Jeep Wrangler Forum

Jeep Wrangler Forum (http://www.wranglerforum.com/)
-   TJ Tech Forum (http://www.wranglerforum.com/f210/)
-   -   Evaporative Emissions Leak - I NEED HELP (http://www.wranglerforum.com/f210/evaporative-emissions-leak-i-need-help-19474.html)

Wolfgang 06-25-2008 06:41 AM

Evaporative Emissions Leak - I NEED HELP
 
Here's some history:
2002 Jeep Wrangler Sport, 6 Cyl (4.0L), M/T, A/C, 46,000 miles. Wife's vehicle.

I have had more check engine lights with this vehicle than any I have ever had. Luckily, they have all been easy to remedy and nothing major - yet (knock on wood).

About a year ago, I got a check engine light shortly after an oil-change. I didn't have time to do the oil-change myself. I hooked my scanner up and got P0455 and P0442 codes - which were Evaporative Emmissions Leak (Major and Medium).

I did some checking and noticed the "tube" that connects where the PCV valve would be was loose on the other end. I pushed it back on and cleared the codes and the check engine light stayed off. I just assumed someone at the oil change facility tried to check the PCV valve and pulled this apart.
You could not change the PCV valve on our 1997 Wrangler (4 cyl) we had so I assume you cannot on this one too. If I am incorrect, please let me know.

Yesterday (06-24-08), I got another check engine light. Hooked up scanner and got the exact same codes. Oil was changed 3 weeks ago at a oil-change facility. I quickly checked under the hood because I didn't have much time and saw nothing obvious.

I find it too coincidental that I would get these codes again - even if a year later. So I am thinking something is going on. Before I start digging in, can anyone offer some tips, hints, or advice from past experience?

Anything would be greatly appreciated!

jpdocdave 06-25-2008 07:12 AM

most common cause of evap codes is: gas cap-loose, missing, or seal is bad.

Sb5551 06-25-2008 07:13 AM

When I workd as a mechanic, we had a couple people that left there gas cap off or it wasnt tightened all the way. That will cause an evap code. Are any of the heat and/or air condition settings not working (i.e only blows on the floor). This could mean that there is a vaccume line loose behind the dash, a problem I have had before. Check to see if you hear any whisteling while driving.

Wolfgang 06-25-2008 08:05 AM

Evap Emiss
 
Thanks for the reply!

After the check engine light came on, I had to complete my drive to work (and my commute back home).

On the way home, I stopped and got gas so I know the gas cap is on correctly now if it wasn't before. Should have been enough cycles for the check-engine light to go off, right? If so, then that is not it.

I don't hear any obvious "whistling" while driving. If there is, then it is very, very, very small and would cause the MAJOR LEAK CODE, correct?

All heating/AC setting are working properly. There is nothing that I notice that is out of the norm.

Any other suggestions?

Sb5551 06-25-2008 09:04 AM

For some reason I believe three complete cycles are needed to turn the check engine light off by itself. You can always reset it and see. The gas cap could be bad though if the seal has gone bad it will still leak causing a code. Ive seen gas caps on hyundai's go at about 10,000 miles multiple times. Others things to check would be the charcol canister to see if it is cracked. You are correct about the vacuume line would most likely not cause a major leak. If there is nothing obvious I would recommend just replacing the gas cap because it is the cheapest and easiest, or just resest the light and drive it a couples days making sure the cap is tight and see what happens.

Wolfgang 06-25-2008 09:13 AM

Evap Emiss
 
What would a complete cycle be? Just something in the ECU that I can't physically measure? Or turn off engine, start, turn off, start, turn off, start? Or other? (just so I know - I've always wondered how long before it reset).

I've reset the light to see if it comes back on... If it does, I'll follow your steps (IE Gas cap).

Other than taking a hammer and smashing my charcoal canister (LOL), what would cause it to crack? Heat? Never seen one crack before...

Sb5551 06-25-2008 10:10 AM

Honestly, Im am not really sure what would cause a charcol canister to break. Constant heating and cooling, rough driving. People put there jeeps through some odd situations. It is kinda rare. It could also be a crack in the tank, but it all depends on how the jeep is driven.

A drive cycle will vary depending on the car. Usually it will need a cold start, warm up completely. It may need some specific cruising speed then stop and go driving. A ford focus took me about 15 minutes of driving, while a volvo took me about four hours and 150 miles before a cycle was completed. It depends on how long it would take the computer to properly monitor all of the emissions components. Im sure some other guys can chime in here also for specificlly jeeps.

jpdocdave 06-25-2008 10:15 AM

evap codes take the longest to set, and clear on their own. they need specific requirements to set, certain temp, fuel level, and pressures. some codes require 40 cycles to clear on their own, but if the light comes on there's a prob.

like we've said, gas cap is most common, and cheap and easy. some states the emissions centers will check them for you anytime.

other causes are vacuum lines on the evap system cracked or leaking, solenoids not opening and closing correctly to purge vapors, charcoal canister, or sensors. evap systems are very complicated, and also do nothing for the vehicles drivability.

Jerry Bransford 06-25-2008 10:17 AM

You can reset it without waiting to go through the cycles by just disconnecting the battery's negative lead for 2-3 minutes. That will clear the emissions codes until triggered again. And the 4.0L doesn't have a PCV valve. :)

Sb5551 06-25-2008 10:44 AM

JP, just for my knowledge wouldnt a vacuum leak if it was major cause a drivabilty issue.

jpdocdave 06-25-2008 03:24 PM

^most evap leaks are on vacuum lines that are for the solenoids for the fuel vapors only, but it is possible. but you would most likely have other codes also, evap codes USUALLY won't set if there's other codes present.

ecu is gonna throw lean condition before evap usually. evap has more criteria, and cycles of failure before it sets. so chances are you aren't gonna have evap leak code that effects driveability, USUALLY.

Triple88a 06-26-2008 03:15 PM

Quote:

Originally Posted by Jerry Bransford (Post 240455)
And the 4.0L doesn't have a PCV valve. :)

you sure jerry? Whats that thing in the rear of the engine behind the intake tube? I know the breather that connects to the intake pipe however thats in front (to reduce confusion)...

As far as the original post goes.. do you have a body lift? Also look under your hood. Do you see the black plastic box on the drivers side of the engine bay?

see it shinning on the right of the image?
http://memimage.cardomain.com/member...31_70_full.jpg

Jerry Bransford 06-26-2008 03:16 PM

Quote:

Originally Posted by Triple88a (Post 240904)
you sure jerry?

No, I just make things up like that. ;)

Triple88a 06-26-2008 03:20 PM

Quote:

Originally Posted by Jerry Bransford (Post 240905)
No, I just make things up like that. ;)

okay.. thanks for the attitude. Now what is that thing coming out of the valve cover behind the intake pipe?

Jerry Bransford 06-26-2008 05:28 PM

Quote:

Originally Posted by Jerry Bransford (Post 240455)
And the 4.0L doesn't have a PCV valve.

Quote:

Originally Posted by Triple88a (Post 240904)
you sure jerry? Whats that thing in the rear of the engine behind the intake tube? I know the breather that connects to the intake pipe however thats in front.

Quote:

Originally Posted by Jerry Bransford (Post 240455)
No, I just make things up like that. ;)

Quote:

Originally Posted by Triple88a (Post 240906)
okay.. thanks for the attitude. Now what is that thing coming out of the valve cover behind the intake pipe?

Attitude? Sheesh. Then don't listen to me, go pull that hose off and suck/blow on it and see for yourself if there is a valve inside it. All that hose does is pass engine blowby back into the air intake to be run back through the engine. There is no PCV valve, period.

4.0l sahara 06-26-2008 05:46 PM

the 4.0 has a ccv valve it meters the flow thats all.:)

Triple88a 06-26-2008 06:03 PM

Quote:

Originally Posted by Jerry Bransford (Post 240951)
All that hose does is pass engine blowby back into the air intake to be run back through the engine.

I see.

4.0l sahara 06-26-2008 06:19 PM

here are some pics from my jeep of how it works.

first fresh clean air is drawn down threw the breather into the block.
(the front hose)
http://i74.photobucket.com/albums/i2...n/DSC09211.jpg

then flows threw the block and collects all the fumes then the valve in the back called the ccv valve meters the flow of the fumes into the intake where they will be burned up.
ccv valve
http://i74.photobucket.com/albums/i2...n/DSC09212.jpg

dusty jeep pic
http://i74.photobucket.com/albums/i2...n/DSC09210.jpg

:D

Triple88a 06-26-2008 06:27 PM

i see so thats the ccv valve then.

4.0l sahara 06-26-2008 06:32 PM

Quote:

Originally Posted by Triple88a (Post 240982)
i see so thats the ccv valve then.

yes;)

mr4x4 06-26-2008 11:26 PM

about a year ago I had that same code come on
after we checked all the vacumm hoses and the gas cap we found nothing
we ended up dropping the tank and checking that gasket witch looked fine
ended up the big plastic skrew ring that holds the fuel pump in the tank was a little loose even though we had to tap it off with a rubber mallet

just a thought that gasket is about $10 but if the ring work its self a little loose it will cause that same code

tazmann910 06-26-2008 11:49 PM

I was getting the same codes a few months ago and it ended up being the vaccuum hoses on the drivers side. It was touching the steering linkage and rubbed a hole. I replaced the hose..no more code. This is also after buying a new gas cap and some solenoid.

MOz 06-27-2008 07:22 AM

Quote:

Originally Posted by Jerry Bransford (Post 240951)
Attitude? Sheesh. Then don't listen to me, go pull that hose off and suck/blow on it and see for yourself if there is a valve inside it. All that hose does is pass engine blowby back into the air intake to be run back through the engine. There is no PCV valve, period.

The next generation...WTF?

It's one thing to not know and ask questions....

It's a completely different situation when you don't know something and then challenge someone that DOES know something....that's just ignorant and arrogant.

TRIPP, you can't always rely on the internet to learn stuff.. Sometimes you need to actually work on things to understand them. It's called experience. There is no substitute for experience.

MOz 06-27-2008 08:43 AM

We still love you TRIPP....don't stop trying.:D

tazmann910 06-27-2008 09:45 AM

Quote:

Originally Posted by MOz (Post 241190)
The next generation...WTF?

It's one thing to not know and ask questions....

It's a completely different situation when you don't know something and then challenge someone that DOES know something....that's just ignorant and arrogant.

TRIPP, you can't always rely on the internet to learn stuff.. Sometimes you need to actually work on things to understand them. It's called experience. There is no substitute for experience.

Get'em MOz...I agree 100%, if you don't know what the hell you are talking about...don't post. Jerry knows a bunch of stuff, I would trust his word over something that has been GOOGLE SEARCHED any day. The internet is not always 100% right. But someone who has ACTUALLY WHEELED A JEEP AND TURNED A WRENCH on one, might know a great deal more...damn now you got me all fired up.

MOz 06-27-2008 10:17 AM

Quote:

Originally Posted by tazmann910 (Post 241227)
Get'em MOz...I agree 100%, if you don't know what the hell you are talking about...don't post. Jerry knows a bunch of stuff, I would trust his word over something that has been GOOGLE SEARCHED any day. The internet is not always 100% right. But someone who has ACTUALLY WHEELED A JEEP AND TURNED A WRENCH on one, might know a great deal more...damn now you got me all fired up.

The younger guys really try hard and sometimes we need to temper their enthusiasm but we need to go easy on them too.... The trick is to keep them interested and informed.

OK, so we have to separate the BS from the facts too to help people out. This place gets dicey sometimes so keeping a good tone to the subject is challenging.

Try to keep it fun and supportive....How's that for a line of PC BS?

tazmann910 06-27-2008 10:20 AM

Spoken like a future moderator...

Quote:

Originally Posted by MOz (Post 241242)
The younger guys really try hard and sometimes we need to temper their enthusiasm but we need to go easy on them too.... The trick is to keep them interested and informed.

OK, so we have to separate the BS from the facts too to help people out. This place gets dicey sometimes so keeping a good tone to the subject is challenging.

Try to keep it fun and supportive....How's that for a line of PC BS?


MOz 06-27-2008 10:46 AM

Quote:

Originally Posted by tazmann910 (Post 241246)
Spoken like a future moderator...

Do you get parking for that job or maybe a sticker?

tarheel 06-27-2008 11:04 AM

Just a promise of a yet to be determined sticker:D

Wolfgang 08-11-2008 07:22 AM

Tazmann - can you narrow my search by giving more detail on which vacuum line it was? I am still getting this code and about to go over it with a fine tooth comb. I've searched before and found nothing. Obvioulsy, I missed something somewhere...


All times are GMT -5. The time now is 02:12 AM.