Evap issues - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 08-21-2014, 05:09 PM   #1
Jeeper
 
Join Date: Aug 2014
Posts: 22
Evap issues

So im getting evap codes on my jeep. So far i have replaced the gas cap (OEM) and the evap purge selonoid. The codes kept coming back took it to get smoke tested and the only place it smoked was the LDP filter (black cylinder by the charcoal canister ). Im not sure if that means the LDP needs replaced or not im not throwing any LDP codes (if those are real things)

KilzZombies is offline   Quote Quick Reply
Old 08-21-2014, 05:44 PM   #2
Supporting Member

WF Supporting Member
 
Ryan Angela's Avatar
 
Join Date: Sep 2013
Location: Yorkville IL
Posts: 628
Chased the large leak code for awhile. Shop did a smoke test, and discovered the LDP was mud packed. They cleaned it, no code since!

__________________
'01 60th anniversary ed. TJ 4.0 auto, 2.5" RC SL, 1" MML, 31x10.5x15 Duratracs, weekend toy.
Ryan Angela is offline   Quote Quick Reply
Old 08-21-2014, 06:26 PM   #3
Jeeper
 
Join Date: Aug 2014
Posts: 22
I will pull it and see if it needs cleaned out. I wouldn't be overly concerned except PA emissions. Hopefully a cleaning will help as a new one is 110 and im already 200 deep in this fix.
KilzZombies is offline   Quote Quick Reply
Old 08-21-2014, 06:31 PM   #4
Supporting Member

WF Supporting Member
 
Ryan Angela's Avatar
 
Join Date: Sep 2013
Location: Yorkville IL
Posts: 628
I was quoted almost $200 for a new one, they cleaned mine for free. Can't hurt to try!
__________________
'01 60th anniversary ed. TJ 4.0 auto, 2.5" RC SL, 1" MML, 31x10.5x15 Duratracs, weekend toy.
Ryan Angela is offline   Quote Quick Reply
Old 08-21-2014, 06:36 PM   #5
Jeeper
 
Join Date: Aug 2014
Posts: 22
Def will and yeah 200 from the dealer prolly for one...rock auto has one for 110 i believe
KilzZombies is offline   Quote Quick Reply
Old 08-21-2014, 07:06 PM   #6
Jeeper
 
Join Date: Aug 2014
Posts: 22
So pulled it lut amd its clean as a whistle...but it appears the previous owner may have tried that already as the top part near the clips had broken chunks in the plastic...might be time for a new one...
KilzZombies is offline   Quote Quick Reply
Old 08-21-2014, 07:16 PM   #7
Jeeper
 
Join Date: Jul 2014
Posts: 219
What year is this jeep are we talking about? Which engine?
c.d.c. is offline   Quote Quick Reply
Old 08-21-2014, 08:00 PM   #8
Jeeper
 
Join Date: Jul 2014
Location: Long Beach CA
Posts: 108
I had three Evap. codes myself last week and ALL my hoses are starting to crack. I changed out one (ouch) and painted the ends of all the rest of them with rubber paint and put on a new gas cap (the cap did not help). I crawled under the gas tank and felt that hose and managed to reach up there and paint that one as well without dropping the tank and all the codes are gone now after disconnecting and reconnecting the battery.

First time the engine light's been off in about a year.
hapgood is offline   Quote Quick Reply
Old 08-21-2014, 08:39 PM   #9
Jeeper
 
Join Date: Aug 2014
Posts: 22
2001 tj 4.0...i had it smoke tested i assume a cracked hose would have leaked smoke only thing that leaked was the LDP filter
KilzZombies is offline   Quote Quick Reply
Old 08-21-2014, 11:29 PM   #10
Jeeper
 
Join Date: Jul 2014
Posts: 219
Did the person that was smoking the system know how to properly Diagnose and smoke an LDP style EVAP system?
Did you smoke check it with the key off or on,engine running or not?

If you smoke the system without closing the canister vent valve (which is part of the LDP) then it would be normal for smoke to come out of the LDP filter. You must be sure to close the LDP vent valve, only then will the smoke build pressure in the rest of the system and show you if there are any leaks.

I don't know if all LDP's are created equal, but I was testing the EVAP on a 2003 Chrysler product yesterday and it required me to pull a vacuum on the diaphragm part of the LDP and ground one of the wires to close the vent valve. The alternative to finding the correct wire to ground and applying vacuum is to pinch off the hose going to the LDP filter and then smoke check it. The only problem with this method is that you can not test the vent valve in the LDP but it is quick and easy to do to see if there are other leaks in the system.
c.d.c. is offline   Quote Quick Reply
Old 08-22-2014, 09:35 AM   #11
Jeeper
 
Join Date: Aug 2014
Posts: 22
I think they tried to jump the vent valve and said the couldn't get it to close but they told me it was the purge solenoid which i jumped myself and heard it working...so maybe he meaty he couldn't get the LDP to close properly and called it the wrong thing
KilzZombies is offline   Quote Quick Reply
Old 08-22-2014, 12:12 PM   #12
Jeeper
 
Join Date: Jul 2014
Posts: 219
The vent valve is inside the LDP, so they are one in the same. The LDP/vent valve is open in its rest position, it needs vacuum at the diaphragm and a power and ground signal from the computer to close the valve. The purge valve is smaller than the LDP and only has two hoses going to it, one to the intake the other to the canister. In it's rest position the purge valve is closed.

To seal the system for a smoke test, unplug the purge valve electrical connector so the ECM does not open it. Start the engine and make sure there is a good vacuum supply from the intake to the LDP (or use a hand held vacuum pump instead of engine vacuum), now ground the middle wire in the LDP electrical connector. The system will now be sealed and you can smoke check it properly.
c.d.c. is offline   Quote Quick Reply
Old 08-22-2014, 01:34 PM   #13
Jeeper
 
Join Date: Aug 2014
Posts: 22
So unplug purge solenoid and run engine with LDP still plugged in or do i need to apply current myself? Then smoke test
KilzZombies is offline   Quote Quick Reply
Old 08-22-2014, 02:13 PM   #14
Jeeper
 
Join Date: Jul 2014
Posts: 219
Yes, leave the LDP plugged in, this will supply the power to it but you will need to ground it yourself on the middle wire of the connector.

Apply the smoke into the EVAP access port if you have the adapter, or at the hose going from purge valve to the canister on the purge valve side of the hose.

Check the entire system for leaks, all the way back around the gas tank and up the fuel filler neck to the gas cap. With the LDP/vent closed there should be no smoke anywhere. Then pump smoke through the purge valve to check that it is not leaking either.

Once you rule out leaks then you can do further LDP testing and check for electrical issues.

Assuming the gas cap is tight the #1 most common cause of EVAP codes on jeeps is leaking hoses, #2 is LDP. That said there are other possible causes as well.
c.d.c. is offline   Quote Quick Reply
Old 08-27-2014, 08:56 AM   #15
Jeeper
 
Join Date: Aug 2014
Posts: 22
To update all I took the jeep to get it retested and asked if they had properly done the LDP. They retested it for free for me and found that the motor wasn't working properly on the pump. It would click off and on. So they then manually closed the hose off to finish the test. And there is a leake "somewhere near the gas tank" i asked if they could be more specific and they said without dropping the tank it was to hard to tell. They suggested 3 lines that run to the tank or the O-ring for the fuel pump be checked....at least we now have some direction here...
KilzZombies is offline   Quote Quick Reply
Old 08-27-2014, 12:29 PM   #16
Jeeper
 
GeePStrings's Avatar
 
Join Date: Aug 2011
Location: Twinsburg,OH
Posts: 169
Quote:
Originally Posted by KilzZombies View Post
To update all I took the jeep to get it retested and asked if they had properly done the LDP. They retested it for free for me and found that the motor wasn't working properly on the pump. It would click off and on. So they then manually closed the hose off to finish the test. And there is a leake "somewhere near the gas tank" i asked if they could be more specific and they said without dropping the tank it was to hard to tell. They suggested 3 lines that run to the tank or the O-ring for the fuel pump be checked....at least we now have some direction here...
I just dropped the tank on my 99 last week to address the large leak code. There actually is only one evap line running to the tank. It runs along the driver side. It's a 3/16 rubber hose from about the back wheel to the tank. That hose connects to a plastic Y connector that has (2) 1/4 outlets. The 1/4" outlets on the Y connector then have a 1/4 inch rubber hose going to the left and right side of the top of the tank and connect to breather ports. Those breather ports appear to be glued onto the tank.

In my case the problem was the Y connector itself. This $2 part snapped off at the 3/16" port that heads up to the engine. After digging in I concluded that the PO replaced the fuel pump and probably failed to disconnect the 3/16 hose when lowering the tank. Tank came down and the little nipple snapped off because the hose was tie wrapped to the frame.

If you tackle this yourself like I did just know that you can lower the tank a few inches and see the top of the tank and inspect the lines and plastic ports. While I had mine down I bought and replaced the 1/4" hose (2ft piece is plenty) and then replaced the 1/4 -1/4 - 3/16 connector with one I bought from Advance Auto. I went ahead and replaced my rusted gas tank mount and straps as well! Use a jack to lower your tank, hand tools to loosen the 7 nuts. If you struggle with any rusted nuts know that the 3 above the axle are connected to carriage bolts that can be easily replaced. Lots of PB Blaster resulted in only one replaced bolt! I'm no mechanic by any stretch and was able to do 100% on my own in 6 hours.
GeePStrings is offline   Quote Quick Reply
Old 08-27-2014, 01:02 PM   #17
Jeeper
 
Join Date: Jul 2014
Location: Long Beach CA
Posts: 108
I guess one way to test the tank hose would be to just pinch it off with a small clamp and see if the code comes back after clearing it and if not - if it comes back after taking the clamp off.
hapgood is offline   Quote Quick Reply
Old 08-27-2014, 01:18 PM   #18
Jeeper
 
Join Date: Jul 2014
Posts: 219
Quote:
Originally Posted by KilzZombies View Post
To update all I took the jeep to get it retested and asked if they had properly done the LDP. They retested it for free for me and found that the motor wasn't working properly on the pump. It would click off and on. So they then manually closed the hose off to finish the test. And there is a leake "somewhere near the gas tank" i asked if they could be more specific and they said without dropping the tank it was to hard to tell. They suggested 3 lines that run to the tank or the O-ring for the fuel pump be checked....at least we now have some direction here...
The LDP does not have a motor inside of it. It is a pump but not an electric pump, not like a fuel pump for example. It uses engine vacuum and an electric solenoid to move a diaphragm which is the pump.

It would appear as though the place you are having do the leak test is not familiar with how your EVAP system functions, therefore they will not be able to accurately diagnose it with out resorting to throwing parts at it. That said, if there is a leak at the tank this is where you should start your repairs.
c.d.c. is offline   Quote Quick Reply
Old 08-27-2014, 02:45 PM   #19
Jeeper
 
Join Date: Aug 2014
Posts: 22
The electric solenoid is what was clicking. That is my fault for using incorrect terminology. They hooked it to a battery and i could hear it clicking and then a good one so i could hear how it stayed on. I am starting at the rear though to see what is leaking back there
KilzZombies is offline   Quote Quick Reply
Old 09-30-2014, 07:27 AM   #20
Jeeper
 
GeePStrings's Avatar
 
Join Date: Aug 2011
Location: Twinsburg,OH
Posts: 169
KilzZombies - any luck with finding your issue? Wanted to let you know that I ended up purchasing a hand pressure gauge (brake bleeder) and used it to test each segment of my evap. Someone suggested the pump on this site. Here's how i did it:

1-Top off your tank
2 - pull the rubber 3/16 hose off the metal line on drivers side near rear axle
3 - attach pump on tank side and pump it until you start to see the needle rise above 0. This will take quite a while (15 mins) since you are essentially sucking out the air from all the dead air spots on top of the tank. Once you register some vacuum let it sit a few minutes to validate it holds the vacuum. This should prove if the tank and evap hoses on your tank are good. Be aware that if you cannot get it to hold a vacuum you probably have a leak at the pump or associated evap hoses. If you pump for days and cant get it to hold a vacuum you probably have a large leak somewhere on the tank or on the components.

If tank proves good . . .

4 - plug off the metal evap up near the firewall and test end to end on that metal line. If it's solid you'll achieve pressure after 1 or 2 pumps. This is where one of my 3 gross leaks was found. I could actually hear the vacuum whistle each time I pumped.

5 - by now you should get the picture. Isolate each section of hose to validate the integrity of each piece. Keep testing all the way through your engine compartment.

One important thing that never clued me into my rotted evap line - I always smelled fresh fuel when I would turn my Jeep off. I just never thought anything of it. Now, I dont smell fresh fuel. Hope this helps.
GeePStrings is offline   Quote Quick Reply
Old 10-01-2014, 06:11 AM   #21
Jeeper
 
Join Date: Aug 2014
Posts: 22
I ended up replacing all the rubber lines to the tank to fix the rear leak as I threw a different code after I replaced the LDP. All in all I'm finally inspected after lots of emissions headaches left for my by a previous owner. Thanks everyone for the assistance.

KilzZombies is offline   Quote Quick Reply
Reply

Tags
evap , ldp , leak detection pump

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Download our Mobile App

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 12:28 AM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC