when my tank gets low i get gas of course. well when i open my gas cap it sounds like i just opened an air valve. the lower i am on fuel the more air comes out. is this normal? i would think that the gas tank vent would prevent air pressure from building up in the tank.

 

The EVAP system should prevent this. What are we talking about, a 72 Pinto? Please let us know what year/version/engine...

 

sorry blake, youve been so much help! its my 91 accord ex 230k. that has been giving me problems starting and ive tried nearly everything. im sure its something simple. im getting fuel pressure and spark but the intial start up is rough and after about 8 hours of sitting it cranks forever before starting.

 

Yeah, I see so many different threads I can't remember who owns what cars.

1991 is old enough, it's not OBD-2 so the ECU has no way of knowing if the EVAP system is plugged up or not working. It could be completely blocked & the ECU won't throw a CEL.

The tank is SUPPOSED to be vented through the EVAP canister, which might be located in the engine compartment. Not real sure where...