Hello everyone, I have a 98 Jimmy and it is leaking fuel from the vent solenoid above the
spare tire. This only seems to happen on very warm or hot days and also after driving for 2
hours or more. This first occured last fall on days that the temperature was 80 or above. I changed the solenoid and blew air through the lines looking for a blockage but found none. I also changed the gas cap. Needless to say it never happened again until the last couple of days.

My question is does the pressure sensor on top of the tank regulate the pressure or only monitors it? Or do I need to look elsewhere. Thanks, Jeff.

 

Do you try to fit as much gas as possible when filling up or do you stop at the first click? I've been told that overfilling can cause gas to collect in there.

 

I just fill it with gas until it clicks off. The problem usually occurs when the tank gets down to 3/4 tank after running for 2 hours or so. The gas odor gets strong and there is gas dripping from the spare tire.
Today when it happened I loosened the cap and there was definetly a pressure release. I drove it for about 2 more hours with the cap loose, periodically checking for dripping gas and didn't see any after loosening the cap. There was still a fairly strong odor.

 

Well, I tried changing the purge solenoid and that didn't work. Something is causing too much pressure in the tank. I'll have to run with the cap loose until I get this resolved.

 

I've been running with the cap loose for about a week and the strange thing is that it hasn't set a code. Any suggestions are welcome.

 

I would say it is the Fuel Tank Vent Valve (V V)

NAPA has them for $14.49 +tax. Part Number BK 7304998 go to NAPA on-line for a picture of it, put the part number in the search, it will come up.

When you replace The (V V) It has a little spring on it and an o-ring, put a little lube on the o-ring before the install. To take the Vent Valve out of the Fuel tank push down on the valve and turn it counterclock wise..The Fuel Tank does not have to come all the way out to replace it, But the Valve is at the other end of the tank away from the Fuel pump. Just be careful not to break other things, like the fuel pump lines or pump. Also Remember SAFETY FIRST. Hope this Helps ? T.J.

 

UPDATE: I finally got around to replacing the fuel tank vent valve and the problem is still there. I have tried only putting about 10 gallons in at a time but if the temperature is above 80 degrees it will push fuel from the vent solenoid above the spare tire after 2 - 3 hours of driving.

Any other suggestions are welcome.

 

I'm having this problem as well after changing the fuel pump and the vent valve. I though maybe I hooked the lines up wrong when I reconnected the fuel pump. Hope we can get some answers in here soon.

 

Saturated charcoal canister? There shouldn't be any fuel getting anywhere remotely close to the vent valve.

The charcoal canister can get saturated from repeated over filling with fuel. Or from a blockage in the vacuum line to the engine.

 

I have this issue with my 99 S10 Blazer.