Bubbling gas tank during boost leak test

[dsmcoder]

When I was doing a boost leak test my gas tank started bubbling at about 20psi and I'm not sure why, anyone have any ideals on what could cause this?

 

[nuclearr]

Are you still running the charcoal caninster if so the check valve might be bad.

 

[PieEyedPiper]

I'm gonna go out on a limb here and wager that that could be quite hard to achieve.

Can you tell us more about it? How you concluded that this was the case?

Air would have to be entering your injectors, through the rail, through the filter and all the way to the pump and out into the tank..

Are you still running the charcoal caninster if so the check valve might be bad.

I hadn't considered this. Could you describe how the charcoal canister could let air from a boost leak test into the gas tank?

 

[dsmcoder]

I'm gonna go out on a limb here and wager that that could be quite hard to achieve.

Can you tell us more about it? How you concluded that this was the case?

Air would have to be entering your injectors, through the rail, through the filter and all the way to the pump and out into the tank..



I hadn't considered this. Could you describe how the charcoal canister could let air from a boost leak test into the gas tank?

Well when I hit 20psi I can go to the back of my car and clearly hear the gas tank bubbling. Does this mean my injectors are bad?

Are you still running the charcoal caninster if so the check valve might be bad.

Where is this charcoal canister located?

 

[Black-Out]

definitely sounds like the charcoal canister vent valve is mechanically stuck open,as mentioned by a couple others...pinch off the line and re-test to see if this stops the perculation...the charcoal canister should be located on the right fender just in front of the transmission.

William-

 

[red1993gsallmt]

Maybe the fuel pressure regulator

 

[bradikus7]

If this truely is the case than I would look into the FPR. Since you do have a vacuum line from the IM to the FPR, if it were to leak passed into the return would be the only way I could think of to get to the gas tank.

 

[dsmcoder]

definitely sounds like the charcoal canister vent valve is mechanically stuck open,as mentioned by a couple others...pinch off the line and re-test to see if this stops the perculation...the charcoal canister should be located on the right fender just in front of the transmission.

William-

I no longer have the canister hooked to my vacuum lines that I know of so it shouldn't be the canister but I can check again to make sure it's not connected.

If this truely is the case than I would look into the FPR. Since you do have a vacuum line from the IM to the FPR, if it were to leak passed into the return would be the only way I could think of to get to the gas tank.

I thought it could be this to so I disconnected the vacuum line from the fpr and it did not help.

 

[eligst21]

Try taking off the return line of the fpr. It could be that the valve inside is not shutting and is allowing the air to travel back to the tank. Seems funny, but maybe try it. Or try a fuel filter or something like that.