gas cap help????

[1iwilly]

hello to all
i got my 97 awd ls in feb-09 since i've own this van no matter the conditions when i take the gas cap out to put in fuel
i never hear or get air pressure coming out upon releasing=unscrewing the gas cap does any one have the same problem
all my other previus vehicle did it.?? how can i test the gas cap. thanks

['cudapaul]

You should not get or hear any "air pressure" coming from the cap when you unscrew it. It's NOT a problem!
The evaporative control system is always under a slight vacuum to recover any fuel evaporation.
In fact, if the van was driven with the cap missing or loose, or leaking, the computer would set the check engine light.

[Matrixx]

X2 on what cudapaul said 1iwilly, no problems their, your good to go.

[rev_les]

X3........absolutely right. case in point, Friday night, check engine light came on, I read the code, evap emissions, I walked to the fill up door, and sure enough,the cap wasn't on all the way.( I put a locking gas cap on it when fuel was $4.50 a gallon) sometimes it doesn't screw in right the first time, and that time I didn't catch it.The computer periodically tests the integrity of the fuel system to make sure hydrocarbon vapors aren't leaking to the atmosphere.There should be no pressure in the system.

[Got To Go]

This maybe related. My wife's 03 Suzuki grand Vitria recently had a sevice engine light come on one day I took it to my mechanic and he said get rid of the locking gas cap. I did and now the problem is gone. I did n't wait for the Safari van light to come on, I ditched both. I have car alarms on both of them, so stealing fuel isn't a problem. I wasted $$$ on the locking gas caps it seems. Anyone want to buy a locking gas cap, Cheap !!!

['cudapaul]

Check the "O" ring that fits around the gas cap where it mates against the filler neck. They get old and crack. Sometimes you can take the O-ring from the non-locking cap and swap it to the locking one to make it seal better.

Also, always buy a good quality gas cap like Stant or Napa. The others are made in China and frequently, but not always, leak when under vacuum and then you will get the SES or CEL light.

[Matrixx]

Hi Got To Go

I have a locking gas cap, and have had it for about 10 years now. I bought mine at a dealership. The parts person was very specific though on which one to get. He mentioned something about the amount of pressure the cap should hold. Either way, it works fine and no pressure build up with it (the hissing sound you hear when releasing the cap, quite as a mouse).

Buy good name brands for sure as mentioned.