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Code reader says "very small leak in the evap. emissions system" and local garage says it's gonna be hard to find. They may have to do the smoke thing to find it and it takes quite a while. Read: $$$$. I replaced the gas cap since that's the number 1 thing and it was cheap.
CEL came back on a week later. So, it's a small leak somewhere. REAL small. Anybody have any luck with this one? I'd be curious to know how you found it. Thanks everybody.
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Henry>
One reason why this forum exists is so that members can share their experiences with these cars and help each other. If the answer was to simply go to a dealer for everything, then it would be pointless to pose a question here, don't you think? Yes, there are times when a dealership or an independent is the answer. But, as a mechanic myself, there are times when we are able to avoid going that route and finding the answer ourselves. I would like to think I have done this many times on this site and saved people a lot of time and money. There are many people on this site that are very capable of doing their own work but it never hurts to hear that somebody had the fix for your particular problem. I invite you to share your own knowledge in this way to help others with their questions.
The powertrain control module PCM performs periodic tests looking for EVAP system leaks.
The protocol for a evap leak check mandates between 1/3 to 3/4 of a tank of fuel before it will run the test. Temporarly solution for your car is to keep tank full to the top meaning no test, no MIL on the dash board.
Finding a small leak can be impossible without smoke machine or gas analyzer. The most accurate test method is using an approved EVAP Smoke Machine. It's gonna cost you around 100 bucks to run it. After test you can decide can you fix it by yourself or not.
Test for minor leak:
The purge control valve is closed once a certain vacuum exists, approx. -6 mbar. The system is now likewise closed. Finally the vacuum is evaluated for approx. 30 seconds.
It must not drop any faster than 0.3 to 0.5 mbar per second, depending on the level of fuel in the tank.
Test for micro leak:
The purge valve is closed and a vacuum of approx. -6 mbar is built up again. The vacuum must not drop anu faster than 0.1 to 0.15 mbar. per second for a closed system. If the vacuum builds up more rapidly, the micro leak fault is stored.
Thanks for the input. I'm just going to have the smoke test done and go from there. I'm tired of resetting the CEL ever so often, so I want to find out what's leaking and get it over with. The only thing that's kinda scary is that the shop I usually go to for things like this told me that these very small leaks can be really hard to find, even with the smoke, and that some of them you just cannot find without taking everything apart. Hmmm....scary. So I have to be a bit careful how I proceed, but they are good guys and won't string me along.
Again, thanks for the great explanation. I'll post when they find it.
PO456 CODE......any cures?
