Major Fuel Leak from Charcoal Canister

[LagunaSecaBlue]

I recently replaced my fuel tank and lines. I drove the car fine yesterday to get my muffler put on, went to emissions failed because my fuel cap doesnt seal, and my purge line from the charcoal canister was disconnected. Go back to emissions today with the purge line hooked up to the intake manifold as well as a new gas cap and when I get there gallons of fuel start to shoot out of the bottom of the charcoal canister and wouldnt stop till I pulled the gas cap(had to use pilers to get it off) and when I did the gas filler made a very distinct depressurization noise.
What is causing this?

[bmwman91]

It sounds like you somehow got the fuel return line connected to the evap purge line. If things are hooked up properly, I cannot see any way for liquid gas to get into the evap system.

When you look at the fuel hard lines under the car, there are 3 important ones. The fuel feed hardline is easy to spot since it connects to the outlet of the fuel filter. You obviously have the feed side connected properly since the car runs.

Right next to the feed line is the return line. It is the one that connects to a hose back by the filter, and that hose is pretty long: it runs form the hard line all the way to the return pipe on the fuel pump bracket/cover.

Then there is the 3rd hard line under the car, which is more in-board. That's the evap system line, and it is supposed to connect to the evap expansion tank that lives above the rear passenger side wheelwell.

It sounds to me like you have the return and evap lines crossed. All of the return fuel is being forced through the evap system which will eventually make its way back to the tank, and then you are sucking almost full vacuum on the fuel return line (at idle and when engine braking) which is definitely going to be bad for the fuel system components.

You need to check and correct this, ASAP! It is dangerous for sure. Vacuum hoses are not rated for fuel immersion as far as I am aware. You are running a serious risk of burning your car to the ground. I'm not trying to give you a hard time, it's just concerned advice.

[LagunaSecaBlue]

It sounds like you somehow got the fuel return line connected to the evap purge line. If things are hooked up properly, I cannot see any way for liquid gas to get into the evap system.

When you look at the fuel hard lines under the car, there are 3 important ones. The fuel feed hardline is easy to spot since it connects to the outlet of the fuel filter. You obviously have the feed side connected properly since the car runs.

Right next to the feed line is the return line. It is the one that connects to a hose back by the filter, and that hose is pretty long: it runs form the hard line all the way to the return pipe on the fuel pump bracket/cover.

Then there is the 3rd hard line under the car, which is more in-board. That's the evap system line, and it is supposed to connect to the evap expansion tank that lives above the rear passenger side wheelwell.

It sounds to me like you have the return and evap lines crossed. All of the return fuel is being forced through the evap system which will eventually make its way back to the tank, and then you are sucking almost full vacuum on the fuel return line (at idle and when engine braking) which is definitely going to be bad for the fuel system components.

You need to check and correct this, ASAP! It is dangerous for sure. Vacuum hoses are not rated for fuel immersion as far as I am aware. You are running a serious risk of burning your car to the ground. I'm not trying to give you a hard time, it's just concerned advice.

Exactly the problem. It has been fixed. The purge line must have started the vacuum and started sucking since it wasn't doing it yesterday.