johntorg

I have been having some trouble with fuel cutting out in right hand corners. I have checked all the electical connections I can find but no luck so far. I did notice that when I unscrew the gas cap there is a large hiss of air entering. I was wondering how the tank vents and if this is normal?

jwade944

The tank vents through a pressure relief valve to the carbon tank under the driver front fender. The valve is located above the passenger rear wheel well and can be accessed from inside the car by removing the carpet and a metal cover. The system is pressurized so the hissing is normal.

RedlineMan

Indeed;

Does it suck IN when you take the cap off? I doubt it. It is pressurized, and if you think about it... pressure should help you. The venting system is pretty convoluted and can fail, but I don't think that is your problem. Good creative thought, though. If you're going to check something back there, pull the sender and see if something is blocking the outlet to the tank.

Lemming

Does the amount of gas you have in the tank have an affect? Mine will sputter on hard right handers when I'm low, which I believe is normal.

Weston Dillard

My 89 used to go until it was on vapors without stumbling, but then is started stumbling even at 1/4 tank or more. I discovered that there is a container of sorts inside the fuel tank, that holds the fuel near the pickup under cornering. The top had broken off of that. I re-seated it, but it never worked right. I plopped down $125 for a used fuel tank and it's all back to normal. You don't mention year, though I see the turbo in your avatar. If you have an early car, I don't know if the steel tank has the same sort of setup.

I find that I have to buy a new fuel cap about every 2 years to control the leakage.

West

johntorg

Sorry. Its my 1984 944Cup Car with a steel tank. I really don't know whether the air goes in or out when I open the cap. I'm traveling so I can't test it. The problem seems to occur at any fuel level, although I haven't tested it with a full tank yet. I've got testing days on Jan 17-18 and a race in early Feb. so I have to get it sorted out. It all seemed to start when I changed the head gasket, although that may be just a coincidence. I'll be home Jan 11th and will check out the fuel system and look for any loose wiring.

TedA

Please report what you find out when you get a chance to look at it.

Racerrob

Dont mean to hijack, but what happens if you remove the carbon cannister? Is it dangerous?

RedlineMan

Hey;

I don't think fuel would get out of it, but you would certainly have a lot of fumes coming in the driver's window, unless you routed it somewhere else. I fed it into the intake manifold for a while.

Racerrob

Thanks John

Weston Dillard

On my car, which is a track car, I removed the carbon cannister and all the lines, and replaced the non-vented fuel cap with a vented cap for a 924. I actually used the space where the charcoal cannister was for a cheap Summitt Racing oil catch can. It's all worked well.

West