cpnwrench

Ok Folks, This is gonna be a weird one…………..I’ll describe the best I can, maybe Walker, Cruiser or Donnie can help me out here on this bizarre problem……and my apologies for the length of this post!

I had previously posted about a fuel smell in the cabin when driving and the fuel level gets at or near to a ¼ tank.
Today I went through the underside and engine compartment with a flashlight and mirror and checking the vacuum diagram posted on the label mounted to the firewall.

Here is what I discovered………

According to the diagram on the jeep label.. the vapor canister is ”supposed” to have three vacuum lines from it… 1 to the air box (airfilter box) which it does (check), 1 to the intake manifold which it does (check), and 1 to the fuel tank fuel vapor valve which it does not (no-check).
Here is where it gets strange, and straighten me out here…….
The line (small diameter rubber hose) from the fuel tank fuel vapor valve runs up to a “hard-line” at the rear axle. From there the “hard-line” runs up to the front of the Jeep alongside the fuel supply and fuel return and rear brake line. At the front of the Jeep (on the underside still on the drivers side of the engine where it meets the transmission it runs up and to near the top of the firewall). It then bends 90 degrees toward the passenger side for about 2 inches then has ANOTHER rubber hose attached to it, and continues across the firewall then DOWN alongside the bell housing (passenger side now), where it connects to a short piece of “hard-line” again (about 2 inches in length). This hard line has a small bracket welded to it (supposedly to attach to the bell housing as a stand-off to keep from contacting hot metal parts!). Now, the other end of the short piece of “hard-line” has another piece of rubber hose on it and this now travels back along transmission then up and over on top of the transfer case (NP231) to a vent tube going into the transfer case…..

I found that this section of tube was loose, as I wiggled it and heard vapor hissing out of it and it smelled like gas.

Background; it has been like this a VERY VERY long time.
I am going to replace this rubber hose from that 90 degree bend at firewall all the way to the transfer case vent tube if that’s correct,,,BUT……

OK NOW,,,,, here is the question(s)……
Because I have 4 wheel drive and the NP231 xfer case, is this the correct routing for the fuel vapor vent tube into the transfer case? Wouldn’t those fumes cause problems in the transfer case? Or is the vent tube on the top of the NP231 just that, a vent tube, not a vacuum source?

Cuz right now I DO NOT have any hose for the THIRD connection on the charcoal vapor canister to travel back to the fuel tank as shown on the manufacturer label on fire wall.
Also, I do not see anywhere where there would have been a T-section or even an additional hose for the transfer case for vacuum at the intake manifold etc etc.

I cannot find anything(write-ups, documentation, etc) on the tube coming out of the transfer case so forgive my ignorance on this.

The truly funny thing about ALL of this is the Jeep runs great…..’cept for the smell as I said. And now I am now starting to see a leak of transfer case oil at the yoke section at the rear of the transfer case where the driveshaft attaches. First leak I have had in 10 years….

Regardless, can anyone tell me what is what with this?

I really would appreciate your help!

Thanks guys!

Oh yeah, I am going to try and edit and post some pics, tough to get them shot those cuz of tight space locations.

freegdr

the tc case vent is just that a vent should no connect to anything but atmosphere

cpnwrench

Well crap,,,,,, think I know what happened here.....

"Sherman, set the wayback!".............

circa 2005......cross country camping expedition with my then 9 years old...
LOOOOOONG trip.....anyway leaving Yosemite to San diego to visit my brother, clutch felt spongy..... so when i am at brothers house we decide we are going to flush and fill the clutch slave cylinder...when we do this, the slave cylinder just plain failed, resulting in me having to get it towed to a shop my brother frequents (or so he says, rrrrrgh)....

yeah, new slave cyl and clutch later (as I had no tools and on a schedule with my son...yadayadayada......

400 dollars later new slave cylinder, clutch,, everything is good.

NOW I KNOW WHAT HAPPENED.........

techs after reassembly attached what they thought were correct vacuum hoses at proper spot. and connected vent tube to my fuel evaporator line.

Switch to present:
found obscure drawing in haynes,,,,looks like vent tube is JUST that a vent tube, however, it does show it without any destination...going to presume that its designed that way to vent it up and out of any water/mud/snow/sand......

so guys hope one of ya can verify my findings....

sorry for the previous long post.!!!!

will let you all know what happens tomorrow when i fix it the way its supposed to be!

Looks like I gotta replace that rear yoke oil seal too while I am in there.

what a dumb a$$ I am.

cheers!

cpnwrench

cpnwrench

Thanks Free!!!! verification acknowledged!

knee deep in Cpn Morgan now.......researchin my error!

will fix tomorrow after work! and post results!

cheers!

cpnwrench

Slick761

Yes they hooked it up wrong, yes the vent should just run into engine bay, and did you have any sort of high idle issues? If it was vacuum in you would suck those vapors to your intake probably in 4. Did your 4x4 indicator work and did your disco engage?

cpnwrench

Hey Slick.....yeah its funny, guess I shoulda checked the work back then

yeah right....with a 9 year old and campin gear out the wazooo and places to see!

anyway.....

believe it or not, the Jeep has been running absolutely great......again except for the gas smell the past couple years.

and for 4 wheel, no problems in 4 hi, little tough in 4 lo, but once I am moving it goes in.

am really guessing the fuel vapors goin directly into the vent of the xfer may have caused the thinning/deterioration of that rear seal over time.

ahh well, lesson learned and thanks for the reply! I appreciate it!

cpnwrench

Slick761

Ya prob wanna change the fluid. Just makin sure it was the vent and not part of the vacuum system.... you do have a disco right? If not I'm floating. Sometimes I get confused. Havnt felt like thinkin lately.

cpnwrench

Well its the NP231 and according to drawing I am looking at, it has a vent tube and vacuum switch.

I have the 5 speed manual ax15 and the 4 wheel engagement is the lever at console which goes from 2wd to N to 4H to 4L.

I usually shift to 4x when I am not moving, but read somewheres' here that, that guy at that place with that thing for them folks had said you can shift into 4x when drivin along.

so as to whether or not I got the disco, I dont think so. whenever I go back to 2x it goes in just fine.

so I just think I have been feedin them gears in the xfer a lotta gas!

crap!

an yeah , gonna tackle the rear seal this weekend. I hate leaks!
cheers and thanks for the support!

cpnwrench

cpnwrench

one last thing......when i go and change out the real seal on the transfer case...according to haynes it asks for Dexron II or Mercon as the lubricant..

any input on this? or go with it.

thanks!

cpnwrench

Slick761

That's correct. Simple trans fluid.

cruiser54

Yeah, shift into 2H or 4H while moving, 4L at a stop after it's already in 4H.

Take a look and see if you have a disco front axle, will ya?

And the difficulty shifting out of 4WD is never caused by the disco axle. All the disco axle can do to screw you up is NOT engage when 4WD is selected with the transfer case lever. That usually happens when you need 4WD the most BTW.

cpnwrench

AMAZING what $3.18 worth of new hose can fix!!!!


so now my transfer case no longer has noxious fumes being fed into it, AND my fuel vent line is ACTUALLY going from the fuel tank to the charcoal canister!!!!!

An guess what? no more F-n smell!!!!!!

another little tidbit.......no gas/vapor pressure when I unscrew the gas cap!!!

Now this is rather freaky, as ANOTHER benefit of having the hoses routed to the CORRECT place,,,,,the Jeep (god bless her), actually idles much quieter! how does that happen?

this weekend will be the test of the 4wd system, to see if I still have the 2wd to 4wd L problem (not really a problem, more just a nuisance than anything else).

SO everyone thanks for the input, looks like I will be after the rear yoke seal on the transfer case this weekend.....hope all those gas fumes did not deteriorate too much stuff inside the xfer....

cheers! an thanks again!

cpnwrench

gonna celebrate (again w/some morgan!!!!)

BassMasterCHS

I have the same issue but my evaporator is capped off at the small post off to the side. Should I remove the cap somehow and hook it up to the hardline near the master cylinder?