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Discussion Starter #1
Hi, this is my first post on this forum but i've been reading many threads over the past year and I've realized there are alot of smart individuals here. I am a very active member over at News - NAIOA. I have a 2003 chevy impala ls 3.8.

Anyway, to my problem... I have the cel p0440. I know this has to do with the emission evap stuff and that there is a possible leak somewhere. I realize that this code does not affect performance but I can't pass emissions and I am on my last temp plate. So I am running out of room :icon_cry:

I have already changed the gas cap with a aftermarket one since I noticed the oem cap had cracks along the gasket, I also cleaned up the mating surface. Then my next step that I thought would for sure fix the problem was to buy a tuned pcm from a well known w-body tuner and ask if he would delete that code for me. Well, after installing the pcm.. the tune is fantastic but one problem... still the P0440 code. Very frustrating :pissed:

So with running out of time... I really only see the option to start throwing evap parts at the impy. So I am coming to you guys, where can I start looking to fix this problem.

Thanks for the replys in advance!
 

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If you've already replaced the cap and are sure it is sealing properly the next place I would look would the EVAP purge solenoid. Another reason that code is set is when the PCM senses there is no flow at the purge solenoid. Off the top of my head I am not sure where the EVAP components and solenoids are located on your 03 Impala so you'll have to find that out.

Check to make sure the manifold vacuum line to the purge solenoid is intact and not leaking at any point. Next, I would test the purge solenoid itself.

You can crudely do this buy removing the solenoid from the vehicle and putting your lips to the port that connects to engine vacuum and suck on it. At this point you shouldn't be able to pull any air through it. (it should be closed) Next, use alligator clips to connect one terminal of the solenoid to 12v power and the other to ground. When you do this you should hear an audible "click" and then if you suck on the port again, you should be able to pull air freely through it.

If those tests check out on the purge solenoid, you'll have to move further down the line... throwing parts at it is never an option IMO.
 

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Thank you for the quick response. I am going to be checking this out in a bit.

Is this the purge valve solenoid? I think I remember seeing this sitting on top of front valve cover, but we will see.



Yay.. putting your mouth on car parts is always fun :icon_conf
 

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Yes, that's it. Use some tape over the end if you're worried about it. If you're really dead against it buy yourself a handheld vacuum pump.
 

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Ok cool. So popped the hood shortly after reading your reply and I checked out the purge solenoid. I checked the lines going to it... the line that goes to the throttle body to the valve looks in rough shape in two places. The fuel line looked good, but since it had the line protector over it, i didn't want it cut that but i'm pretty sure that line is just okay.

Don't worry... thats what little brothers are for! I had him just to suck in air on it and he said it wouldn't let him so I did it and he was right. I am not sure how to check it electricaly? If you could could you give me an understanding of what I need to do? I do have jumper cables but the noses of the alligator clips are not needle like to touch the 2 pins.

So tell me if this looks right? Not sure who did this, the car has been in my family since it rolled off the dealer lot in 2003. Is this something that would cause a leak? If so, does anyone know what the part number would be for this line? Hopefully its something I can get off of gmpartsdirect.com



Then we have the plastic fitting that brings the valve line and the fuel pressure regulator line together to the throttle body nipple. There seems to be two cracks. Is this another possible leak?



I am so sick of this emission crap. I don't really want to throw parts at it either, espeically if it ends up being the canister. Since its just stuff I am going to be taking off when I start my build.
 

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OK! I think we might be getting somewhere. First off the solenoid should not allow suction through when it is un-powered, when powered you can pull air freely through it.

Next, that small rubber piece with the splits in it should connect the vacuum port of the fuel pressure regular to the throttle body and also it connects the top port of the purge solenoid to the throttle body, also for vacuum. That piece is a single rubber grommet so-to-speak with two different size holes on the end, one for the small FPR line and another larger hole for the larger EVAP purge line.

With it split like that the car cannot purge fuel vapors and thus, you're probably getting no flow through the purge solenoid which I mentioned above and would set the code for sure. Also, you would have poor engine performance from luck of vacuum input to the FPR in addition to a vacuum leak! All bad things!

Get that piece fixed up. You can use a 3-way plastic "T" with some rubber hose to repair it, or try and source the original rubber grommet but that may be a bit difficult. Fix that and you may solve your problems altogether.
 

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Alright so after searching for 3 way plastic t and figuring out all the custom fabrication (which I am not yet skilled at such things yet) I decided to search for the actual part itself. I was planning on going to a junkyard and seach through multiple cars, just to mabye find one that might be cracked but then i decided to find the part online. I figure out gm does not sell the gromment by itself but actually sells what they call a "harness", which is a pretty creative name if you ask me :icon_roll. Its the the whole recieving line from the purge valve. The part number for anyone with this problem in the future is 24506671, the part can be found on gmpartsdirect for a very good price of $12! I decided that I need the problem fixed now, so I called the stealership and they had one in stock for $30... so i bite the bullet and picked it up.



For sure a huge difference putting it on, it was very hard to slid the grommet over the nipple while the defective "harness" came on and off with no effort. Also the bent tube part by the purge valve is much shorter and makes my defective harness look like it was done with spare tube. Hopefully this is the key to defeating the code.

I reset the pcm, and I am letting it relearn so I will post the results right when i get them! Again, thanks for the help so far! :)
 

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Alright, took the whip through a few driving cycles and used the scan tool to see if the PCM was ready... Well turns out I still have the code :icon_frow

So I suppose it's on to the next step... Where should I be looking now?
 
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