i just got the cel 31 last week and had the code cleared twice. well needless to say, it came back. i went to order a new gas cap today but it won't be here til wednesday. besides that, i was checking around the passenger side today, under the powersteering canister, i noticed a lot of dirt down there, but not moist. could that also be where the "EVAP system leak (small)" is coming from? who ever solved the CEL 31 problem, please help me out. thanks to anyone who responds.

I have replaced my EVAP/Purge solenoid and a shit load of wires. I've heard once that it could be the roll-over valve on the gas tank. However, this requires dropping the tank and I'm not willing to do that. CEL31 is my codriver of 3+ years now.

yea i ve read your posts, and i am on the same boat as your are. one questioon tho, have you ever replaced your gas cap? when i had my car diagnosed, it said "EVAP system leak (small)" so i was told to change the gas cap. just ordered it today for $12 from satan. i ve searched on google that the 31 can mean numerous things and if you use a scantool or something, it will tell you exactly whats wrong. it can even show a pinched vac line, supposedly or a faulty purge solenoid. the link on the pcm codes from the main page was just too vague. you have to get it scanned.

i also read to drive over bumpy roads to get rid of the cel but i think that directly relates to the rollover valve. i was thinking that the bumps would probably knock the valve with a positive effect thus turning off the cel for a bit. if it was a leak, i don't think all the bumps in the world would affect the cel light. just a thought tho. i drive in NYC all the time, the roads are worse than gravel roads and my cel has not once turned off.

as of now, i just have to cross my fingers with the gas cap. any other help would be greatly appreciated.

does anyone with the cel 31 know exactly what it means? i have the cel 31 which says "evap system leak (small)". anyone else have that cel 31?

__________________________________________
~Chris
03 SRT-4

When the 31 first showed itself, I was told to get a new gas cap too. I just bought one at AutoZone for about $5 I think. Didn't fix it. I have tried to get them to run the scan tool on my car and they couldn't hook it up. Said they didn't have the right equipment for my "unique" vehicle. Furthermore, I actually blew $192 at Steven Mitsubishi in Wichita, KS trying to get this thing diagnosed. After a day and a half, they still couldn't get their scanner to communicate with my ECU (idiots). They ended up telling me it was the EVAP/Purge soloenoid, which I replaced for $10 from the Salvage yard (better then the $197 they wanted + labor + tax). Still no fix. I will tell you this - CEL31 won't just go off when the car's on. If shaking something loose can reset it, you won't know until you retstart the car. I have had this code running several times when I hook up the PocketLOGGER and it shows the same thing: EVAP system leak (small). That could be due to Mike using the DSM VFAQs when he wrote the software, I dunno.

I say you just live with it. It has little effect, if any, on performance. You should just run a keydance a couple times a month to check for other codes and be sure that, if it ever goes away, that you make sure the bulb isn't dead. Trace your vac lines first, then look to replacing EVAP components up front, then it might be the roll over.

Good luck to you sir. Figure this out for me. I think it's one of the more common codes and yet, one of the most difficult. Here's some more food for thought: I currently get 31-25-31-22. Yet, when one goes away, they all go away. Maybe there's some sort of relation to the intake mani? Idle speed (25) can be affected by vac lines on the mani as can the IAC. Coolant temp signal voltage low (22) can affect performance as the ECU needs to know temperature to adjust the A/F mix too.

Won't go away for me either. I reset using my scantool and it comes back after a few months. I have not been able to find a solution for this problem.

-Chris b.

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Built. That's All...
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www.monkeybuttpirate.com
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2 Fingers of Scotch with a milk back... Stat!

anyone else? i really hate that light but i need it functional so ripping it out is out of the question. i m sure most of you know what i mean.

All i can suggest is you invest in a datalogger/ pocket logger. That will allow you to check the codes and the functionality of all that is going on in the ECU. Also it will allow you to reset the codes. This has been the only way I can get the CEL 31 to go away. Every other parameter in my datalogger is correct and in spec so I think the CEL is not too functional.

-Chris b.

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Built. That's All...
.........................................................................................................................
www.monkeybuttpirate.com
.........................................................................................................................
2 Fingers of Scotch with a milk back... Stat!

as for checking the codes, i m good with that, my shop does it for me, free. they cleared it for me too but it came back the next morning while warming up. also, for those with cel 31, does you car rev by itself at times? like at a stop light or even warming up in park, neutral?

my car "hunts" for idle. Sometimes she idles about 800 (like she used to before the rebuild), but other times she'll idle up around 1200. Then sometimes she'll kinda undulate up and down by a couple hundred rpm. No biggie. I didn't get machine-shop tolerances when I ported my tb and runners, and my IAC may be acting up (CEL 25).

One thing I can tell you that I'm pretty sure about this code, is that whatever leak causes it, it is not a constant leak imo. You can reset it and go a month before it comes back, and other times it comes back the next time you start the car. I've put over $500 into solving this enigma, how much are you going to blow before you decide to just do a keydance from time to time like the rest of us? Don't sweat this too hard man. Short of replacing the entire EVAP system, I doubt it will go away. And chances are, if you manage to score a 2GNT/ASOG from a salvage yard, it died with the CEL 31 too and then you'd really be pissed.

LOL. Just check you check codes from time to time man. You'll be okay.

^^^ Agreed.

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Built. That's All...
.........................................................................................................................
www.monkeybuttpirate.com
.........................................................................................................................
2 Fingers of Scotch with a milk back... Stat!

thanks for the insight. this shit sucks. it seems like these cars are built to be fixed. the reason i wanna keep this car running in tip top shape is because i need a ride till i buy a supra. i m trying to not buy another car unless its an mkIV supra. i love supras but can't afford one now. seems like those things never have problems.

just in case tho, does anyone know the total price for an entire evap system? this is just to prepare myself for the worse case scenario. thanks guys.

If your EVAP system totally dies on you, you will simply vent gas fumes from the gas tank into the atmosphere directly, instead of filtering them through the charcoal cannister or whatever. And even then, it's a minimal thing. If you parked in a tin shed on a summer afternoon and kept the door closed, you might be sure to put out your cigarette before entering, but otherwise, it's really nothing.

Trust us. Just get used to your new co-driver, man!

I was also hoping there was an easy fix for this problem. Cuz the main thing here is that I'm in SoCal and just having a CEL is an automatic fail. Even resetting it won't make u pass as their has to be some stored data in the ECU for ur car to pass emissions. I don't wanna spend 250-300 just to pass smog when the only problem is a code 31. Hell, if I were turbo, I'd pay that much for smog. But I'm only NA with minor bolt-ons...

SonicYan aka Mikey
1997 Eclipse RS
Pinoy Reppin' SoCal 2GNT
Best: 16.35 @ 83.05 MPH

well, the new gas cap was a waste of money. besides getting used to the cel, has anyone heard of the cel 31 ever being fixed? i don't want to get used to it... i just got the car this past summer and fixed it up. after all the time and money invested into it, i do not want to see a stupid cel. worse comes to worse, i ll bring it to satan but does anyone know if they can fix it?

Theoreticaly, if you changed out your vac lines and made sure all the solenoids were working right (test proceedure is in the Chiltons), the only thing really left to test out would be the rollover valve. It's the one piece of equipment mounted on top of the gas tank that you can't get to by pulling the back seat.

Way back when I was after this CEL hardcore, I had a shop pressurize the system with some sort of smoke to find the leak. They said smoke was coming out from under the rear pass. side wheel well. Right next to where the roll over valve is. Someone posted here once upon a time that they had seen several DSMs with this valve conk out on them and thought there should be a recall on that valve, but it's not a safety issue to Mitsu, so don't expect them to be doing anything about it any time soon.

how much does the solenoids cost? as for the vac lines, i can use regular tubes right? do you know how much it is to change out everything besides the rollover? i heard the rollover was about $300 because of the labor. thanks

Well I know for a fact, at least for the turbo guys, that this CEL is caused by a valve right between the gas tank, and the spare tire well, under the car. There is a rubber diaphram inside it, and can tear if it sees boost pressure. In the center of this diaphram, is a plastic pole piece, with sharp edges on it, on the underside of it, and if boost pressure gets in it, can tear the diaphram on those edges. Someone on here figrured it out, and then I took mine out, took it apart, and that was it. You can file down those edges on a new valve, and put it back together, and its fixed. This valve will have like 3 vac lines coming to it. You cant miss it really. Its a bitch to get off though...

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Originally posted by SonicYan
I was also hoping there was an easy fix for this problem. Cuz the main thing here is that I'm in SoCal and just having a CEL is an automatic fail. Even resetting it won't make u pass as their has to be some stored data in the ECU for ur car to pass emissions. I don't wanna spend 250-300 just to pass smog when the only problem is a code 31. Hell, if I were turbo, I'd pay that much for smog. But I'm only NA with minor bolt-ons...

________________________________________

2004 WRX - WR Blue Pearl
1997 Eclipse GS - Royal Sapphire Pearl

Originally posted by eclipse804

Originally posted by SonicYan I was also hoping there was an easy fix for this problem. Cuz the main thing here is that I'm in SoCal and just having a CEL is an automatic fail. Even resetting it won't make u pass as their has to be some stored data in the ECU for ur car to pass emissions. I don't wanna spend 250-300 just to pass smog when the only problem is a code 31. Hell, if I were turbo, I'd pay that much for smog. But I'm only NA with minor bolt-ons...

Mikey, I've been able to pass fine with no downstream o2 sensor (CEL code 21). I just reset the ECU before going, and drive real hard for 5 mins on the way. The last place was a test-only place too. I think just driving really hard for 5 mins (for me it was more like 3) will gather enough data, because they hooked it up to my ECU and it passed fine.

SonicYan aka Mikey
1997 Eclipse RS
Pinoy Reppin' SoCal 2GNT
Best: 16.35 @ 83.05 MPH

another one bites the dust
i swear that check engine light is the most aggravating thing..
i wanna just rip out like my ecu and throw it at someone in the dealership
anyhow, check engine light came on first time in 3 yrs of owning the car i get autozone to delete it and it comes back 2 days later

did you ever bring it to the dealer to check? i think thats what i am about to do. any thoughts on that?

yes, thats how desperate i am to getting rid of it. can't be that bad, i should get a warranty for any dealer work right?

Dealer will charge you ~$100 to check it. If it's covered under your warranty, the cost goes into the total cost and you just pay your deductible (if any). If it is not covered by warranty, you will get stuck with the bill for the diagnostics. Have fun with that route. I almost gaurantee you the "part will have to be ordered."

I am interested in this valve xtremeRS posted. Do you have pics or a link to a diagram of this? Maybe some more specifics sir? I'm betting money on this one too.

TIA!

i dunno if this is related at all but i hear ticking noises from the passenger side. sounds as if its right next to me. also saw black soot splattered between the fender and the door on the passenger side also. can a leak do that if its by that area? does the ticking have anything to do with the lea? (if thats what it really is) and i don't know if it was me or whatnot but after i put gas in today, i heard sloshing from the passenger side after i drove a couple of feet out of the gas station. this is weird.

bump

the soot is likely just grease used on the hinge which collects dust after so long. All the evap stuff is in front of the tire on the pass side front. You can hear gas sloshing around sometimes. After all, the gas tank sits about 1 ft or less behind you man.

will the evap problem cause my car to rev by itself? meaning during warm up, it will fluctuate between 800-1500 rpm and whats worse, when in drive and stopped at a light, the car will want to go by itself without me stepping on the gas which makes me step on the brakes harder to keep it from rear ending people. damn, i m going bald because of the evap and idle problem and i can't get it really checked for another 2 weeks, i need the transportation.

Ok, this valve is located under the car, down the middle centerline sort of, right on the underbody, between the gas tank, and the spare tire well. It will have like 3 or 4 vac lines going into it, and a round shaped body, with a round cap ontop of it. If you are boosted and have this cel code, I'd bet money its this valve. I have already taken mine apart, and sure enough it was torn inside. I just put it back on because i didnt want to order a new one at the time..that and i have an EGR CEL that wont go away, so I really dont care

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

SO you don't have to drop the tank? SWEET! I did see in the drawings (the ones on the main page for part numbers or whatever) what looked like one at the base of the fuel fill tube. Is this a different location for different years? And finally, sir, what are the chances that this could be the case on a NA car? Thanks!

That'll give you a hunting idle, too, if the diaphragm is ruptured. When it tries to create negative pressure in the tank (with manifold vacuum), that diaphragm seperates the tank from atmosphere. Instead of pulling air out of the tank, it winds up pulling air out of, well, the air. This is a vacuum leak, by definition.

-=B-=

Dude, Boeing called. They want their wing back.

Dark0ne95: There is a butthole on that girl that his going to feel the wrath of 23 yeras of worldwide hate.
Me: Can I put that in my sig?
Dark0ne95: GO right fucking ahead.

There is supposed to be a decal under the hood showing the layout of the vac lines and all that, but if you have your car at Satan to get this fixed, it had damn sure be under warranty imo. They are not going to be able to find this leak. I think it moves based on whatever is malfunctioning. I bet they tell you the tank needs to be replaced and have the EVAP components. An easy $2000 for someone who just can't find the leak.

I have this CEL come up 3 times when I do the keydance and it still does nothing bad. I say don't sweat it. I do have the hunting idle though. I may get under the rear end this weekend and see what I can see, eh?

The diagrams I referred to above are on the main page, but some fucking ass ram dipshits decided to hack the main page and I don't know if it's back up yet. If it is, look around up there and you should be able to find it. It's called CAPS or something.

Lata

The EVAP system starts at the gas tank with the roll over valve. vacuum lines and vent lines comes up to the engine bay and off to teh charcoal canister which filter the gas fumes to vent. The solenoid and other EVAP junk is up front behind the bumper on the passenger side.

The roll over valve itself is junk from what I hear, I doubt you have to be boosted for it to break. Mine may be toast, I pulled the code when I got emissions tested. There's also the possability I smoked out teh charcoal anister running as rich as I have and being untuned with a bad O2 for a while. I'll get under there and check the valve eventually.



http://www.exileracing.com
una salus victus
Mods List: http://highlander.dsmpower.com/sig.htm

any real pictures? the CAPS looks really confusing to me. also, is there a safe way to totally erase the evap system from the ecu?

Yes I did. Replace your canister vent valve. It has a weak diaphram. This part is less than $15. I have a pics where it is located. Can somebody help me post this pix? Well anyways, Two years ago I have this problem when I installed a turbo kit. I almost replace all the parts for my evap system. When I got to this parts, my problem went away, then, after a couple of months it came back. Then I changed this. I finally put a one way check valve in between the vacuum. It's been two years now with out that evap problem.

email me the pictures sir.

brian.driggs@homestore.com

I can host them. I want to see where this check valve is located just in case I cant get to the rollover or whatever on the tank.

:thumsbup

Thanks to JUNJUN for the picture and to KaptainMyke for the hosting.
http://www.kaptainmyke.com/forums/index.php?act=Attach&type=post&id=17723
1) I assume the control line (#6) is the vac line here.
2) does this all just come up out of that access port? Or will there be more work involved? I thought you had to drop the tank in order to access these bits.

Thanks!

Wait. It occurs to me in looking at that picture a little longer that that isn't our system man. Our EVAP cannister is under the front right fender. This was a useless diagram now that I look at it.

This diagram is from a 99 GS eclipse, my car. I assumed that yours probably has the same parts but in different location

so DR1665, we have different parts? as for that piece, how do i access it if its the same? any major tools involved? where are you guys anyways? if your in NYC maybe you can help me but i doubt it. worth a shot asking tho.

JUNJUN, if possible, can you take real pics? sorry to bother. thanks tho.

That diagram just confuses me. On any 2GNT, this should all be in the same location. What's throwing me off with that diagram is the thing below the assy. If that's the gas tank, it's not our car that I can tell. Our rollover valve is located on top of the gas tank. Can anyone else take a look at that diagram and confirm?

Thanks!

ok, i found a pinched hose but i have yet to unplug the battery to reset. figure i would do it in the morning when the car is cold so the ECU would go through the whole learning curve from cold to warm. question is, would the engine light go off by itself if the problenm was that pinched hose? or should i reset it by unplugging the battery?

bump

This valve I'm referring to is not the "rollover" valve. YOu can see it clear as day, if you get under your car, and you will see the big divot from the spare tire well, and then the gastank. Right inbetween these two things, almost right in the center, will be this valve. The pic posted is pretty accurate. I dont know if the part is the same on the 95-96, or what..its on my 98..

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Thanks Xtreme. :thumsbup

Here's my solution.

I always had a check engine light related to the EVAP system ever since I installed my turbo 4-5 years ago. Anyways, this last summer after installing my rebuilt engine, instead of reconnecting the EVAP system by way of the vacuum lines in both the TB and the back of the intake manny barb, I merely left both lines disconnected from the EVAP and plugged up the TB. Guess what? I no longer get a code related to the EVAP system.

Sure, the EVAP system doesn't work and I still have a CEL for the EGR, but my VERY senstive 98 ECU no longer has a trouble code for the EVAP.

It's been that way for 6 months now.

_____________________________________
Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)

So you just unplugged the lines going into the cannister then?

Intersting idea for a quick fix until I have the funds to start replacing solenoids again. :p

_____________________________________
Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)

Werd.
I will give this a shot over the weekend for sure. I need to get rid of my 3 CELs for the 31 code. That would bring me down to only 6 codes.

I'll give that a shot Jason, if my EVAP code comes back here soon, so I may actually pass OBD emissions and not have to dyno. Thanks.

The vacuum line off the manifold should be the one with the check valve in it.

You can use vacuum caps to cover the vacuum nipples. You can get tham at any auto parts store.



Exile Racing Technologies: http://www.exileracing.com
una salus victus
Mods List: http://highlander.dsmpower.com/sig.htm

The rubber lines slide over metal hard lines that go into the EVAP system. You can pull them all the way out and cap them there.



Exile Racing Technologies: http://www.exileracing.com
una salus victus
Mods List: http://highlander.dsmpower.com/sig.htm

is there a way to totally erase the evap system from the ecu so that the light never comes on for it and will pass emissions?

dr1665, did you try it yet and how is it working for you?

well i found out that with the ports plugged up as mentioned above, i no longer get p0442, small evap leak, i now get a code associated with the leak detection pump. does that narrow down the problem?

Keep at it. I have bigger fish to fry. I have the code 3 times amongst several others and I have a lot of shit I need to fix. First thing I buy with the tax refund this year is a Larson Hose Kit from RRE. In yellow, since I'm all motor and need the yellow power.

is it even possible to have the evap system erased from the ecu?

bump

On this one year anniversary since the last post to this thread, two more guys found solutions to CEL 31. http://www.automotiveforums.com/vbulletin/showthread.php?p=2692411

ROYBOY

can someone give me a brief on the two latest solutions to code 31.
I tried clicking that link above and it isn't working for me.

Thanks

-Vent on top of gastank leaking (might refer to rollover valve)
-Replaced vapor canister

Both of which were already discussed in this thread: http://forums.2gnt.com/dcboard.php?az=show_topic&forum=23&topic_id=769