Fuel Tank Pressure????
Thread Starter
6th Gear
Joined: Jun 2011
Posts: 6
Likes: 0
Fuel Tank Pressure????
I have a recently acquired 1985 & when I take off the fuel cap, there is a significant amount of pressure. It will vent for a good 15-20 seconds with a lot of pressure? Is this normal? I have tried replacing the fuel cap, but no change. Any ideas welcome.
Thanks.
Thanks.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The tank is vented through the charcoal cannister. There is a pressure relief valve between the two. A little pressure buildup is normal. The recirculating fuel system makes the fuel hotter and hotter as you drive, so pressure builds up. Mine usually is just a "pffft" and it's done, but I have seen it take 15-20 seconds, but that's VERY rare.
There is also a backup pressure relief valve in the gas cap. It's set pretty high because it's an emergency thing only. Don't want to pollute the atmosphere with those nasty hydrocarbons, ya know?
There is also a backup pressure relief valve in the gas cap. It's set pretty high because it's an emergency thing only. Don't want to pollute the atmosphere with those nasty hydrocarbons, ya know?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Disconnect the rubber line from the steel vent line on drv front wheel well ( rubber line runs to canister under drv side headlight ) and try to blow back to tank
