[63T-Bolt]

Have a 1979 Buick Centry II station wagon with a 301 Pontiac V8.

I rebuilt the engine and lost my information on what vacum lines go where. I have some of the lines taken care of but I really would like to verify everything. I have the factory service manual and it doesnt do squat for me........

[engineer]

the factory service manual is excellent. look under section 6E emission control systems and all the vacuum diagrams are there. For the pontiac factory manual 1978 is the key with the 1979 and 1980 supplements to the 1978. Listed by VIN code for each particular engine. Don't know how buick's are.

[mguerci]

Is there a specific set of connections you are having difficulty with? What type of carb do you have?

[63T-Bolt]

The ones I am having trouble with now are as follows

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

Ported vacum switch on Pass. side head, two port gray, I found it on the autozone site but it doesnt really say which line leads to where clearly.


Air cleaner assembly, there are TWO vacum switches on the air cleaner. One on the back side and one that i know is the temp sensor for the vacum operated inlet valve, the other I have no clue where it goes (possibly to the rear vacum break for the carb??)


It is a 2bbl carb as well........


I need to figure this out because I want to fire this thing up sunday so I can start to break it in and enjoy all the hard work I have put into it.

[CraigGT37]

63T-Bolt,
I have the 78 factory Buick manual and 79.The 79 I cant get till next week(in storage)so I scanned the 78 vac diagrams they go into more detail than the autozone diagrams. Hopefully they help.
Craig

[63T-Bolt]

If I could get the lower portion of the first pic blown up so I can see it clearly that would help some i think. I cant seem to find what they call the sensor on the back of my air cleaner..... it doesnt seem to name it

[CraigGT37]

63T-Bolt,
I have them saved on my comp. I can send them to you via email if you want.send me a PM with your email address if you want them.
The vac sensor on the air cleaner that has 1 port is called a "modulator" in the book,it shows it going to the choke tube as an inlet for the air.The 2 port is called a"thermac sensor" and it does go to the thermac motor on the snorkel of the air cleaner.
Craig

[63T-Bolt]

Originally Posted by CraigGT37

63T-Bolt,
I have them saved on my comp. I can send them to you via email if you want.send me a PM with your email address if you want them.
The vac sensor on the air cleaner that has 1 port is called a "modulator" in the book,it shows it going to the choke tube as an inlet for the air.The 2 port is called a"thermac sensor" and it does go to the thermac motor on the snorkel of the air cleaner.
Craig

Sending PM.

There is one more sensor on the air cleaner. The thermac is located inside the element area, this other sensor is outside of it on the side of the air cleaner, has two vacum ports. I "believe" this goes to the carb choke break, I just cant find any information in my book on it at all. Also the book I have doesnt show any vacum diagrams like you posted above. Just a broad version of a haynes IMO, not sure if GM does it like ford, but the "chassis" manual is a broad overview, and they have more in depth books covering specific area's, I have the chassis service manual.

[engineer]

all should be in the 1978 factory service manual, not chassis.

[LPete]

Originally Posted by 63T-Bolt

this other sensor is outside of it on the side of the air cleaner, has two vacum ports. I "believe" this goes to the carb choke break, I just cant find any information in my book on it at all.

That's exactly right, the two port vacuum switch controls the secondary (rear) choke pulloff. The idea is that after the intake air warms up a bit the secondary pulloff will open the choke a little farther than the primary pulloff opens it, and the engine will still run fine because of the warmer air. The goal is to get the mixture as lean as the engine can tolerate to control emissions while the engine is warming up.

[63T-Bolt]

Sorry for the late response, but I did finally get the car up and running shortly after this posting.


I did get most everything workinging emissions wise on the wagon and it runs ok, just trying to get all the tiny details worked out on it right now. The damn carb is giving me fits from time to time, and I think the hei module is giving up on me. Not bad considering both are the original units with over 100k miles on them!!!

Sorry for the dirty air cleaner, I just had got done putting some water on it and didnt get a chance to clean it up. Once it gets warm all new a/c hoses and other components go on it to get it all truely 100% back together.

Plans are for later on this year to get it repainted back to stock along with the woodgrain. I wanted it all stock because I have a plan for it..........