I have my friend's '79 here, needing to "make run". It is a Montana car, in Calif now 12 years, during which it has logged 50 miles. The underhood vac diagram shows timing specs only for Automatic and this is a factory 4 speed. most forums don't lead to a good diagram, just nonsense comments trying to seem superior, or asking "where are you?". I don't need that. there is an EGR, no A.I.R. pump, missing A/C compressor. large manifold fitting behind carb not shown on any labels/diagrams I can find. Has heat riser, vacuum advance through a temperature fitting, heat riser through another temp fitting, and one more for canister vacuum. is the vacuum tank fed through the big mani vacuum fitting? Chilton's doesn't have any vac. diagrams, youtubes and google images no help, lots of threads read, no help. maybe I can inspire someone with a complete original car to make a youtube of it for me and everybody else. Make it good, I've seen so many bad ones. Pity me-I'm resealing the intake which is a lot heavier when I'm 62 than when I was 25.



Thanks, Andy

 

Just plug it off.

 

if you don't know what this is for, why post? "Just plug it off"?! Someone here must know more than that (nothing). I should have said more clearly in my original post-no trolls please.

 

It's probably part of the emissions system,don't get butt hurt you said you want to make it run so **** off.
Plugging it off will stop the vacuum leak,if it were mine I'd chitcan all the smog crap.

 

all it has on it smog-wise is an EGR valve and catalytic converter, and a few thermoswitches. California requires bi-annual smog checks and inspections to make sure you don't bypass or eliminate all the "emission crap". So it's not just to get it running, but to make it run right. A foreign concept to those in 49 other states, and Calif is very harsh on its rules and VERY expensive to register cars, but compliance is mandatory if you want to drive a car with a valid license plate. Not butt hurt, just frustrated with guys who chime in but know nothing about the subject, which is: factory set up per actual vacuum diagram reference to keep it legal. Not some Ohio hillbilly trying to outrun the law

 

I have worked on these cars at the dealership but only a few California cars. There are two types of vacuum, Manifold and ported. Ported needs to be filtered and it can do anything and not affect how the car runs. Manifold vacuum can be used to move vacuum motors but it must have a sealed working environment. Any air entering the manifold vacuum will cause more emission issues then the parts it was supposed to be controlling could ever help. Step one, NO vacuum leaks. Ported vacuum is from the throttle plates up and is vacuum with no fuel mixture in it. Manifold is already mixed with fuel. Anything that changes that vacuum (like a leak) changes the fuel mixture.

Sorry if that is too basic for you but I needed a starting point.

I believe you need an original factory manual. There may even be a separate insert covering the Cali emissions. I doubt anyone others then a Concord restorer specializing in early second gens is going to know this stuff off the top of their heads.

After saying that I believe there was a elbow on that vacuum port, It was a common failure point. Depending on the year it "Y"ed to the Vacuum canister for the heating system and to the thermo switch on the thermostat housing.

Also when it comes to inspection you can make any car pass emission from the tail pipes just with carb and spark adjustment. If the inspection station is going to fail you because something is not hooked up like factory then they should tell you or be able to provide you with the diagram of what they are wanting to see. It has been my experience that most inspection mechanics are very weak on older car and if it appears right its good. To truly inspect and verify an emission would take 4 to 5 hours. You can put a metal ball in a vacuum line to block it and tell a mechanic to find it with tests. It could take him days. (I am having flash backs to school.)

Not sure how much this helps you with your thermo switch but you can use a gage to see if they are cold open or cold closed or if they are working at all. Exhaust cross over should be cold open. You can go over this one system at a time but since this is a Cali car I am not sure of anything. They did some funny things with timing and EGR valves.

I completely understand your frustration with people telling you to get rid of all that stuff. Heck you can find GM bulletins that say after 24 months you can just disconnect some of the emissions items. On many cars GM says the entire air injection system is just there for engine brake in and can be removed after 500 miles.

 

This is what I've heard for years and have known people who did just that albeit not in California.
I've always lived in rural areas in Oregon and Washington where I didn't have to go through a DEQ station like folks in the cities do .


I was a little caught off guard as I would have thought a car that old would be exempt,I think up here anything older than 20 years is exempt.
Leave it to California to put the screws to car people.

 

Well I don't know how one would expect anyone not in or from California to know the rules and difference in cars there,damn near a foreign country compared to other states.

 

I am from PA and in West Chester we had emission testing on the tail pipe back in the 80's. You could play with the metering rods and timing even the heat range of the plug to get it to past smog. After that the car would run like crap and be back next week to have it all undone. We also had a max cost of like $400 to get it to pass after that just put a sticker on it. Back then there was no connection if you were fixing a customer complaint and the yearly emission test. Only the dealers had to be compliant with all repairs. Luckly for me I never worked in a dealership that was in a smog tested area.

I do remember some shaking and hesitation issues with fuel injected cars that we had to wait till the car was a minimum amount of months from the build date before we could change the prom to a fuel mapping that worked better. This was a federal regulation from the DOT.

I watch a show call Roadkill on motor trend. There is a guy on there named David Freiburger, he buys a lot of project cars, he lives in Cali and made the comment on the show that he has predefined all his car searches to be pre 1975 to avoid all the emission hassles. From reading GM manuals I know Cali emission requirements reached all the way back to the mid 60's but policing those cars would have very little value vs the training every inspection mechanic would have. Last time I was in my dealer I do not think any of the techs were over 30 years old. I am sure most have never rebuilt a carb nor would they have any clue about the emission systems from the 70's or even the 80's.

 

Back in the early 80's my sister had a 1967 Mercury Cougar with the 289 V8 and it had a smog pump on it being originally a California car.
Sis lived on the Oregon coast and her hubby at the time didn't know much about cars so I spent a weekend there and tuned it up for her since it was running poorly.
First thing I did was junk the smog pump and plug off everything related to it after junking all the hoses etc.
That was my first experience with a car that old having smog crap on it.