need help bad
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
Actually, alaskaman - the gas cap is vented (as I expected it should be)...otherwise the gas tank would collapse as the fuel is being used. It's a one-way valve to let air in.
To the OP...you indicated that the fuel filter and fuel pump are new...how new? Has this problem started since either was changed? If so, there could be a number of things that happened that would cause the problem. Do you smell gas? Any leaks? Lines connected properly, 0-rings in place....
To the OP...you indicated that the fuel filter and fuel pump are new...how new? Has this problem started since either was changed? If so, there could be a number of things that happened that would cause the problem. Do you smell gas? Any leaks? Lines connected properly, 0-rings in place....
Pro
Joined: Nov 2005
Posts: 602
Likes: 0
From: North Bay Ontario
The gas cap is vented....I refer you to http://forums.corvetteforum.com/c4-t...terectomy.html
...or simply take the cap off, turn it over and you'll see a spring loaded valve that lets air in - of course, the cap does not vent fuel vapours to the outside - that is why we have the charcoal cannister and evap system that purges the vapours into the intake system.
...or simply take the cap off, turn it over and you'll see a spring loaded valve that lets air in - of course, the cap does not vent fuel vapours to the outside - that is why we have the charcoal cannister and evap system that purges the vapours into the intake system.
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
Thread Starter
Intermediate
Joined: Jan 2012
Posts: 35
Likes: 0
u know what leesvet u might be wright cause i do remember when i install the new fuel pump i did noyice that the little filter screen or whatever its called was hitting the bottom of the tank and i had to put a little pressure down to screw the pump to the tank ill check on that tomorrow and post it here thanks a lot u guys for the info u guys are great thanks again
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Corvettes have a circulating fuel system. The pump pushes more fuel than the engine can use up to the fuel rail. The fuel pressure regulator bypasses the extra fuel back to the tank through the return line. One side effect of this system is that the fuel picks up heat at the fuel rail and gets hotter and hotter as the engine runs, which builds pressure in the tank. You won't see the pressure in the tank when the engine is cold, but it will happen if you remove the gas cap after driving for a while.
The gas cap has two valves in it. One lets in air. The other is an emergency pressure relief and doesn't normally operate. The fumes and pressure in the tank are extracted by the charcoal cannister system. One failure point of the charcoal cannister system is a little rubber hose that joins the metal line from the tank to the metal line to the charcoal cannister. It is under the car in front of the driver's side rear tire, and looks like this:
The gas cap has two valves in it. One lets in air. The other is an emergency pressure relief and doesn't normally operate. The fumes and pressure in the tank are extracted by the charcoal cannister system. One failure point of the charcoal cannister system is a little rubber hose that joins the metal line from the tank to the metal line to the charcoal cannister. It is under the car in front of the driver's side rear tire, and looks like this:
Thread Starter
Intermediate
Joined: Jan 2012
Posts: 35
Likes: 0
Hey cliff do u have a diagram or a picture of how the hoses should be conected at the canister mine were all disconected when i got the car and i connected them but I don't know if they are correct or not
Team Owner
Joined: Jan 2003
Posts: 20,293
Likes: 240
From: Summerland B.C. Canada
In my mind, if there is the sound of air moving in or out, when cap is removed, something is not right. The tank is vented to canister and the canister can vent to atmosphere.
Check to see if the vent line from tank to canister is plugged or not hooked up properly.
From my 86 FSM
http://members.shaw.ca/corvette86/Ev...l%20System.pdf
Check to see if the vent line from tank to canister is plugged or not hooked up properly.
From my 86 FSM
http://members.shaw.ca/corvette86/Ev...l%20System.pdf
Pro
Joined: Nov 2005
Posts: 602
Likes: 0
From: North Bay Ontario
jj - you really need to re-trace all of the work that you've done recently. There has to be an improper line or connection related to the fuel supply that is causing air to get into the fuel rail. You've mentioned that you've done several things recently with the fuel system - I would be starting there. I don't think it's your gas cap.
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