78 CJ5 emissions help

I just recently purchased a 78 CJ5 with a 232. I need help identifying which emissions devices were originally installed. The sticker on the grill shows EGR and Air Guard (air injection), but I have a CTO on the rear of the engine that I believe is supposed to be hooked up to the Transmission Spark Control. Does anyone know if the tranmission spark control was standard on the 232? Does anyone have a diagram or pictures of these parts so I can tell what I'm supposed to have?

 

You might want to browse http://oljeep.com/edge_parts_man.html to see if there are any online manuals that can help you out. Otherwise, I'm sure someone will be along soon to offer some advice.

 

There's no CTO associated with the TCS, AFAIK.

There's a '76 TSM (technical service manual, the factory manual) at www.oljeep.com which will show you pictures of the specific devices. Your best reference for these systems is the TSM for 1978. There's no '78 manual online that I know of. Here's one source for the TSM - http://thejeep.com/shop/TECH+MANUAL....html?osCsid=acc432696de16bfdc25c20de28ca21d2 - there are many others.

Emissions devices change from year to year, so the TSM for '78 is your best bet. There will be a table in the manual that says which devices apply to which vehicles. But look at the section in the '76 manual, and that will tell you most of what you're asking.

 

Oh man, I went into this hairball when I first decided that registering 'ol Leanna might be a good thing. First let me tell you that finding new emissions parts for our CJ's is next to impossible. They just don't make alot of that stuff anymore. Once you have the right FSM (see Tim's message above) and know what is needed in the county where you live, you may want to check out some of the used parts places listed at the top of the intermediate forum. PM me if you are looking for something specific and I can scrounge through my records and see if I can help. Good luck!!!

 

All the manuals I have seen show a vacuum switch on the rear of the block with three ports and one of them is connected to the distributor. I have this part on my block with three crimped hoses coming off of it and I assumed this was part of the vacuum advance system. I also have the two port CTO on the front of the block that the EGR connects to.

I have been looking for a TSM for a 78 but all the ones I have found are expensive and I can't afford one right now. I definitely want to get one at some point. I just bought the CJ last Friday (this is my third), and I have it almost down to the frame. If anybody has a 78 TSM they want to trade I have a 74 TSM and a 74 complete factory parts list and the matching illustrated book that goes with it.

 

Yes, you should have two CTOs in the side of the block. The one with three nips is for spark, and the one with two nips is for EGR.

Look here: http://oljeep.com/gw/vac/76/76-FSJ_TCS-System.jpg - the V8 diagram is connected the same as the 6-cylinder, but the parts are in a different location.

The 3-port CTO switches the distributor advance vacuum between manifold vacuum when the engine is cold, to ported vacuum when the engine is warm. Ported vacuum comes from the base of the carburetor and is blocked off by the throttle plate at idle. Thus manifold and ported vacuum are different at idle, but not otherwise. Jeep calls the ported vacuum port the "spark port" in some places.

The TCS solenoid cuts off the line from the spark port to the distributor when the switch on the transmission is open (closed? whichever - as long as it's connected right.) The TCS has a switch on the transmission, and a solenoid on the top of the engine that's controlled by the switch. Everything else is just plumbing.

The factroy manuals will be your best source. I don't think you're going to get a lot more insight from the '78 manual than you could get from a careful reading of the '76 manual. The systems are the same, though there could be some differences re what systems are present on which vehicles and engines.

Contrary to what Jason wrote, I don't think the parts situation is so awful for these systems. Certainly the CTOs are available - look on RockAuto under "switches" - they are often called "ported vacuum switch" in the non-Jeep parts listings. If you are serious about making the CTOs work, you need to test them. They are vacuum switches - which ports are opened and closed at what temperatures is described in the manual. Use a short piece of hose and blow through one port and check that the other is closed. Dunk them in hot water and see if the ports switch. A Mity-Vac is helpful for this.

Another place where the Mity-Vac helps is testing the EGR valve. Pull the valve off and clean it thoroughly with a wire brush, removing all carbon from the pintle. Test that the pintle stays open under vacuum - the usual problem with these is that they have a hole in the vacuum diaphragm. The EGR valves are available too.

Hopefully that will get you started. Just look at the manuals you have and read them carefully (ignoring the Haynes or Chiltons manual, should you have one of those), tracing out all the systems that are there. Simple!

 

Thanks Tim,

I looked at the tranmission and I don't see a TCS switch, just the back up light switch, also the manual you pointed me too says that TCS was only used on CJs in California for 76 (don't know about 78) if there is no TCS switch on the transmission what do I use that CTO for? It's possible the PO could have removed that when he tore out all the other emissions stuff. Where should I look for the TCS switch on the tranmission?

 

I haven't seen a T-150 TCS switch, but I expect it's in the same place as on an earlier T-15. It should be on the opposite corner of the transmission cover from the back-up lights switch. Both these switches are activated by the shift rails, and the shift rails move opposite the position of the shift knob - ie reverse moves the right rail back, and third moves the left rail forward.. where it pushes on the switch.

Without the TCS, you connect the vacuum ports the same as with, except there's no TCS solenoid in the circuit. The CTO will switch from manifold vacuum to ported vacuum when the engine warms up. Look at the '72 manual here http://trailforge.com/TSM/Section_04A.pdf - there's more discussion of the CTO and TCS, which may help you. Port 1 to manifold vacuum, port 2 to ported vacuum, and port D to the distributor.

 

I will look and see if there is a switch on the transmission or not tomorrow. At least now I know how to correctly hook up that CTO. Do you know where I can get a replacement TCS solenoid if I need one?

 

I expect you can find them via a WTB (want to buy) ad here. Most people would not bother to put them back if either were missing - the Jeep will run fine without them. At worst, your engine will be making slightly higher emissions than it might. Are you planning to move to a strict enforcement area, like California or Phoenix/Tucson? Even there, I doubt they would notice if you passed the tailpipe test.

 

Where I live, we don't have any emissions testing. I just like to have everything as original as possible. I'm just obsessive compulsive about little things like that.

 

I'm hoping to find a TCS vacuum solenoid myself someday.

So far I've not had any luck.

I'm sure there are any number of vac solenoids that would work. I just need to know if it does in fact pass vacuum when it is energized.
(Or de-energized?)

 

cancelled