Re: Car stalls when I take off the gas cap

The condition you described is indicative of a malfunctioning purge valve on the charcoal canister and/or the BVSV valve is closed/plugged. (BPSV is a coolant temperature controlled path for canister vapors to enter the intake manifold.) If you remove the fuel cap to vent all pressure, replace the cap for a few minutes, and then find more pressure upon cap re-removal then you have fuel that is being heated excessively. Ported vacuum is supposed to prevent pressure build up in the fuel tank while driving ... but only if the canister valves and BPSV valve are not clogged or otherwise inoperative. A little puff of pressure is one thing ... a BIG WHOOSH is quite different.

I had my garage check these today & they found both working fine. They put the BVSV valve in a freezer then took it out & found it was opening & closing correctly.

Just now I tried removing the gas cap - and there is no Whoosh - and the car keeps on running!! So maybe there was some kind of temporary heat-related problem that caused the gas smell and the whoosh/stall on Saturday - or - maybe when the garage removed & checked the parts then put them back on that this made a better connection & that fixed it.

I dunno!!!

The BVSV should be closed below about 110 degree F.

- or - maybe when the garage removed &

Forcing air or some carb cleaner thru the ports on the charcoal cannister can remove accumulated goo from the two check valve balls. Ego... fixed venting problem.

Hi Philip,

I just got back from a 1 hour highway run - the gas tank is now on empty - with the car running I removed the gas cap - no whoosh and no stall. So maybe as you say the garage got rid of an obstruction in the charcoal cannister because I had noticed in the past what seemed like a vacuum when I would remove the gas cap after coming off the highway with the tank on empty (sort of the reverse of what I experienced on Sat with gas tank pressure).

Now if I could only get my intermittent starter problem fixed....

Hey... I gotta get it right once in a while. ;-) A small vacuum in evidence when the cap is removed is "normal."