I have a 1976 2.0 liter car with stock fuel injection. The car was originally sold in CA. I have two hoses connected to my distributor vacuum advance, one on each nipple. Each hose goes from the vacuum advance to a nipple on the throttle body. I recently read where one of these vacuum advance nipples is supposed to be left open to atmosphere on later cars but I don't know which nipple.

Does anyone know for sure which nipple is left open to atmosphere or if the CA cars were unique and should have both nipples connected to the TB?

Thanks!

My 74 2.0 has the "outside" hose left open. Inside hose to TB. Yours should be the same.

If both sides has same vac pressure it would not move the advance. One has to go.

Heres the link to Bowlsby's site that has charts and diagrams. It was a big help to me.
http://bowlsby.net/914/Classic/TechNotebook.htm

Mt 76, previously a California car, 2.0 ,( all 76's were 2.0), has the inside hose open. Car runs great.
Tom

I've been researching this a bunch lately for my 76 rebuild. I believe both should be used. It is my understanding that the outside one goes to the front of the TB and the inside one splits and goes to the back of the TB and EGR.

Both these hoses are different sizes on both the TB and the Vacuum advance Dizzy. That way, you do not get them mixed up. One nipple has vacuum after the butterfly, the other has it before the butterfly. You can barely see the pin holes if you look down the TB and hold it open.

The 75 and 76 throttle body only had one nipple, towards the front, on the throttle body. It connects to the same size nipple on the vacuum advance on the distributor. The other hose just lays under the air cleaner. If you have emissions check in your state, you'll need that hose tucked out of sight under the throttle body. If you have no emissions check just forget it

If that's the case then what would my EGR be hooked up to?

Thanks, everyone. Falconfp2001, your explanation makes the most sense to me. I did not realize the nipples were different diameters until I read your post and went out to the garage and measured them. One nipple is 5 mm OD (this one points to the distributor) and one nipple is 4 mm OD (this one points up at an angle and to the back of the car). I did not look down the TB and observe the pin holes that you mentioned but I will take your word on that. It seems to me that, if the holes are above and below the butterfly, then each of the nipples will experience different vacuum pressures and those differential pressures will move the vacuum advance shaft and properly advance or retard the spark.

Dustin. I can't answer that. Its a california thing. Some one with that knowledge will chime in here I'm sure.

Toadman, You nailed it.

Your close. 3.5 and 5mm. If you need reference diagrams, Pelican has them here http://www.pelicanparts.com/914/technical_...4_20FI_diag.htm

I didn't find anything in the Haynes Manual

I have a Cali. 76 and I can report what my has. On Cali cars 2 port T.B. was re-introduced. The retard is hooked up like always. Advance port on T.B. is connected to EGR and distributor advance is left open to atmosphere. Has short whip hose left loose to keep advance unit dry inside.

see the small black hose from the EGR going to the TB. That is the correct hose setup for the Cali 75/76 setup...I suppose you "could" install a T and hook up the vac adv.