I have a '01 TJ w/ a 4.0 I6 that is displaying engine code P0442 - evap leak (small). I can smell gas every time I start the engine. I have checked all the vacuum lines and evap system (but can't find anything really glaring). I have hose clamped everything for starters but don't know a good way to check for vacuum leaks.

I have replaced the gas cap...I need some help on looking for other possible causes. I don't see any of the injectors leaking either but that doesn't mean they aren't.

Has anyone else had this problem, I would like to solve it myself but if I have to I'll bend over and take it to the dealer. Any info would be great.

check the vent tubes comming from the gas tank. since this is the entire point of the evap system, burning fumes from the gas tank, then you may try that. there should be two on top of the tank. I cant really see how the computer would know if there was a leak unless there is some sort of sensor in the evap purge canistor or somthing, or maybe there is some descrepency between the map sensor and some other sensor. have you noticed a performance loss? I've always wondered if the evap system would hurt system performance if disconnected.

I have noticed a very rocky idle from time to time due to this engine code...if I get too fed up with it I just reset the computer and my idle stays rock solid until the light goes off again...I seem to lose a little power throughout the powerband as well.

Could have a faulty purge valve im not familiar with them all but on the fords they have a sensor in them, and there is a series of tests ford has you go thru to test it mainly checking resistance between pins etc. The purge valves on a ford taurus was like 40 bucks or so if they are similar in a TJ I don't know. But if that is faulty will trip code's and can cause like you experience rough idle's etc.

Good luck finding it. My wife's 01 has the same problem (without the gas smell). Check engine light comes on and code is evap leak. Happened 10 times since Thanksgiving. Dealer has replaced the gas cap, sensor, vacume harness, purge solenoid (twice), Charcole cannister, sensor, and reprogrammed the computer (that worked best... no light for 3 weeks). Light is on again and the service manager was "looking into it and would call me back", that was 3 weeks ago and still haven't brought it in. I think I'll talk to the guys at Chrysler Electronics here in town and see if there is a way to bypass the evap sensor (I'd like to keep the check engine light for other systems and this problem doesn't affect the operation of the jeep.

Robert

Thanks for all the info, I think I'll start by trying to replace the purge valve and go from there. Unfortunately it sounds like it may be a no win situation and I might just have to live with it until I have enough extra money to take it to the dealer...and even then by the sounds of it - may not fix the problem...

If I have any success I'll post again, if anyone else has any success I would greatly appreciate it if they post as well.

Might be worth it to invest in a Mity-Vac kit with a gauge. You'll probably need it for troubleshooting anyhow. Great for bleeding brakes too.

Goddamn newfangled OBD II crap.

HTH,
Jake :)