EVAP leaking??

[Naen]

my check engine light came on and i had a diagnostic check, it says EVAP leaking....I changed my fuel cap to a new one but check light went on again...is this a serious issue?? and does it cost much to have it fixed?

[Porkchop]

Fuel cap is where I would have started too.... the evap is the evaporative emissions system that captures fuel vapors in our car's closed fuel system. If its showing a leak with a CEL, then it is probably leaking somewhere. Maybe trace the return fuel line back to the tank? Check under the back seat and be sure there is no leak? Check the charcoal canister (I think it's under one of the rear fenders...) The fuel system diagram from a Bentley manual would be helpful.

[SoonerBug]

Originally Posted by Porkchop

Fuel cap is where I would have started too.... the evap is the evaporative emissions system that captures fuel vapors in our car's closed fuel system. If its showing a leak with a CEL, then it is probably leaking somewhere. Maybe trace the return fuel line back to the tank? Check under the back seat and be sure there is no leak? Check the charcoal canister (I think it's under one of the rear fenders...) The fuel system diagram from a Bentley manual would be helpful.

That's the right idea. It's got to be in the charcoal cannister and/or lines runnung from it to the fuel tank and wherever else. Or the sensor that tells the computer that you have a vacuum on the system could be bad. A diagram of the system would be very halpful. Having it fixed could be simple or a nightmare. I spent a year with an off and on problen with the EVAP system on my wife's Eclipse. I would replace a questionable hose or fitting and the light would stay off for a month or so. Then on it came again. Never did really find a problem. Good news is it's nothing that will ever effect the way the car runs. Good luck.

SB

[Naen]

i know that it wouldn't effect the car's performance, but the annoying check engine light bothers me...it really does...and it's not cheap to reset the system...sigh

[hannaco]

One of the common problems is with the hoses. They will rot, and pin holes develope causing the problem. At one time one of the site sponsors sold silicone replacement hose sets.
Another common problem is with the valve itself. Just use some cleaner and clean out the valve.

[Naen]

thanx guys...if i point this out to a dealership...will they charge hella expensive???

[jackfrost]

being a vw dealer i would say yes, they would charge you a ton to do it. they charge people 75 and up to change a headlamp bulb and those literally take 2 mins to swap. they are a rip off, do you have a different reputable shop near by? the other thing you may want to invest in a vag com and do the scans yourself, they are well worth the money and you can reset the check engine light yourself.

[Naen]

where do i get the VAG COM ??

[Porkchop]

Originally Posted by Naen

where do i get the VAG COM ??

ww.ross-tech.com

[John Koch]

First things first.....The whole fuel cap very seldom needs to be replaced in it's entirerty.. There is a O-Ring on the under side that can and does dry out and break or become dislodged and won't seal any longer.
In view of the fact that your car has already been scanned and the original complaint was not diagnosed or repaired correctly, should mean another scan at N/C under the dealers service warranty which is usually 12 months/12,000 miles. The service techs can attach either a vacuum or low pressure source to the pressure test port (IM 240) to help find the leak. The dealers service tech. should have done the obviouse repair, cleared the codes and road tested your car for at least 10 miles to make sure that the condition was actually repaired correctly. The scanner is the first line of repair for diagnosis, and the second line of repair for re-checking for repeat codes thrown after the fact just to confirm it was repaired correctly.
Take your car back to the dealer with your invoice and complain that the CEL light is back on and that it came back on right after you left and that you need them to "really" fix the problem this time. Like I said, it should all be covered under the original repair warranty...Good Luck, JK