vac, emmission help, 76 304

I bought this 1976 CJ5 new in 1975. It's made the rounds and I got it back. Has not run in several years. Replaced the Motorcraft carb and fired it up. Emmission components have been removed. What needs to be hooked up or plugged. Vac on choke and dist. PCV no valve? What's the thing by the driver side firewall that is in intake manifold?

Does anyone have a diagram showing the engine and identifying components, vac lines etc?

 

So in Texas they require smog inspection for a transfer or is it an every year thing? My V8 has a egr valve behind the carb and the pcv valve is back there too but it is much smaller. I also have a smog/air pump and probably had a tube to warm the air to the air filter.

 

No emmission checks in my area. I've connected vac. for the distributor and choke. I've connected a tube from back of the carb to the crankcase vent, no valve. I plugged all vac. ports I could find. Any idea what the device with a tube is on the back driver side by the firewall installed in the manifold?

I'm planning on a test drive today.

Any suggestions?

 

I think your going to need a pcv valve on the intake manifold end of the large hose coming off the carb. The only other thing back there and its on the drivers side of the intake manifold is the egr valve. At least i think thats what it is. Looks like 2 bolts hold it on. Is yours missing?

 

You need a PCV valve, minimum. You also need a clean air intake to the crankcase. Usually that's from the air filter, but you can buy little stand-alone filters at Autozone.

I'd also keep the charcoal canister, since it properly vents your fuel tank.

Just because they don't check doesn't mean it's legal to remove the systems - it just means the law is not currently enforced. AFAIK it's not legal to remove any emissions systems under federal law, but enforcement is up to the states.

The tube in the manifold may be your choke stove. Pic?

 

My goal is to get the Jeep running and use it on the ranch while I restore it. I'm trying to figure out what is supposed to be there, whats there and what's essential for interim use.

Found a partial diagram.

PCV valve and hose. Will replace.
EGR I think this is the component mounted on the driver side rear of intake manifold? Looks like it connects to a temp switch next to the oil fill on the intake and then to vac source on carb?
ECS Fuel evap control has been disconnected. Connects to air cleaner and Tank vent line?
AI Air injection? no clue at this point?
Filter for crankcase vent in air cleaner?
Spark Control System? No clue. Sol Valve? Coolant temp switch? Trans switch?

Checking battery and alternator today to see whay it won't stay charged.

Any help is appreciated.

 

AI is air injection - the most troublesome of all.

The PCV pulls air through the crankcase and into the manifold via the PCV connection on the back of the carb. The air inlet is basically part of the PCV system - you need clean air going into the crankcase, where it is mixed with the crankcase fumes and drawn out via the PCV valve and hose.

I know it may seem like a lot of money, but a factory manual will really help. There will be a table in the manual of which systems were used on what models of Jeeps. Each system will have a section. There's no overall diagram AFAIK, but you can put things together if you go through the sections.

EGR is exhaust gas recirculation. The valve on the manifold feeds exhaust gas into the fuel-air mixture at highway speeds and reduces NOx by lowering the combustion temperature. If you disconnect it, you'll run slightly lean because the mixture is set for dilution with exhaust gas. Check the plugs to assess the mixture.

Spark control gives you full manifold vacuum to the distributor when the engine is cold. There's a CTO (coolant temperature override switch) with 3 ports for it. Helps driveability when the engine is cold.

I'll check on the vapor recovery (charcoal canister) later - I expect you'll need the stock air cleaner and the canister if all the tubing to the aft of the car is still in place.

 

Your canister should have 3 connections - from the fuel tank, to the air cleaner snorkle (to purge the charcoal), and to the carb bowl vent. You need the stock air cleaner.

A 49-states '77 304 CJ-7 has Air Guard (AI), catalytic convertor, EGR (115 degree CTO), FTVC (fuel tank vapor control), PCV, TAC (thermostatic air cleaner, vacuum type). Manual trans will have a carb dashpot, auto has a solenoid. Surprisingly, no spark control CTO. Should be pretty close to '76.

 

I understand the fuel canister.
I understand the EGR connections but need a coolant temp override switch. Mine is broken. Any suggestions for parts?
I understand the TAC thermostatic air cleaner
I understand the PCV but need a new hose.
The rebuild carb I bought has an electric choke vs the temp activated. The carb has a tube with some kind of control and pulls a vac when running. Pass side. I have this plugged. Any idea where it should connect.
I have the vac from the distributor connected to an intake vac port. Should there be any other vac advance controlls?

I want to replace the oil and temp sending units. Good parts source?

I have a Haynes manual and a Rebuilders manual, but they are not a lot of help. Is there a good detailed manual available anywhere?

Thanks for all the help.

 

In order, these carbs are thermoelectric so they use both heated air and electricity to warm up the choke cover spring and open the choke. You'll have a wire connection that's hot when the ignition is on, and a tube that connects to the choke stove in the manifold.

The choke stove is next to the exhaust crossover in the intake manifold and heats up as the engine runs. IIRC it has two small tubes coming out of it and has a plate that bolts into the manifold. In the carb, there's an internal passage to vacuum from the choke cover, which draws heated air up the pipe from the choke stove to the choke cover. The air is supplied from a connection on the carb at the air horn (?? I think - it's been a while since I've worked on a V8).

You can replace your choke with a manual choke if you want; there's a kit you can use from the parts store.

If it's the same as a '77, you have the distributor advance connected to ported vacuum (distributor vacuum) all the time.

From a local parts store? They should be easy to get from Standard http://www.smpcorp.com/web_app/catalog/publiccatalog.asp or Napa http://www.napaonline.com

The factory manual is the best. http://thejeep.com/shop/HOT+SELLERS....html?osCsid=5848f5094198763aa17fe340c35060c2 There are a few places you can get them on the net, and they sometimes come up on ebay. The parts manual is good too, but you have to be a real Jeep nut to want one of those.

 

Got the heat activated choke working. I don't plan on using the electric element, only the one heated by exhaust gas.

What is the down side other than NOx emmissions to using the jeep before I get all the parts for the EGR system in and installed?

 

Sounds like we have the same problem. I just bought a 76 with a 304. All the vacuum lines have been removed and the egr valve is gone. The parts man said that there are 3 different egr valves that were used, and he needs the OEM number, I don't know how to get the OEM # without the old valve. Also there is a valve on the back of the manifold, next to where the egr valve should be. i don,t know what it is

 

Here is what I would do. I would get a factory service manual and one by one get all the systems back in order. I think this way you will experience the best drivabiltiy and engine reliability. Besides it can be a fun challenge and you said you wanted to restore it right??

Their may be a 1 or 2 systems that you can exclude, the AIR pump for one I thing, that can get expensive and I am on the fence on how much it help compared to PIA factor.

Main thing is get the vacuum system working correctly and the carb will breath correctly = good running motor on the cold and warm days = more fun. Around 75-76 the car companies started designing engines to run with this stuff intact rather then just bolting on emmisions stuff like they had done in previous years. Also the truck will worth more if someone looks under the hood and sees all original systems intact.

Best of luck and make sure you post any questions.

 

Somebody with the factory parts manual can likely give you a Jeep PN for your EGR valve (Jim?). Certainly 49-states will be different from CA, and there may be a change based on the VIN.

 

There are several different EGR PN’s for a 304. You will need the stamped PN on the EGR, and then you will be able to purchase a new one at most any auto parts store.

 

Thanks for the input. I still don,t know what the valve is on the back of the manifold (drivers side) next to where the egr valve should be. I'm going to take a ride today, I passed a farm that has 3 CJ's sitting out behind the barn, hopefully 1 of them has an intact 304. I am also working on getting a service manual.

Thanks again
Dave

 

Dave, post up a picture of the valve you are asking about. There's a pocket at the back of the manifold that's usually called the 'choke stove.' It sits next to the exhaust crossover in the intake, and provides heated air for the thermoelectric choke. It could also be a decel valve, TCS solenoid, CTO, or maybe something else.

I have a '77 manual, and it calls for air injection, cat, EGR, vapor recovery, PCV, TAC, and carb dashpot for a 49-states 304 CJ-5. A '77 is probably close to a '76, but no guarantees. You should have an EGR CTO too, but I thought those were at the front of the V8s, not the back.

 

I think what I am looking at is called the Exhaust Back pressure Sensor. I did find some halfway decent diagrams at oljeep.com and jedi.com. I would post pictures but when it comes to gadgets, I'm lost in the 60's

Thanks Guys
Dave

 

The EGR# on my '76 304 is #17050471. If it is the exhaust back pressure sensor, it will have a small metal tube that comes off a 3/4"-1" spacer between the intake manifold and the bottom of the EGR valve (the EGR vavle sits on top of this spacer). The EGR valve vacuum connects to this pressure sensor, then runs from the pressure sensor over to the CTO port. Here is a link to the 1976 service manual, it's PDF's: http://oljeep.com/edge_76_tsm.html

 

My research (Factory Manual + web sites) indicates the following EGR informaiton:

The specs are as follows:
Backpressure types
vendor 7043589 vacuum required open start 1.8-2.2, open max 5.0
vendor 17050471 vacuum required open start 1.8-2.2, open max 5.5
vendor 17050472 vacuum required open start 1.8-2.2, open max 5.0

Vacuum types
vendor 7040176 vacuum required open start 2.8-3.2, open max 7.0
vendor 7030881 vacuum required open start 2.9-3.2, open max 9.0

In addition to the above specs, some EGR have a restrictor plate that is calibrated for the type of engine, location (Calif, etc.). The restrictor reduces the diameter of the hole that exhaust gases pass through.

I've settled on 7030881 with #9 restrictor for my 360 since I don't have the backpressure equipment. I will probably go with AdvanceAuto part EBR915, the brand is BWD, their website has some cross references in the catalog. http://www.bwdbrand.com/Online%20%20Catalogs-eCatalog/Content.aspx