90 3VZE 2wd auto.

Ok guys, here's what's going on. Now that it's 110+ degrees out my fuel tank has a huge pressure build up. It only does this when it's over 100 degrees or so. It did the same thing last summer as well. When I remove the gas cap the tank releases pressure for well over a minute & not just a little but a lot! I need to figure this out once & for all. Last year a few people suggested checking the vacuum/temp switch thingy on the rear of the intake manifold, I checked it & it was functioning as it should. can anyone tell me where line from the evap canister connects to the fuel tank, is there a simple fitting or is the a pressure type valve? I'm wondering if it may be clogged or just not working?

Please help as I'm affraid the gas tank is going to blow up! I have NEVER seen this much pressure in a tank before.

Thanks, Rich

 

Update, I just went outside & pulled both hoses off the evap canister. The larger one that runs to the tank had fumes & pressure in it, the smaller one that goes to the switch on the rear of the manifold had no pressure at all. Does this mean that the evap canister is clogged or bad? If so where can I find a cheap new one? I don't want to mess with wrecking yard parts if I can help it.

Thanks, Rich

 

If you want a new one, try www.rockauto.com .

 

Thanks for the link. Only problem is that the evap canister is $277.79! A little too pricey for me right now.

 

junkyard?

 

lol, srry i cant help you...but i LOVE your avatar, ahehe hank hill assistant manager, strickland propane

 

lol actually i have a suggestion now...it wont fix the the problem but heres what i would do...just ride around with the gas cap off, or put ice cubes in the gastank.

lol i was just kidding about the ice cubes

 

Yeah, Hank Hill rules!

If I leave the gas cap lose then all of my fuel will evaporate! I'll go from 17 mpg down to 10 mpg lol.

Can the evap canister be bypassed? Just hook the 2 lines together with a barbed fitting?

 

no, youll run into issues

 

lol i think you just helped me out...i my cap is bad, it doesnt screw on it just sits there...i get like 6mpg....and in the morning i have less gas then the night before...i always thought it was a tank leak, and after doing a pressure check i just came to the conclusion my truck had the worst mileage ever...well i guess i need a new gas cap

 

Ok, update. I pulled the 2 vacuum lines off & hooked them together with a barbed fitting. The truck runs fine & no more pressure in the tank, however now it's kinda hard to start due to there being excessive fuel vapor in the intake. I guess I'll be going to pick a part this weekend. It's going to be around 110!

 

What ever happened with this fuel leak? I have the same problem, and already changed my evap canister. It still builds pressure when the temp goes above 90, and eventually starts pouring fuel out the bottom Evap canister hose until I release the pressure on the gas tank by loosening the gas cap.

 

I decided to follow advice as seen here in several posts, and traced the actual hard fuel lines to the tank. using compressed air, I determined that the fuel return from the plenum was connected to the vapor relief line, and the vapor line was connected to the fuel return line. Reversing the lines, and no further trouble, no more gas leaks as the temperature has been hitting mid 90's!

 

had the exact same problem back in december. drove me nuts!!! took everything off the engine and cleaned till my fingers bled. can't explain how stupid i felt when i went underneath and saw the lines were swapped