two, but a significant amount,

Two things I did to the vehicle ('78 928 manual) 1) New Bosch fuel pump a year ago. 2) The aftermarket fuel gauge in tank (from 928SRUS).

I will retrace all my work and lines, but anyone know anything about this ever happening? And where would the proximate starting cause be located?

Thanks!

[honerboys]

did you just fill it up? - maybe gas expanded and backed up into those lines?

[ckcarr]

No, there's only around 6 gallons in the tank.... I'm just going to trace the lines from back up to the front, probably this weekend...

[Monkey Wrench]

when the tank gets warm the air inside it expands creating pressure, the air with fumes exits through and collects in the charcoal cannister, there should be a vacuum line to the intake area.

, when the engine runs it has this controlled leak constantly sucking through the cannister. Id check that lne it might be plugged and not allowing the fuel to be burned by the engine. I found the one in my ford van very loose where it went from a rubber to hard line and there i had a cvacuum leak, a vacuum leak will upset the idle, it shoudl be a closed circut back tot he tank.

the system prevents fumes from escaping to the atmosphere at the cap and the cap should seal.. I think it also allows air in.

if the air cant; get in to replace any fuel you use you can run out of fuel as the pump is fighting a vacuum in the tank.

if you remove the cap and feel either an inrush or outrush of vapors it means something is wrong.

you might have a kinked line. I dont think the amount of fuel in the tank is a big factor. maybe something is plugged up and not allowing vacuum to suck on that line to the cannister.

maybe try pulling the line from the intake off near the cannister, start your car put your thumb over it it shoudl be sucking to evacuate the cannister. or maybe it cant; draw fuel as the cannister is sealed by a kink in the line in the run back to the gas tank. if you dont have any vaccum on that line Id follow it but maybe you could clear it with a shot of carb cleaner , maybe its plugged where it sucks from, something connected to the intake manifold. it might end up as a fairly small hole where the vacuum is conducted from the manifold.

while vacuum leaks are generally considered bad, the desighn allows for this air leakage in normal operation. if you have a hose split or off maybe it would idle poorly, at WOT I dont think its going to care much as its involving less of the air fuel precentage ratio, at idle , its more sensitive.



just a funny story..
I once had a VW bug, it used the spare tire to pressurize the windshield washer bottle so no pump was needed, just a valve. well being young and stupid I sonmehow got that connected to the charcooal cannister, it filled it with water and the engine didnt run so well with my new fangled water injection system. ;-)

old cars dint need them and they also had troad draft tubes for crankcase ventillation there were to help the environment .. Id try to keep it original. its a bit of unnecesary weight but best to burnthe fumes and keep it as it was designed.

at one point we had pollution testing and youd fail if the cap leaked, they had special testers to check that valve in the gas cap.