Vacuum lines and Emissions

[JeepJeepster]

Here's the best info I have found on figuring out vacuum and emissions systems.

http://tc.wagoneer.org/search/label/Emissions

Also, at the bottom of that, there is a header called 'Simplification' and tells you how to eliminate some things if you're interested in that.

This is what I used when I simplified my 89 vacuum. Guess I'm different, I do well with picture over reading. Maybe Im an idiot...

Either way, mine works wonderfully now. I removed and capped the CTO in the water neck and removed all of the air tube crap. Capped that port off on the dual CTO. Looks a lot cleaner now. I kept the EGR since I read the carb runs better with it.. Idk if there is any truth to that. I would like to put my wideband O2 in the exhaust sometime to see what the A/F ratio is.

Im all about keeping things like stock but I found out quickly stock is pretty dumb in several instances on the FSJ.

[maybeadinosaur]

This is what I used when I simplified my 89 vacuum. Guess I'm different, I do well with picture over reading. Maybe Im an idiot...

Either way, mine works wonderfully now. I removed and capped the CTO in the water neck and removed all of the air tube crap. Capped that port off on the dual CTO. Looks a lot cleaner now. I kept the EGR since I read the carb runs better with it.. Idk if there is any truth to that. I would like to put my wideband O2 in the exhaust sometime to see what the A/F ratio is.

Im all about keeping things like stock but I found out quickly stock is pretty dumb in several instances on the FSJ.

Was the CTO connected to the upper radiator hose? I can't find another CTO ANYWHERE but i see what looks like a port that was blocked off.

[nograin]

Was the CTO connected to the upper radiator hose? I can't find another CTO ANYWHERE but i see what looks like a port that was blocked off.

The HD CTO screws into the the thermostat housing.

Also, I lost the cap on the large port in the recent photo. Trying to figure out what that is.

You and us too! Seriously. I understand you don't know the parts, but I can't guess which cap, which photo, or whose on first.
As far posting photos. Right click 'view photo' on your imgur photo. Copy the url into the post in between [img] and [/img] or click on the little yellow symbol for images, second from right, bottom row.

As far as diagrams go. If you want it to be stock and correct, the only diagram that can be counted is the one on the sticker in the engine compartment. Fortunately for you, there's one for your engine on Tom Collin's website. Hopefully that way you won't be confused by other configurations. There is only one PCV valve and only one hook up for it on the back of the carb. http://oljeep.com/gw/vac/GW_vacuum.html

Back to your questions.
Its possible that the airpump and air tubes were removed.
You can use either the E or the S port for the distributer's vacuum advance. Without an NLRV, direct is OK. If there is just the spark CTO, then you can have Manifold and ported go that first, then to the distributor (as shown in the 1979 diagram).
Yes you can Tee off the E port. However if the S port is going to the distributor, then your E port will be free to go to the dual cto.
Power valve needs manifold vacuum. Remember, you'll have to hunt for the fitting up there. It will look like the ones in the back. Tee off one of them if you have to. But it is important that no manifold or ported vacuum sources are open to atmosphere. Otherwise that will be what is called a vacuum leak. This is when the air gets into the engine from anyplace other than through the carburator barrels. The controlled leak from the PCV valve is the only exception.

Let me add that if you want the original stuff, a HD CTO can be purchased from a parts store. Nonlinear valve may require some hunting.

[maybeadinosaur]

These were the 2 valves I believe we were looking for. The caps were dry rotted so they've been there for a long while. As previously suggested, I connected "A" on the CTO to the valve at the bottom of the image. The lines running through the TAC TEMP SENS are connected to valve at the top of the image.

If I T the "E" in with the distributor to the E valve, I'll only be left with the open "B" on the CTO. Assuming I'm not totally incompetent and the pump etc was pulled, should I cap it or leave it open?


My GW manual is still in the mail so my research hasn't yielded any results on figuring out what the line is next to the EGR. It's large enough for my pinky to fit inside and was previously capped.


Thanks again everyone. It's much appreciated.

[nograin]

Some definitions will help clarity (and help you solve the puzzle):
Port = Source of any vacuum, usually a barb fitting (my usage, but I think its typical).
Ported Vacuum = Is sourced from a little hole just above the closed throttle postion. So when the throttle is closed (idle) there's no vacuum.
Manifold Vacuum = Vacuum from anywhere under the throttle blade. Created by the pistons pulling air into the cylinders and the air supply being highly restricted relative to the dmand (by the throttles or carb venturis).
Valve = some sort of on/off or conditional switch preventing or allowing flow or vacuum signal through it.

So now I think you can answer your own question. If you connect a line from E Port on the Carb to E on the Dual CTO, what happens at D when the coolant gets hot? Likewise, with A connected to manifold vacuum, what happens at B when the coolant gets hot?

edited: Corrections, sorry I was tired last night.
For PCV valve and connections, see my photo in post#9. Remember the connection into the valley is from behind #8 runner (this different than many other companies that used one of the valve covers to draw from)
Closed PCV Systems explanation and illustration

[nograin]

Grandjeeper,
Do you think it is correct to infer that the Filter is there because there is a small bleed to atmosphere in that side of the CTO?

Nograin's description of the 5-port Dual CTO (coolant temperature override) switch connections is exactly right.

I would just add that the 5-port valve is normally connected to the corresponding lines by a 5-port rubber fitting. Not completely necessary, but nice to have.

You can see the fitting here in this picture someone nicely posted: http://s218.photobucket.com/user/slu...20994.jpg.html

Worth mentioning is the fact that the port marked "C" in your photo is open to atmosphere through a filter, hence the boxed "F" in the diagram.

The filter material is clearly seen in the photo linked above.

[maybeadinosaur]

Some definitions will help clarity (and help you solve the puzzle):
Port = Source of any vacuum, usually a barb fitting (my usage, but I think its typical).
Ported Vacuum = Is sourced from a little hole just above the closed throttle postion. So when the throttle is closed (idle) there's no vacuum.
Manifold Vacuum = Vacuum from anywhere under the throttle blade. Created by the pistons pulling air into the cylinders and the air supply being highly restricted relative to the dmand (by the throttles or carb venturis).
Valve = some sort of on/off or conditional switch preventing or allowing flow or vacuum signal through it.

So now I think you can answer your own question. If you connect a line from E Port on the Carb to E on the Dual CTO, what happens at D when the coolant gets hot? Likewise, with A connected to manifold vacuum, what happens at B when the coolant gets hot?

edited: Corrections, sorry I was tired last night.
Closed PCV Systems explanation and illustration

If I had to guess, I'd say When E is connected, vaccum is supplied by the carb and when coolant gets hot, air/vapor is pulled from the canister & Cleaner/EGR connection? If this is the case, Im thinking I can T into E and be peachy.

In the same way, when A is provided vacuum and the coolant heats, B valve would activate and provide vacuum for the pump? If that's the case, cap A and B because I have no pump, therefore not needed??

I'm slow on this, sorry :P

[nograin]

If I had to guess, I'd say When E is connected, vaccum is supplied by the carb and when coolant gets hot, air/vapor is pulled from the canister & Cleaner/EGR connection? If this is the case, Im thinking I can T into E and be peachy.

Essentially correct. The main clarification being that there is very little air moving through these particular vacuum lines. These vacuum lines are a pneumatic method of signalling and powering simple diaphram switches and 'motors'. Almost as if you had a string to pull. One characteristic of manifld vacuum is that is has a strong relationship with load and throttle. That makes it a handy analog control altering ignition timing in relation to load, as well as adding EGR when it is safe. The EGR valve controls a plunger that blocks or opens a passage. Exhaust gas does not flow into the vacuum line controlling the EGR valve.

In the same way, when A is provided vacuum and the coolant heats, B valve would activate and provide vacuum for the pump? If that's the case, cap A and B because I have no pump, therefore not needed??

You're getting it! Most important, cap the manifold vacuum source. If you've run a line from the vacuum source to A, then capping B is very important. Otherswise there will be a vacuum leak when the dual CTO switches open. If there's no vacuum to A, then its probably not so important to cap A or B. I am a bit curious about the filter and whether there is an intentional bleed to atmosphere. I have a spare engine that had a dual CTO on it, but its down at the machine shop right now. I probably won't be picking it up for a while.

I'm slow on this, sorry :P

You're trying learn and so I'm OK with trying to help.
I think it is tougher to learn on a vehicle with a multiple emmission control systems than if you had started with something simple like a '74 Chevy with a straight 6 (my second car).

[maybeadinosaur]

I capped the mystery valve/port, capped A on the intake and T'd E to E with the carb line.

But now she won't start I thought it was the NSS, which acts up if it get's wet, so I pulled it, cleaned it and put it back on but to no avail. I'll have to try again when it's not cold and rainy. Thank you again for all the help. Once I have it cranked and see how it runs, I'll post updated photos and let everyone know how it works.

[joe]

Don't try to refigure/homebrew your own vacuum routing till you know whats wrong or at least how the vacuum flow and parts all work and interact with each other. Stick with stock routing. That gives you a baseline to diagnose from.
I know this will sound silly and prolly not your problem but it's screwed up more than a couple folks, so no disrespect intended. Note that in the factory vacuum diagrams the CTO's are pictured upside down with the threaded end up. The nipples on the components, some with only 2, some with more are critical regarding hose placements. Can't just put any vac hose on any nipple. Quit trying your own guess-n-by-golly routing plan and hook everything up correctly first and then if no joy keep diagnosing. Don't make things harder than they need be.

[nograin]

I've got this suspicion that the PCV isn't hooked up just based on what you've posted and not posted - and IF so, that would be a massive change to the air supply = no start. When you get a few more photos, especially of the mystery port, we'll know for sure.

Joe, Basically agree with you. But some parts seem to be missing. The '79 diagram is a reasonable fallback to keep it driveable 'til those pieces can be obtained.

[azmtn04]

Thank you all so much for posting this information. Helped me and still is this week figure out this maze of vacuum. It sucks trying to figure it out alone.

[crisd]

update please...

I know this is an old thread but completing the circle of what was done to resolve your issue can help future readers with the same problems (me)!
What turned out to be the problem and what did you do to fix it?
Thanks - Cris

[MysticRob]

I know this is an old thread but completing the circle of what was done to resolve your issue can help future readers with the same problems (me)!
What turned out to be the problem and what did you do to fix it?
Thanks - Cris

Do everyone a big favor and start a new thread so we don't all start reading a 6yr old thread trying to figure out a way to help the guy at the top that doesn't need help, and whose problem may not be the same as yours. We're all happy to help, but starting from scratch with your particular issue can go a long way to getting help faster.

[wiley-moeracing]

Bingo!