Yesterday, I drove my recently acquired '76 308 back from my mechanic who just checked out my mixtures (and who raves about how strong mechanically the car is).
This sounds odd, so bear with me - some facts:
1. The car runs as strong as new with great compression.
2. All fuel hoses were just changed (5 months ago) on this car.
Here is what my friend and I observed on the way home from the shop today (he was following behind me in his car):
After filling the fuel tank (topped it off until pump clicked) I noticed a smell of gas in the cabin - I naturally thought it was me as I had just gotten some on my hands.
During a sharp right-hand-turn on-ramp, my friend noticed some liquid spewing out of my left hand tailpipe region - he immediately notified me(we were in contact with each other via handheld radios) but I wrote it off as being from condensation as the car was not completely up to temp and he did not notice any steam or smoke. at this time, I smelled a stronger odor of gas, especially after making the turn.
This event happened again during the next right hand turn, and again my friend just observed liquid with little smoke - he also smelled gas from inside his car. I immediately pulled over and shut down.
The engine bay itself did not smell of fuel (only the cabin). I could not see anything leaking anywhere. I figured that no way would fuel be pouring from the exhaust as it would vaporize or catch fire first. But, the left tail pipe had a whitish stripe inside - as if something did indeed run out of it. Again, no leaks could be seen and the car was runnning better than excellent, all gauges "in the green".
After a while (after some fuel was used), this event did not happen again - my friend was watching me like a hawk. I made other turns and no liquid could be seen. Although, I still smelled gas during turns.
My questions are:
Could I have overfilled the tanks and during a right hand turn, fuel was sloshing into the left tank and overflowing somehow?
Is there a overflow tube somewhere and my friend could have mistaken it to be coming from my exhaust (but there was a tell tale sign, the stripe, in the exhaust that indicated something had ran out of it)?
How could it be possible for fuel to run out of an exhaust in a stream like my friend observed?
Of all the wierd problems I have heard, this one takes it......
To best answer your question...and concern, I'll start by questioning the statement "All fuel lines were replaced..."
Based on your detailed description, there are two areas I would look at now...before driving the car another mile.
1) The fuel filler overflow hose, on the filler neck. Verify it's condition, tightness...and that the hose is long enough to exit a few inches below the lowermost frame rail. This hose likely is the culprit.
2) The fuel tank vent hose...Rarely changed. This usually is a semi-clear 13mm hose which connects the top of each fuel tank to the other. It runs from the top of the tanks across the firewall. Verify it's condition and tightness of connections.
This is not a wierd problem...or one that should be taken lightly, as the likelyhood of fire is real. Fuel and the proximity of a hot exhaust manifold don't play together very nicely.
I suspect here's what happened...
You may have overfilled the tanks (for reference, they are connected under the car by a cross-over tube.)
The excess fuel...instead of streaming on the ground, ended up in the frame, or lower wheel well fibreglass area...and when you pulled away...it worked its way out by the body opening for the LH exhaust. (The overflow tube exits on the LH side of the car)
Thank you for your detailed explanation. I have the workshop manual and its diagrams. I will check everything. I know this is a dangerous situation and will not drive the car another mile.
"The fuel filler overflow hose, on the filler neck. Verify it's condition, tightness...and that the hose is long enough to exit a few inches below the lowermost frame rail. This hose likely is the culprit."
Are you saying the fuel filler hose has another overflow hose connected to it which drops down below the frame rail? Should I see a small hose in this area?
Some of my evaporative emission lines are original (the braided lines). The vent line that runs on top, connecting the two tanks, looks to be original and probably should be replaced.
Anthony,
You're car likely is a bit different than my pre-smog BB. Either way, there is a fuel overflow hose...possibly your doesn't exit to the ground. Follow, the line off the filler neck...sounds like it might go to some sort of evaporative canister (versus the ground). These are the lines/hoses I'd be most concerned with. If there is a vent line, it too should be below the chassis frame rails. Sometimes, it is just visible, when looking in, just in front of the LR wheel.
Large Filler Rubber Hose Cracked/Loose Clamps/Dislodged
Lower Gas Tank Hose to Pump / Fuel Filter/ Fuel Pump/ Fuel Pump Hose to Carbs leaking .
and on the right side- fuel return hose to tank and/or Carbon Canister hoses leaking (especially under Cowl on Top of Tank.
Check all those areas while you're at it.
You can refill tanks from can at home and jack up left side of the car with a floor jack at the jack point to see if the problem can be induced while sitting, instead of chancing driving around.
In the parts manual's diagram of the fuel system, a "calibrated" valve is shown at the end of a very small tube, just above the filler neck tube, slightly below the fuel cap. Is this in fact a fuel overflow tube/valve? Does this valve allow fuel to exit during an overflow situation?
that's correct...this is to prevent overflowing fuel from spilling near the exhaust. It is supposed to exit near the bottom of the Left Fuel Tank in front of the LR tire.
Well I was under the car today and I am not very confident about what my problem is.
The "overflow" tube I see looks like it only catches any spilled fuel from the tray where the gas cap is. I did not spill any there at the time this happened and the cap was on properly and is a correct cap.
Now, this "calibrated valve" - I did see it. It was there just like the parts book displayed it (can you believe it?!). It is a valve just sticking out of the metal part of the filler, slightly above where the top of rubber filler neck hose is. It is pointing to the rear of the car, but has no hose attached to it that would carry overflowed fuel. It's just a small stubby valve. I can not find a description of this anywhere, just a statement that says "..to prevent fuel outlet" ???. Why would there be a valve here then in the first place!!
Does anyone know what this valve does? If it is unload excess fuel - it does not dispense it safely, as fuel would pour over the top of the tank. ?????
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Hi,
Yesterday, I drove my
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