vacuum

numberonegaffer · Post by **numberonegaffer** » Sun Apr 23, 2017 2:01 pm

I know that vacuum has been discussed ad nauseam but this is a very specific question so...

I have an 86 wagoneer. There is a "valve" , I'll call it valve A, on the intake next to the base of the oil filler tube. It has three nipples. there is a rubber piece that fits onto it and distributes three vac lines to...

Screen Shot 2017-04-23 at 4.49.21 PM.png

There is another "valve" , I'll call valve B, on the thermostat housing that also has three nipples.
One nipple from valve a is connected to one nipple on valve b. Two nipples on valve a go nowhere.

Screen Shot 2017-04-23 at 4.50.40 PM.png

One nipple on valve b goes to parts unknown in one direction and is open on the other. One nipple is open

Screen Shot 2017-04-23 at 4.52.04 PM.png

Can anyone identify these "valves" and tell me thier importance and if they would affect my engine performance. It is very rough at idle.

tedlovesjeeps71 · Post by **tedlovesjeeps71** » Sun Apr 23, 2017 2:07 pm

Pics don't open for me man.
Valve B is the CTO (coolant temp override). I think the other one, A, is also part of that system. Has something magical to do with the emissions garbage. Maybe REDONE or Gabe will chime in to help.

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tedlovesjeeps71 · Post by **tedlovesjeeps71** » Sun Apr 23, 2017 2:08 pm

Oops, pics work now!

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tedlovesjeeps71 · Post by **tedlovesjeeps71** » Sun Apr 23, 2017 2:09 pm

And yes, they effect how things run. Especially if the broken ones are still attached to a vacuum port.

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Tatsadasayago · Post by **Tatsadasayago** » Sun Apr 23, 2017 2:22 pm

Here's a diagram of your emissions system.
The CTOs control Spark, EGR, A.I.R. and the Evaporative system.

tedlovesjeeps71 · Post by **tedlovesjeeps71** » Sun Apr 23, 2017 2:58 pm

So if some of them, such as the one on the thermostat housing is removed, that effects the timing??
Hmm... Wonder if that's part of my issue??

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numberonegaffer · Post by **numberonegaffer** » Sun Apr 23, 2017 5:07 pm

Holy cow, I'll try to make sense of that diagram. Looks like maybe my valve A would be the spark CTO and my valve B would be the non-lnr vlv, Whatever those are. And yeah, looks like a lot of vacuum leakage!!!

memo43 · Post by **memo43** » Sun Apr 23, 2017 8:49 pm

Sorry to side trac but, if I delete all those connections
An just go from the dizzy to the carb port,
Keep the pcv valve an brake booster valve, will I benefit any.
I swapped to an hei unit running a eddy 1406 on my rig PO deleted all the smog, emissions stuff, and I don't get the sniffer test
Again sorry for side tracking

440sixpack · Post by **440sixpack** » Mon Apr 24, 2017 9:31 am

Yes, just make sure you delete it all not just parts of it.

Most of the time for non smogger engines you're best off to run manifold vacuum on your vac advance like in the old days rather than the ported vacuum of later years. either way check your total timing with and without the vac advance hooked up with a dial back light once you're done.

Tatsadasayago · Post by **Tatsadasayago** » Mon Apr 24, 2017 11:12 am

I think the thermostat CTO was a California Emissions specific deal but I can't remember what it's function was.

FWIW: If you're running a carb, leaving the spark CTO circuit intact would actually be helpful since it blocks vacuum to the distributor until the coolant temp reaches 165 degrees. This applies whether you're running ported or manifold vacuum to the dizzy.

Charles Kline · Post by **Charles Kline** » Tue Apr 25, 2017 10:09 am

numberonegaffer wrote:Holy cow, I'll try to make sense of that diagram.

Check out this PDF i made with each system in its own layer that you can hide or unhide. It makes it easier to get a grip on whats what with the AIR injection tubes and control hidden.

http://www.fsjnetwork.com/forum/viewtop ... 10&t=11638

-Charles

numberonegaffer · Post by **numberonegaffer** » Sun May 07, 2017 12:08 pm

Thanks for the color coded diagram. Makes things a little easier!! Going out to get started on it now. BTW, I just bought a kit of vac hoses and connectors from amazon for $24. One stop shop hopefully with different sizes and various lengths of hose.

numberonegaffer · Post by **numberonegaffer** » Fri May 12, 2017 2:27 pm

okay, I've been struggling to match up as many of these lines as I can but I can't complete the process. I can't find the spark cto. This vehicle has an Edelbrock intake and Holley 4 barrel. I assume the Spark cto mounts into the intake? Also, I have a lot more vacuum connections on the carb than the diagram indicates for the original.

The Spark cto is required for vac advance isn't it? What the hell do I do about that?

memo43 · Post by **memo43** » Fri May 12, 2017 2:55 pm

Post a picture of your current set up, I'm not using the cto the previous owner replaced the stock intake with an edelbrock an pretty much either plugged everything or deleted everything
My current set up is

EGR= delete
1406 for card
After market HEI
All emissions stuff removed (no emissions testing req)

Only vac I have is the brake booster
Vac for dizzy connected at carb (running ported vac)

TeaBag · Post by **TeaBag** » Wed May 17, 2017 5:46 pm

The CTO is a Coolant Temp override valve. Valve B-The one on the thermostat housing is used to control spark advance. To my knowledge its on all the later model vehicles as smog equipment. When the engine is cold it supplies ported Vacuum off the carb to limit spark advance. When the engine warms up, it allows the spark advance to be controlled by manifold vac.

The theory was to not advance timing (retard) when the engine was cold and this would raise cylinder temps and promote faster engine warmup which would be better for idle emissions. Interestingly, retarding the timing also raises the emissions, so I'm not sure how effective it actually is at reducing overall emissions. I suspect the engineers new it was a bogus thing but was required to have it by government regulations.

Cant tell from your pic what value C is controlling. That is an aftermarket intake so you will just have to trace the lines and see where they go.

The three hole plug you show went to the dual CTO on the rear of the manifold and controlled the EGR valve and vapor canister purging.

Yes- the CTO on the thermostat housing controls the spark advance (refer to the first Paragraph). If you don't have to work about smog inspections, you can eliminate it and just run vacuum straight from the manifold to the distributor.

tedlovesjeeps71 · Post by **tedlovesjeeps71** » Wed May 17, 2017 6:14 pm

So there's 3 CTOs, correct? One on the t-stat housing. One to the passenger side of that, still at the front of the manifold. And then the bigger one at the back of the manifold near the EGR. Can all of them be removed and plugged? Is any of it useful?? Any that MUST be there??

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TeaBag · Post by **TeaBag** » Wed May 17, 2017 6:33 pm

I have a 91 and there are only 2 CTOs-just like the diagram above. One on the T-state housing and one on the rear of the intake manifold.

You can eliminate the T-stat CTO.

The one on the rear depends on what you still have installed. Do you have an EGR Valve? Do you have a vapor canister? If yes, you will want to keep that one to control when the canister purges and the EGR valve.

I have TBI fuel injection installed, so my spark advance is controlled by the computer. I do not use the T-stat CTO. I do use the Dual CTO on the rear to control the canister purge. I have eliminated the EGR valve.

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