problem with EVAP canister....

[Braxx]

so ive noticed that everytime i go to fill up my gas, when i remove the gas cap there is a "pshhh" sound that comes out of the gas tank like air depressurizing. I have to let it release all the air so that I can fill up my gas tank. Ive seen threads about cleaning out the carbon canister and the LDP. I have seen that you just pull out the canister filter and blow air threw it and maybe some carb cleaner into it. which I will be trying this weekend but my main question is where is the LDP? Ive see people say its under the left rear wheel well and some have said its right next to the carbon canister? and how do I test if the LDP is bad? because this issue is causing me some drivability problems on cold mornings and my gas mileage has been pretty bad. but ive noticed if I release the pressure in my gas tank before I drive in the morning my car starts up easier. I also have already replaced my N80 valve to try and fix this problem. Can you guys please help...this really sucks in the morning!

[STONER]

LDP pump is located left rear wheel housing behind the fender liner. As far as testing scan tool. There should be some pressure release when you remove your gas cap. You could replace your charcoal canister they do become full after a while. Depending on your vehicle some came with an inline filter at the charcoal canister that Audi now just removes and replaces with a hose.

The canister isn't the cheapest though.

[Braxx]

LDP pump is located left rear wheel housing behind the fender liner. As far as testing scan tool. There should be some pressure release when you remove your gas cap. You could replace your charcoal canister they do become full after a while. Depending on your vehicle some came with an inline filter at the charcoal canister that Audi now just removes and replaces with a hose.

The canister isn't the cheapest though.

But I heard that the b6's have the LDP right behind the left rear wheel well. So does that go for the b7's also?

[STONER]

There both in the left rear wheel. remove tire, remove wheel liner and its there.

[ECS Tuning-Audi]

My B5 does this but only when the tank is basically empty, like below when the dash reads "0 miles" If I fill up when the light actually comes on it never happens.

Whats your fuel level when you are filling up and experiencing this?

Jason

[Braxx]

my car has actually run out of gas because of this problem. I ran out of gas because my fuel gauge said i had a quarter tank still but it was just the pressure in the gas tank keeping my fuel gauge from reading properly. Im not sure what i should do.... any help would help because this thing is really messing up my mileage,drivability and my gas gauge reads wrong...


My B5 does this but only when the tank is basically empty, like below when the dash reads "0 miles" If I fill up when the light actually comes on it never happens.

Whats your fuel level when you are filling up and experiencing this?

Jason

[k20actr]

diy here

http://www.audizine.com/forum/showthread.php/455973-DIY-Carbon-Canister-Fix-Pumping-gas-problem?highlight=

[ECS Tuning-Audi]

It might also be that the fuel level sender could be on its way out if that carbon canister DIY doesn't solve your issue.

Jason

[plokm]

it maybe the fuel sender but the fuel sender will not build up pressure like that. Just try the diy first and if that doesn't help try replacing the sender unit

[Braxx]

thanks for the help guys, i just did the canister diy, and it was pretty hard to blow thru the filter...so i cleaned it and i hope that was the problem.... we will find out tomorrow morning when i start up my car! [o_o]

[plokm]

also try pumping your gas to see if it click back every 3 sec or not

[papadelogan]

FWIW I was having the issue of "clicking off" when filling the fuel tank, but I scored an EVAP canister from a B7 that was totaled with just 15k on it for about $40. Hopefully the cleaning sorted you out but if not I'd hit the breakers.

[eyesolution]

sorry to resurrect this thread, but did cleaning the canister work? My car recently started to depressurize air from the gas tank. or was it the LDP?