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OK here's an interesting one. Getting my 89 with 244000 miles ready for the dreaded California smog crap. (I'm bound and determined to get it to pass). have gotten everything sorted aside from an evap system leak. Smoke tested it last night. Found the leak at the fuel tank seam just above the spare tire. My question is... How in the f*** is there smoke coming from there but I'm not leaking fuel? I had just filled the car up that morning (full tank of gas). The "leaky" seam in question is completely dry.
I don’t think there is a way the seem could leak without leaking fuel. Is it possible that one of the rubber hoses or lines under the rubber boot are leaking and smoke is billowing down from that area. It’s an easy check to remove fuel door and rubber boot.
I don’t think there is a way the seem could leak without leaking fuel. Is it possible that one of the rubber hoses or lines under the rubber boot are leaking and smoke is billowing down from that area. It’s an easy check to remove fuel door and rubber boot.
Already checked that. Was underneath the car with a flashlight and mirror. It's pouring smoke out of the seam but no fuel.
The tank has an inner liner. The fuel filler and sender plate bolts thread into inserts in the liner around the opening. If a void develops between the metal outer "tank" and the liner around the sender opening, smoke would come out of the seam, but if the liner itself isn't compromised, there will be no fuel between the liner and the metal, and thus no liquid leak at the seam.
You're trying to pass smog. I'd try smearing something on the seam where the smoke-leak is to seal it.
Also smoke-test the gasket and bolts around the sender plate. I presume that you are introducing the smoke at the front of the car, so you are testing the plumbing including the connections to the tank?
If there are no smoke leaks, including at the seam, it should pass the tank test for CA smog.
EDIT/ADD: I looked at your picture of the tank. The EVAP connections are not on the sender plate where I thought they were. If there is a void between the liner and the EVAP connections, that's your vapor leak. That can't be fixed without replacing the tank, other than by sealing the seam with epoxy or something stout.
The tank has an inner liner. The fuel filler and sender plate bolts thread into inserts in the liner around the opening. If a void develops between the metal outer "tank" and the liner around the sender opening, smoke would come out of the seam, but if the liner itself isn't compromised, there will be no fuel between the liner and the metal, and thus no liquid leak at the seam.
You're trying to pass smog. I'd try smearing something on the seam where the smoke-leak is to seal it.
Also smoke-test the gasket and bolts around the sender plate. I presume that you are introducing the smoke at the front of the car, so you are testing the plumbing including the connections to the tank?
If there are no smoke leaks, including at the seam, it should pass the tank test for CA smog.
EDIT/ADD: I looked at your picture of the tank. The EVAP connections are not on the sender plate where I thought they were. If there is a void between the liner and the EVAP connections, that's your vapor leak. That can't be fixed without replacing the tank, other than by sealing the seam with epoxy or something stout.
Picture is just a generic picture snagged from parts geek after I looked at the cost of new tanks.
And yes we smoked from evap purge valve to the back and only leak was at that seam. Was even close to the .040" allowance. And my teacher said the same thing. Put jb weld on it and it should bring the tolerance down enough to pass
What the fuel?
