Vacuum / Vapor / Air Hoses Replacement

[Coreyw454]

Hey Guys, pretty much all the lines in my 85 have been messed with and/or are shot. I want to redo all of it. What is the best way to go about this. Just rip it all out and start putting in it based on the diagram? Any tips? My wag is bone stock. Runs pretty good for the most part but gets rough idle and cuts out at times. I think that is a fuel supply issue.

[GrandW]

is there a diagram under the hood, next the radiator? that's ideal. Or google, and there's a colored diagram that's pretty close.

[tgreese]

Most of the vacuum line is a standard size, 5/32" ID. It's not very expensive. Here is the diagram:
https://oljeep.com/gw/vac/85/85_FSJ-Vac ... on-360.jpg
from this page: https://oljeep.com/gw/vac/GW_vacuum.html If you have the TSM, it would be useful to refer to that also.

I would print out the diagram and cross off each line with colored pen or similar as I installed it. Even though your original plumbing is not intact, it will give you some hints on what plumbing you need and were it should go. Just make sure you install everything that's on the diagram and all the old hoses have been removed.

[Coreyw454]

Thanks tgreese. That is pretty much my plan. There are two hoses come from behind the block. One is tank vent. Anyone know what the other one is or where it goes to?

[tgreese]

Transfer case vent? I think it goes high on the firewall somewhere and has a plastic cap meant to keep out bugs and splash or dirt.

[Coreyw454]

hmm. Ill have to see if I can track it back to where it goes. Thanks

[Coreyw454]

i have two hard lines running from fuel tank. one from the back and one from the front that go into engine bay at back of engine. one runs to the canister and the other has a U shape and ends. there is nothing on the end of it. is this correct? what should I do with this hard line?

[tgreese]

wagoneertank.png

This is for '82. Probably the same. The TSM will help you.

[Coreyw454]

Thank you

[Dr.Bob]

I *just* finished this job on my '87 J-20, and documented the process; there are three videos showing what I did in this playlist here:

https://www.youtube.com/playlist?list=P ... S3Ovh1iKRg

Part 1- General Overview:

[youtube]https://youtu.be/GReFi9Z59cA[/youtube]

Part 2- Removal of old hoses and components:

[youtube]https://youtu.be/z8Lg-GsbYDk[/youtube]

Part 3- Rebuilding of vacuum spark advance harness (in which I set the record for the number of times someone says "Non-Linear Relay Valve" in a YouTube video...):

[youtube]https://youtu.be/oMXUsV2LzHU[/youtube]

Good luck! It's not a hard job, and it's rewarding when everything is functioning properly.

[HIP]

Dr. Bob,

Great video series! Thank you for taking the time to put it together.

Do you have a finished (color-coded) diagram that you could share? I'm hoping to do this to my new-to-me 1988 Grand Wagoneer, and want to buy all of the hoses before doing the tune up. Do you have any idea on how much of each size tube you had to buy?

Thanks again,

HIP

[HIP]

Dr. Bob,

Thanks for your prompt reply. Your diagrams were a huge help!

HIP

[Hobart]

A good place to source rolls of vacuum and/or fuel hose is Rock Auto and also Amazon, just FYI.
Awesome info above from Dr. Bob!

[Dr.Bob]

Dr. Bob,

Thanks for your prompt reply. Your diagrams were a huge help!

HIP

Ah, glad they helped! It's a big job, but it helps to break it down into the smaller components.

-Bob

[marc]

Have a similar problem with my '84 J-10 straight 6. Intermittently, gets rough when idling in Drive and can stall. If you are fast enough, it will even out in Neutral. Vacuum lines all look OK but there is a snake pit's worth of them, easy to miss a leak. I have gone through a lot of them, sorting them when I put on a new valve cover. It is so intermittent that I am wondering if the vacuum advance might be getting a mechanical hang up periodically? If it were a line leak, I would expect it to be consistent. Can you lubricate the mechanical part of the advance? It is most noticeable when the motor is cold.
Thanks, Marc

[tgreese]

An '84 258 will have the Carter BBD 2V carburetor. This carburetor is notorious for running badly or stalling at idle. Some point to clogged idle tubes - there is an article here http://www.jeeptech.com/engine/carter.html

There is also a stepper motor under computer control that was introduced in '82-ish (?) that can affect your idle quality. Suggest you read the TSM for '84, as there will be pages of discussion and diagnostics for these systems. The MR253 manual for those years is not cheap, but IMO you need it. https://www.bjsoffroad.com/1984-87-Jeep ... _1056.html

There is a stepper motor computer fix that you can find online called the "nutter bypass" (named for the person that invented it). Basically it disables the stepper motor control and gives you a fixed idle mixture, as I undersand it. Search.

[marc]

Thanks for the information. I will cough up for the MR253 manual. What has me bugged about my situation is how intermittent it is.
TheJ-10 might stall once every other day or two or sometimes twice or more in a day, that is why I was wondering about a mechanical cause. I will need to see if it has leaky jets.

Something that might be useful,don't know but I will share it. While the J-10 is the first vehicle that I seriously laid a wrench to in decades, I have spent the last 20 years dealing with 1990's vintage Yamaha 9.9 HP 4-stroke outboards which, like the BBD carb, have very fine idle/slow speed jets in their carbs. In my current boat, an 18 ft. wide catamaran, if I can't run one motor at low speed, the boat becomes unsteerable. What I have done with success any time they start idling roughly is take the 4 gallon portable fuel tank into which I haChevron Techron additive to treat 12 gallons+ of gas and plug the motor into that tank. Run it for thirty minutes to an hour and every time i tried it, the situation has improved. My theory is that varnish accumulates in the carb jets and fuel lines thanks to the alcohol added to the fuel.
Marc

[Dr.Bob]

Marc,

Until you get the manual, you can access the electronic version here (it's the 1982, which comes in three parts):

https://oljeep.com/edge_parts_man.html

[tgreese]

Thanks for pointing to the 1982 TSM Dr. Bob. I expect the TSMs are mostly the same from '82 to '84 except for emissions gear and possibly some wiring for more gadgets. This could trip you up, since emissions gear was evolving over those decades, and considering the whole stepper motor, computer, wiring and plumbing connects intimately with that clean air objective. Just be aware.

[Dr.Bob]

Tim,

the only updates from the M.R. 253 was the 1989 manual; when I ordered the factory manual from Jeep for my 1988 GW (back in 1998), they sent me the M.R. 253, and a bunch of updates.

So, those updates are also available on that site under the "1984 - 1988 MR 253 I.S Bulletins Page" link. Those have updates for every year and running change. You can tell Jeep was just waiting for the FSJ lines to peter out once the XJ Wagoneer and Comanche replaced them, but the FSJ outlasted the XJ Wagoneer (because, I guess, in some areas of life, size does matter).