Evap. System

My wifes 01 was throwing codes that led me to believe she wasn't tightening the gas cap enough. I got an OEM cap from the dealer. Pulled codes on it this morning and they are P0442 (Small leak) and P0455 (Large leak). The vehicle has 40,000 on it.

The Haynes has a diagram for the system so I guess I'll check all things in the diagram (MAP, EGR, Evap. canister, etc.). I thought the last time the code popped up, the layout of the components in the vehicle were different than the diagram but I can't recall.

If I'm not dealing with a leaky hose or something kind of obvious, how can I determine the problem? Someone had mentioned some kind of pump but I can't find much on things to check for these codes. Thanks.

-Chris

evap cannister is down in front of the rear axle up against the body. I'd start looking for disconnected hoses or hoses that might have been bent over while it was being worked on.

Well it looks like the canister has 3 hoses that come off it. The lower one in the pic connects to a fuel line that runs to the tank.


The middle hose in the pic connects to a smaller diameter plastic line that runs up to the front, along the firewall and ends next to the green cap shown:



The upper hose connects to a larger plastic line that runs the same and ends here:

Same area...I just don't know the name of the part that it connects to.

The middle hose in the first pic has some tiny dry rot cracks in it but I'm not sure if that could cause the problem. I guess I could pull it off and go get a new piece and see what happens. Otherwise, I just don't know what to look for. I know some problems are difficult for you all to help with by internet. I just hate taking it to someone. Looking for advice.

Anyone know if these leaks are something that I would be able to track down while it's running? If it's coming from a hose, I thought it might smell or bubble up if I sprayed Windex on it. If it's one of the pieces in the system, I don't see any tests to run.

just to resurrect the dead...

My '00 popped P0456 and P0442 this morning. Any chance of finding the pics that are no longer in this thread?

How funny that you should ask. She came home 2 nights ago and said that her CEL had come on while driving home from work. I scanned it and got PO456 (deals with another leak in the evap. system, SMALL LEAK). I cleared the codes on it and tightened the gas cap about 5 clicks. As of last night, it had not come back on again. If it does come back again, I will be dealing with it this weekend. I can get you pics of the area probably tonight. The MAJOR LEAK she had (I think PO455) turned out to be about a half inch cut in the middle hose on the evap canister. The dealer sells the 90* hose that comes off the canister already attached to the plastic line that runs to the firewall. I just used some fuel hose that was bent and used hose clamps.

-river

awesome, thanks for the fast response. I'll be checking that out this afternoon and post my finds.

i just checked out the pics I originally posted again. I think the one that is missing is just a close up shot of the second pic. You're basically looking for cracks in those stupid hoses. I would def. start at that evap canister though.

tinypic is down in most of the US Can you post them here? http://auctionsuite.com/48hr_uploader.php

OK...I messed with the 01 today. I'm updating this thread b/c there really isn't much in the archives about the Evap. system. 6 months ago I dealt with a gross leak in the system and it ended up being one of the rubber elbows that comes off the canister near the rear axle. This time it was a small leak. I think they're all gross b/c they're a PITA to track down.

When checking this system, I'm 2 for 2 now with rotted rubber hoses so I think it's safe to start there. There are 3 small hoses that come off the canister located on the underside of the vehicle near the rear axle (as shown in above pics). Check those thoroughly. I used a telescoping mirror and flashlight to see all the way around each one. This time they were good. Only one of the lines coming off the canister leads back to the gas tank. Just in front of the tank there will be a 3-4 inch rubber tube that connects 2 metal lines together. Check that for cracks.

The other 2 lines coming off the canister lead to the front and follow the drivers frame rail all the way up. The lines are plastic after the rubber elbows that come off the canister. Just behind the front wheel there is 3" section of straight hose that connects the plastic line to a metal line. The metal line will run up the firewall right under the master cylinder. The small 3" rubber tube was cracked and dry rotted. The metal line connects to another plastic line about halfway up the firewall. There is another straight rubber hose there. This one was also cracked today. I used 1/4" fuel line as a replacement. It was a tight fit so I used some Vaseline (I just happened to have some nearby for some uh.......other work that I was doing).

At this point that plastic line runs along the firewall over to where AC stuff is. It connects with another rubber hose to a solenoid that is also part of the system. That hose actually looked OK so I left it alone. So there ya go. Not too horrible I guess. I cleared the codes in the ECU and we'll see what happens in a few days.

-river

I've got the same problems, and am looking for a hose that will last longer than the stock rubber did. Anyone have a suggestion?

All I did was go to NAPA and get rubber hose of the appropriate size. It's worked fine. I can't really see having an issue for a long time. I did use some small hose clamps and gently secured the hoses to the plastic lines. Careful though...don't wanna crush the plastic.

riverfever said:

All I did was go to NAPA and get rubber hose of the appropriate size. It's worked fine. I can't really see having an issue for a long time. I did use some small hose clamps and gently secured the hoses to the plastic lines. Careful though...don't wanna crush the plastic.

Click to expand...

Great thread...
Anyway you could update the thread with approximate lengths and sizes of rubber hose needed? I'd love a shopping list of stuff to get so I can hopefully take care of this problem once and for all.

Thanks

Wow...it's been a while but I'll try. The section of hose that comes off the middle connection on the evap canister was the most particular one. You've got to get the elbow in that piece close to stock as well as the diameter. Best bet on that one is to remove the old and go in. They let me root around a box of scrap and I found just what I needed for that.

The other spots that I replaced were much easier. Along the frame rail and up by the firewall you will find the rest of the lines that make up the evap system. They are essentially black vaccum lines. Every once in a while there is a short section (4") of rubber hose. That's where the cracks will be. I used 5/16" fuel line to replace about 4 of those sections. There's one that's halfway up the firewall towards the drivers side that was really trashed and it's a PITA to get at. That's it. The hardest part about these codes is tracking down where the leak is. It's just time. The biggest crack I found was probably 1/4" and the small ones were just bad dry rot cracks. I hope this helps.

Well I was able to get to them all but the firewall one you mentioned...I didn't even see it. I'll have to check again. I replaced a bunch as they were very dry rotted, but none seemed to be an obvious vac leak. I replaced a couple elbows right at the intake manifold which were bad.

I reset the CEL and it came on within two starts. UGH! I'm going to look to the one on the firewall but what else besides the hoses would cause P0455?

That darn EVAP system!!!!! ARGH

I've had problems with mine a lot.. I had a large leak (forget code), and that was like 2 years ago.. Dealer cost me like 350 to replace the evap canister for me.
Good for a while, and probably a year and a half ago I started getting a code for a small leak and it would go off and on for like a year.

But it seemed to correct it itself, knock on wood.

aside from the lines leaking, you would be looking for a big leak in the filler neck for the gas tank, a leak in the evap. canister, or a leak at the canister purge valve (third picture in thread). IIRC, I also read somewhere on here that there is an air pump (electric) that pressures the system for the ECU to run it's diagnostic check that can fail and give you the P0455 code as well.

--Shorty

I think I'm going to try to get it smoked. I'd rather pay $70 and know where/if it is leaking than start replacing all these things blindly.

grrrr

This won't find your leak, but just so you get some insight into the archaic nature of when the light comes on ...the EVAP purge doesn't occur when the tank is too full or too empty. This is one of the 'ready' states for the OBDII inspection in PA. You're allowed ONE check on a "good trip" to not be tested. Since my son had the infamous header pre-cats go bad on him, I could reset the codes and THAT test could be the ONE to not be cleared to allow the IM badge to be attached. Unfortunately, he had filled the tank and that won't allow the EVAP PURGE to occur. So, we had to drive the tank below 3/4 and then do a cold start and pray that the O2 heater test didn't expire and throw another code.

It can take a few days for this code to show if you've had a loose cap. Luckily for me, that's all it was on my wife's 99 Wrangler.

geeaea said:

This won't find your leak, but just so you get some insight into the archaic nature of when the light comes on ...the EVAP purge doesn't occur when the tank is too full or too empty. This is one of the 'ready' states for the OBDII inspection in PA. You're allowed ONE check on a "good trip" to not be tested. Since my son had the infamous header pre-cats go bad on him, I could reset the codes and THAT test could be the ONE to not be cleared to allow the IM badge to be attached. Unfortunately, he had filled the tank and that won't allow the EVAP PURGE to occur. So, we had to drive the tank below 3/4 and then do a cold start and pray that the O2 heater test didn't expire and throw another code.

It can take a few days for this code to show if you've had a loose cap. Luckily for me, that's all it was on my wife's 99 Wrangler.

Click to expand...

So are you telling me that if I fill the tank and reset the light that it might not come back on until it drops below 3/4? That would give me enough time to run the other checks through so I can get a sticker...