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-   -   Evap Lines O-Rings? (https://www.gmforum.com/gmc-chevrolet-truck-suv-177/evap-lines-o-rings-314406/)

TommyB 09-06-2022 09:39 PM

Evap Lines O-Rings?
 
Hi everybody, I recently bought a 2002 Chevy Trailblazer LTZ. 4.2 straight 6 cylinder. 177,000 miles.
Anyway, I passed the safety inspection but failed emissions with a code set of P0440, Large Evap leak. I visually checked everything I could get to and didn't notice anything right off the bat. I replace the vent and purge valves. also replaced the gas cap because it had a bad O-ring seal. still set code.
I took all the connectors off and cleaned etc, but the O-rings in the evap lines looked kinda flat, and when pushing them back on they felt kinda loose.
I'm going to do a smoke test tonight or tomorrow.
My question is, can I replace just the O-rings in the evap lines? I'm not sure I can find new lines, though I haven't looked to hard yet.
I'll let you know how the smoke test goes. thanks!

CathedralCub 09-06-2022 10:52 PM

You can get just the O-rings, but the smoke test will tell you where to look before you go through all of that.

TommyB 09-06-2022 11:08 PM

thanks, going out to do it in an little while.

TommyB 09-07-2022 03:29 AM

went out to do the smoke test and noticed the schrader valve was loose on the test port. I hadn't checked it before because I thought it was a fuel line. Duh. Anyway, when I tried to tighten it it just spun. So I put the hose for the smoke thing right over the threads where the cap goes on, it fit nice and snug. I put smoke into the system and looked around and didn't see any coming out anywhere.
BUT... I forgot to ground the vent valve to close it. another DUH! Would that screw up my test? If so I can do another one tomorrow, it was pretty easy.
And I also got the pressure up to about 10 psi. Would that damage anything? I used a bicycle pump.
opinions please. and many thanks.

carfixer007 09-07-2022 03:00 PM

You should have a flow meter that lets you know it's charging the system with smoke. I'm not sure it took any. What kind of machine?

TommyB 09-07-2022 03:24 PM

the fact that I used a bicycle pump should give it away :smile:. I made it from a video on YouTube. It blows out plenty of smoke.
what about the vent valve?

carfixer007 09-07-2022 04:44 PM

Good luck with that.

TommyB 09-07-2022 09:07 PM

not everybody can afford a $100+ smoke machine. if I had money I'd take it to a dealer. what the hell do you think this forum is for!
Does anyone else care to help me???

CathedralCub 09-08-2022 12:27 AM

The valve that spins loosely probably leaks.

I wouldn't put 10PSI to any part of the fuel and system unless it is by using the fuel pump connected properly.

TommyB 09-08-2022 03:47 AM

thanks CathedralCub but I'm working on an evap leak. Did you mean evap and not fuel? I'm gonna try and find a new valve ASAP. But right now I have no idea where to get one. I have a bunch of schrader valves for AC but they are all different sizes. I'll let you all know what I find.


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