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I have posted this on a few forums so if you are seeing this again, my apologies.
I had a fuel smell coming from the passenger rear quarter panel and after pulling the quarter. I noticed that the lower return line was loose, crimped, and gas was sweating onto the bottom of the expansion tank. When I pulled the line off, fuel constantly spewed out of the tank. When I pulled the hose closest from the filler return, no fuel flowed. So I know the return hose is collapsed and has to be replaced.
The question I have is why is fuel flowing out of the expansion tank? When I pulled the Fuel Pump solenoid and cranked over the engine it was a no start meaning the system depressurized which is normal. There were dribbles of fuel coming from the expansion tank. When I opened the filler cap which should have released any excess pressure. The fuel started full flow spewing again. When I closed filler it stopped. It seems like it is syphoning. Is that normal?
Thoughts on what is going on? Is it a faulty check valve at the inbound line? I'm trying to get this truck ready for ANARC next week but not so sure if I can't get this sorted.
Fuel Expansion Tank Leak from lower collapsed return line.
Update: I think due to the return hose being collapsed the fuel was under suction and when I pulled the hose off it was syphoning. I pulled the 3 breather lines at tank level and then removed the return hose and let it drain fully - about 1 gallon of fouled fuel. I cut new 1/4" hose and bent the fuel filler vent pipe to about 45 degrees from 90 degrees. I think the 90 degrees makes the line have to be longer and hold much more fuel than necessary in the expansion tank and not able to drain back - also the reason the hose kinked.
Note: It is best to unbolt the tank and clean all the dust and grime out off the inner wall and do any rust mitigation if necessary before putting the tank back. The area was thoroughly coated in black undercoating on my truck so it only needed a slight touch up at the seams before I reinstalled the tank.
Out with the old:
Fuel Expansion Tank problem on 1990 RRC
