FormulaEngland

Was out in the car last weekend and made a 150 mile round trip and when I was almost home there was quite a strong smell of fuel lingering around.

Then when I was out in it again last night on a much shorter trip it was there as well.
This is only the second time I've noticed it, I did a 260 mile trip in it a couple of weeks ago and no fuel smell at all.
Any ideas why? I cannot see any fuel leaking anywhere from the tank.

BovineZro

iTrader: (11)

I can think of two potential causes; others may have more suggestions.

Cracked fuel neck - this was causing mine to smell of fuel as well. I bought a replacement tank, fixed the problem. The holes are very tiny; I was barely able to see them in good lighting once I got the tank out of the car.

Broken/missing vent valve - this allows the tank to equalize pressure. If it was somehow damaged or blown out it might let fumes escape constantly (or maybe only when the tank is hot, etc).

Is the smell localized in one area, or does it just sort of permeate the whole car?

FormulaEngland

By those two descriptions I'd say it's the latter. It seems to be localised toward the rear of the drivers side. When the cars cold it doesn't smell of fuel. I'm guessing yours smelt of fuel all the time rather than when the tank/engine is warm?


If it is the vent valve, how much are they and how much of a ballache is it to replace?

BovineZro

iTrader: (11)

Yeah, mine reeked of it, especially when parked. Wasn't too bad while moving.

The valve is located on the body in front of the rear axle, towards the driver's side (so it matches the location of your smell). Not too hard to get to if you have good jackstands; I was able to reach mine with the car about 1.5 ft in the air. I didn't replace it at the time but it's on a section of flexible hose with hose clamps. You could probably get away with cutting it off if the clamps are in bad shape and using a new clamp with the replacement.

This thread has some pictures and info that might be helpful (it's not really the same problem but he's working in the same area): https://www.thirdgen.org/forums/tpi/...eat-blues.html

I'm not sure if a factory style vent valve has any benefits over the Summit replacement, but if you are replacing it anyway may as well try it. I haven't priced one but according to the article it's $15.

greenyone

iTrader: (1)

The Summit valve is a "roll-over" safety valve. Don't confuse this as a direct replacement for the factory tank vent valve which has a spring/diaphram that allows the tank to breathe under different pressure conditions. The summit valve is an always open valve. It's made to be installed upright so that if you are unfortunate enough to roll your car upside down, the weight of a small check ball closes off the valve preventing fuel from pouring out of the tank.

Search here on TGO for cleaning your factory vent valve. Some guys have had luck carefully taking it apart and cleaning our years of road grime that brings it back to life. The factory valve is a discontinued part that is not available in the aftermarket either. So this may be your best bet. Otherwise look on ebay, salvage yards or the classifieds here on the forumn for a good working used one.

Another simple thing to look at is the gas cap itself. There is a rubber o-ring in there that get perish over time. So the smell could be as simple as a bad seal between the cap and filler neck. A new gas cap would fix this.

BovineZro

iTrader: (11)

This is good to know! Thanks for the additional clarification.

Matt trans am

Most likely too much pressure in your gas tank. Open the gas cap and see what comes out. Very regular occurence in these cars