- This topic has 15 replies, 5 voices, and was last updated 11 years, 3 months ago by
.
-
Topic
-
recently (past 2 days) I’m getting a message to check the gas cap on my lcd display on my 2005 pontiac G6. I’ve checked the cap multiple times. If you turn off the car, remove and replace the gas cap message goes away. car runs fine. a few days before this issue started happening, I’d occasionally notice a smell of gasoline while driving with the AC on outside air, but would only last a moment. I’d pull over and do a smell test around the car and detect no smell of gas. popped hood and can’t smell it there either. I don’t appear to be leaking gas, mileage isn’t affected, so the message and the smell would lead me to the evap system correct?
I can clean and lube the o-ring on the gas cap (just thought about that this morning)
I can replace the gas cap
I can replace the canister vent valve solinoid (if I have to ugh)
I can replace the purge valve hanging off the rear of the intakeI’m not a mechanic, just like to work on my own cars when possible. I’d prefer to not have to lower the tank for the vent valve, so I thought I’d describe my issue and see if anyone has a recomendation. Is it worth taking it to a shop for a smoke test? About how much would that run?
If it is the canister vent valve solinoid, I can get a new one for about $20, but is it something a competent diy can do since the tank has to be lowered? never done that before.
Thanks in advance for your answeres
-
Replies
-
Most likely it’s not a broken part, so best to not start replacing things. More likely some clamp is loose or someone you ran over grabbed onto a hose down there and hung on for dear life, for a few blocks, and that loosened some connection. Happens all the time to me. My dad’s ’69 Mercury Marquis smelled like gas for years, he was too cheap to take it in for servicing and I couldn’t spot anything leaking. It sure stunk up the surrounding air, but it never quite caught on fire. If you don’t have a lift, it might be easier to take it to someplace that does and can do a proper job of dropping what has to be dropped to inspect for leaks.
Try the gas cap first. You may need a new cap. If that
does not solve it.Inspect the evap canister and hoses for
cracks or holes.no check engine light on?Edited title due to new information. Now it’s throwing a code where it wasn’t this morning. It’s a P0455 code for large EVAP leak. I popped the hood real quick and looked at the solenoid on the back of the intake and didn’t see an issue, and inspected what hose I could and didn’t find any obvious cracks, splits, etc.
Edit: There’s a chevy dealership right down the road from where I work so I went and got a new GM gas cap. Still have the check engine light. I’m assuming if that fixed the issue it’ll have to be driven a bit for it to get the code to go away, and it doesn’t have to be manually cleared right? How long do codes take to go away on their own?
You will have to clear the code by using a scan tool or
removing the negative battery cable for 10-15 minutes.I removed the negative battery cable for about an hour while I ate dinner last night, but the MIL came back on today on my way to work.
Do you guys think it’s time for a smoke test, or can you recomend something I can do/check before that. it’ll cost about $85 for the code diagnostic which includes a smoke test if needed. I wonder how bad it’d be to get to the vent valve solenoid or the pressure sensor if i wanted to just try those before taking it in?
You can try to find the leak by making up a batch of very soapy water and use a brush to slop the soapy water over every hose and joint and valve in the evaporative system. maybe you’ll be lucky and see some bubbles. Do this with the engine hot and running so the gas tank system is pressurized.
You probably won’t be able to reach some of the joints where the hoses go into the gas tank or into the canister if the canister is in some hidden area, but it’s worth a try.
I think you have done bout all you can do at this point. The only way to diagnose and repair the EVAP system is buy a knowledgeable person with a smoke machine.
Guessing and throwing parts at it all day might cost you more in the end.
Try clamping the purge solenoid line off.If the solenoid
leaks or is stuck open it will cause excessive pressure back
to the tank.clear the code.see if it comes back.I crawled under the car today and found the vent valve solenoid. I used some crescent double X long nose pliers and a really long screwdriver and got the electrical connector off since the part is above the fuel tank. I metered the solenoid contacts and had infinite resistance. I went into the K-ohms scale on my meter before I called it dead.
For reference, I checked the resistance on the purge valve solenoid and it was at 22 ohms, so that’s probably where the vent valve solenoid should be.
I’m going to get a new AC delco vent valve solenoid and give that a go.
I crawled back under again today and re-did the resistance check on the vent solenoid and it was open. I wanted to make darn sure before I dropped the tank. This time I went a little further and back probed the connector pink wire and saw 12v, but 0v on the white going back to the PCM, so that further confirmed an open circuit on the vent solenoid.
It’ll probably be a weekend or two before I can do this, but I’ll update this thread
I believe Ihave solved the issue. I got an AC Delco vent valve solenoid off of Amazon for $18. I was able to replace it myself without dropping the tank.
Once I had the rear up on jack stands I was able to fit my arm between the frame member and the body and un-hook one hose and the electrical connection. The other hose was out of reach, so I had to use a hack-saw to cut the nipple off the part. then I used some really long needle nose to pull the nipple from the quick connect while I used a set of 90o pliers to squeeze the release tabs.
I also had an issue hooking that same hose back up. I used a set of hose pliers to reach the hose and slide it onto the new part.
Been running fine all week with no more check engine light. Thanks to all you here who helped me diagnose and resolve this issue
You got lucky. Sometimes being lucky is good though. At least you tested the part before you replaced it, well done. Thanks for keeping us up to date. If things change, let us know.
- You must be logged in to reply to this topic.