Please Help - Bad Idle - Evap Purge Valve Problem (P0440) [Archive] - GrandAmGT.com Forum

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intence
01-13-2005, 10:39 PM
Today my car threw an SES, had it checked out and it was P0440, so something with the EVAP system. I changed wires last week, so thought i'd see if something came out etc.

Checked the gas cap, it was on pretty tight. I looked under the hood and noticed that the hose from the PCV valve that runs to the Evap Canister Purge Valve had come out (just to be sure, the hose goes from the PCV to the top connector on the Purge valve right?).

I plugged it back in, but as soon as I started the car, it wouldn't idle smoothly, the idle would jump up and down continuosly. Unplugged the hose from the Purge Valve and the car runs fine again, plugged it back, and the crazy idle came back.

I don't want to leave the hose out, since i'm going to keep throwing the P0440 code (and will prolly fail my emissions test in a few months).

The car ran fine for a few days, and i'm pretty sure the hose was plugged in, any ideas on what the problem is, the purge valve? Is there anything else that could be causing it?

Anyway, as always, i'd really appreciate any advice/ideas.

AleroME
01-13-2005, 10:51 PM
clean the Air idle control valve in the throtty body. Mine used to surge up and down when i first start up.. after i cleaned it.. idle is smooth.

Malaclypse
01-13-2005, 10:57 PM
Try tapping on the evap purge solenoid with a screwdriver handle when the line is plugged in to see if that clears anything up.

Another question. did you buy the car used or any time recently?

intence
01-13-2005, 11:16 PM
Nope, the car was bought new. Relatively few problems until the LIM was done, then it seems like it's been one thing after another, but relatively minor. Do you suspect something is seriously wrong with it?

Will hitting the solenoid possibly force it to "work", so if everything's fine while hitting it, I should replace it? I'm sure I wouldn't have missed plugging the line in when I chnaged the wires, and the car was fine all week until today, then the code got thrown. I thought it was just the line that came out, but i'm not sure why it would affect the idle when plugged in.

Thanks Richie, i'll also check out the throttle body, but the strange thing is, with the vaccum line unplugged, it runs fine, could the throttle body still be a culprit?

twisted
01-14-2005, 07:17 AM
i would just be safe and replace the part if you have to hit somthing to get it to work the is usualy somthing wrong .

mwolverines
01-14-2005, 08:00 AM
mine was also the air idle control valve. it was off a bit, fixed it and worked fine. it did however act up again in a few days so i replaced it. works great, try it.

intence
01-14-2005, 08:55 AM
Thanks for all the suggestions. Could it be the idle air control valve if the car idles perfectly when the hose isn't plugged into the EVAP canister purge valve? The runs fine when that hose is out (the one from the PCV). As soon as I plug the hose back in though, the erratic idling starts. It's not erratic really, it seems pretty controlled, going up then down.

I'm going to try hitting the solenoid, and if it helps, i'm going to change it out. It sounds almost as if the solenoid opens and closes teh valve over and over (same as putting my finger over the hose, then opening it, over and over). Does is still sound like the idle air control valve could be the culprit?

coupe
01-14-2005, 09:08 AM
how much for the aicv? and where to get it? How you clean the one you have?

intence
01-14-2005, 09:44 AM
I believe the aicv lists for around $100, you can probably get it on gmpartsdirect.com though.

Wouldn't the AICV control idle at all times? My idle's fine when the hose from the PCV to the evap canister purge valve is out. As soon as I put it in, the idle jumps and then drops ... pluses would be a better word. It's not a rough idle (i've had that before), but this is very controlled jumps up then drops down.

Is the evap canister purge valve supposed to stay open for a while? It sounds almost as if it's opening and closing (causing the up/down idle).

intence
01-17-2005, 11:16 AM
Changed out the Evap Canister Purge valve, and the car is idling perfectly :) Put over 100 miles on it so far with no SES light ... keeping fingers crossed.

coupe
01-17-2005, 09:50 PM
I dont get an SES light. The RPM's just jump up and down when i start her up, ussually its after i just drove it.

intence
01-17-2005, 10:58 PM
I'd try the aicv, when last have you changed your plugs, wires, air filter etc?

Pontiac Ninja
01-18-2005, 07:27 AM
hey I don't have to start a new thread people are already talking about it. My car just started doing this idle surge up and down a few days ago, right after I did my MAF PCM re-learn by unhooking the battery. COuld that have anything to do with it. It only pulses (surges) up and down like once a day or every couple days. The lights go up and down with it also (as I read some other peoples doing in another thread). Should I try this AICV or the canister purge valve or could it have to do with unhooking my battery a couple times for the hour (I had to do it twice for the MAF PCM re-learn). Thanks. Hopefully someone can answer mine also!! Oh, and NO SES lights for me either!!

intence
01-18-2005, 08:59 AM
I dunno if it helps, but whenever I pull the negative connection to the battery, and the fuse (for PCM relearn). I let the car idle for a while. How much have you driven since the relearn ... it takes a while for it to learn everything.

I threw a code when the tube to my Evap control valve was out, it's when I plugged it back in that I had the bad idle, but I suspect the Evap valve wasn't working, so the air couldn't escape.

rckrzy1
01-18-2005, 09:00 AM
OK you say the pcv was not hooked up for some time ? If so there there may have been no vacuum to purge your evap canister which may be full of fuel, if so it should empty it out with a good high way run . I'd try that.

Pontiac Ninja
01-18-2005, 10:38 AM
I dunno if it helps, but whenever I pull the negative connection to the battery, and the fuse (for PCM relearn). I let the car idle for a while. How much have you driven since the relearn ... it takes a while for it to learn everything.

I threw a code when the tube to my Evap control valve was out, it's when I plugged it back in that I had the bad idle, but I suspect the Evap valve wasn't working, so the air couldn't escape.


Its been driven about 100 miles since the re-learn, not too far I guess. I did take it out on the highway and such for about 30 minutes after I did the re-learn though. I didn't pull the fuse when I did the re-learn. Which fuse are you talking about?

intence
01-18-2005, 10:53 AM
I always thought you had to pull the fuse labelled "PCM Batt" but maybe i'm wrong. The fuse location is under the hood, but the exact position varies from year to year, so you'll need ot check the listing under the fusebox cover.

Pontiac Ninja
01-18-2005, 02:22 PM
I always thought you had to pull the fuse labelled "PCM Batt" but maybe i'm wrong. The fuse location is under the hood, but the exact position varies from year to year, so you'll need ot check the listing under the fusebox cover.


Sounds reasonable, I just never heard from anyone that you needed to that. Somone else on here said to remove the neg. batt terminal for an hour or so, but have the lights turned to the "on" postiion at the same time to drain any extra juice from the pcm. thanks

DarkKnight
01-19-2005, 04:12 PM
There is so much misinformation in this thread. :rolleyes: The Evap tube is a vaccum line. Since it's been disconnected the PCM probably compensated for it by choking off the IAC (proper term - Intake Air Control) motor, and enrichening the mixture (since the evap system provides a small amount of fuel vapor). When you connect the vaccum line back on the engine doesn't have enough air at idle (assuming the canister valve is held closed), or the mixture is too rich (when the valve is opened). You don't need to hit anything with a screwdriver unless the evap purge valve is frozen open or closed from the cold. Just reconnect the hose, do an idle relearn procedure and try driving the car for a while. If it doesn't work itself out after a tank of gas, then you might have amore serious problem elsewhere. However, if the IAC was broken you would have no control what-so-ever with your idle and it wouldn't be surging (which is the IAC trying to correct the idle), it should simply stall or rev high. IACs are also very common parts. They are the same on all SFI and MPFI 660's. You shouldn't have to pay more than $10 for a good lightly used one. Heck I probably have 3 or 4 just sitting around my driveway. ;)

coupe
01-19-2005, 06:44 PM
Im so confused.
What exaclty should i do to fix this surging idle and the stalling out that happens sometimes. Just replace the the IAC?
What exactly is the idle relearn procedure? How do i do it?

Pontiac Ninja
01-22-2005, 11:33 AM
I figured out my problem with the surging in the idling. Its because of my Pro-M MAF!!! It has made my fuel/air mixture too rich and the O2 sensor trys to compensate and it spikes up and down. Every few key turns its trying to compensate again and it will make the idling surge. I have contacted Pro-M and hopefully they have some idea for me, because I don't want to get rid of my MAF!!!But then again I don't want a clogged cat either!