need a 2nd opinion regarding codes po442 and po440

[ryan347]

This is my first post on this forum, and I want to thank everyone in advance for their help/advice!

So heres the problem: when I fill up the tank the lever on the gas pump pops as if full every 5 or so dollars. It does this on a fairly consistent basis regardless of the pump speed. I have 2 error codes that pop up even after I clear them: PO442 and PO440, and a "check gas cap" warning.

Heres the backstory: The car was sitting in my driveway for a year due to lack of stable work. When I was ready to use it again some work obviously had to be done. I never had a problem filling before, so was skeptical when this issue came up. I took it in and one of the several jobs I paid the mechanic to do was fix the vent valve (it was him who said that part was the issue). Eventually I went to another mechanic because 1 job he lied to me about, and the other he messed up, so I had serious doubts about job #3 and asked mechanic #2 to check out the vent valve a month and a half later. The other 2 jobs are unrelated to the evap/emissions system. I had no problems filling since it was fixed my mechanic #1. Since he checked it out the problem has resurfaced, and of course I took it back to mechanic #2 just be totally blown off. So I took it back to mechanic #1 and they ran a smoke test and said they could not find a leak unless I gave them another 300$ to take off my gas tank. Sigh...

So I really want a 2nd opinion about what the issues/parts may be. Both mechanics are totally untrustworthy at this point. I know mixing mechanics is a bad idea but mech #1 felt like an "upseller" type and I got some bad vibes. This whole thing is focused around the vent valve so Im thinking that is it, but I have no idea to be sure. There are no problems when the car is turned on it is only when filling at the pump. I of course checked the gas cap and looked at the gasket as well, it looks good to me. I also noticed the metal "door" with spring behind the gas cap does not close all the way, but does come very close. I dont think this is the issue because the gas cap should create a seal beyond the door.

I know this is a long post and I thank you all again for taking a look! Also I am having trouble finding a consistently good website to find blueprints and picture schematics, if you know one please post!

[GMCustomerService]

@ryan347, I have read your post about your situation with your vehicle. What is the year, make and model of the vehicle in question?

Michelle, GM Customer Service (assisting Sarah)

[olopezm]

As asked above it will be better to have the model and year of your car so people can give more accurate advise.

So far I would say you might have a problem with either the rubber hoses in the EVAP system or maybe the charcoal canister is damaged. Have you checked the fill neck hoses for any damage? if they are blocked, specially the vent hose, could cause the pump to pop.

Oscar.

[ryan347]

Oh yeah duh, sorry. I figured it would pop up with profile pic.

Its a 2004 Pontiac Grand Prix 110k miles.

This is the best schematic I've been able to find so far: http://www.grandprixforums.net/3-8-s...cap-44195.html

Now when you say the charcoal canister, I assume that's #10 on the diagram? Can you please explain how that would cause the problem? Because the car is turned off when I fill, and it doesnt look like that part plays an effect until its already in the tank...

[olopezm]

Yeah, charcoal canister is number 10 on the diagram. If it is cracked it could cause the p0442 code.

Have you noticed any fuel smell after turning the engine off?

Number 5 in that diagram can cause the pump to pop if it's clogged.

You could easily test the vent valve by removing it and connecting 12v to the terminals, it should click and either prevent/allow air through the valve when energized and do the opposite when not powered. DO NOT try it while it's mounted as fuel vapors could easily explode.

Oscar.

[rkvons]

What's not shown on that diagram is the solenoid on the engine that provides vaccum to the system during tests. Item #2 eventually connects to it. That could be defective, or the wiring to it. Also, the other side of that same solenoid will have a vacuum line to the engine. That could be bad.

[ryan347]

ok... at least I have a sense of direction now. No gas smell at all. I did notice before that the solenoid wiring is taped up and underneath the red and white are seperated, isnt there suppose to be a protective covering?