Fuel tank pressure

[Stu_22]

What mantain the fuel tanks pressure and should it be maintaining that pressure even when the car is not on.

I'm halfway through changing to a AFPR but if i scew the fuel cap down petrol starts pissing out so I have to leave the cap undone a bit. The car hasnt run in months though.

Thanks

 

[pimptrizkit]

pissin out where?

from the undone fuel lines??


gravity will help siphone the fuel out of the tank,


the gas caps are supost to hold pressure and suck in on vaccume so the tanks do not collaspe,

i always try to work on my car with little to no gas in the tank, as the air temp changes so does the pressure in the tank, if it rises alot, you can force gas out, then create a siphone

 

[ForcedTorque]

We were having problems with this in Noah89T's car coming home from CHI2K7. He said that it had something to do with removing his charcoal cannister

 

[supra8903]

you have to vent the tank, when the charcole canaster is removed.... you can do this with a vented cap....

search

 

[dbsupra90]

We were having problems with this in Noah89T's car coming home from CHI2K7. He said that it had something to do with removing his charcoal cannister

did you plug the line that went to the canister? if so, like was said you have to run a vented gas cap.

other option is to run the line from the tank to the canister open. extend the vac line that went to canister to the hole in the body under where the canister was mounted.

 

[ForcedTorque]

did you plug the line that went to the canister? if so, like was said you have to run a vented gas cap.

other option is to run the line from the tank to the canister open. extend the vac line that went to canister to the hole in the body under where the canister was mounted.

Noah had the line plugged from the cannister, and had drilled a hole in his cap to vent. It was as if the gas was expanding as soon as we filled up. Could this be caused by the fuel pump warming up on the long drive?

 

[Stu_22]

This is a uk car did we gave charcoal cannisters?

Something must be working to maintain the pressure in the tank the car hasnt run for months but if I srew the cap on tight it builds pressure sure thats not right

 

[mkIIIman089]

you have to vent the tank, when the charcole canaster is removed.... you can do this with a vented cap....

search

No, not if the tube for the charcoal can is plugged.

 

[dbsupra90]

This is a uk car did we gave charcoal cannisters?

Something must be working to maintain the pressure in the tank the car hasnt run for months but if I srew the cap on tight it builds pressure sure thats not right

hmm, not sure on a UK car. do your throttle bodies have 1 or 2 ports on top?

 

[dbsupra90]

Noah had the line plugged from the cannister, and had drilled a hole in his cap to vent. It was as if the gas was expanding as soon as we filled up. Could this be caused by the fuel pump warming up on the long drive?

i wouldnt think so. ive driven mine to new york 3 times (900 miles) and never had a problem. maybe it had to do with the extreme heat? personally id uncap the line and run a vac line down thru the body and see if he still has problems.

 

[mkIIIman089]

^ So you vent raw fuel vapor into the cabin? Sounds like a great idea!

 

[dbsupra90]

not thru the firewall, thru the body. there is a hole w/ a grommet in the lower fender where the fresh air tube goes/went for the canister.

 

[Stu_22]

I dont care about the venting or what to do about the pressure I'm sure this is a featue or design on the supra well the UK lot seem to think so.

The point im not happy with is the car is wasting energy trying to maintain tank pressure when its not runnung surly it should be on ignition live not constant