Hello everyone. I am sure this has been discussed multiple times already. I just want to make sure the vacuum hoses to the distributor are connected properly. My 74 1.8L has a dual port throttle body, but one side (side facing towards the firewall) is plugged off with what looks like a factory rubber plug. The side of the vacuum advance unit facing the passenger side of the car has a vacuum hose going to a vacuum t-fitting to manifold vacuum. The other vacuum fitting on the vacuum advance unit is going to the throttle body, which if I am correct is ported vacuum off idle throttle. Vehicle production date 4/74. Stock FI. Where I used to work, I had access to the cloth European vacuum hose. So I slowly replaced sections over time with new hose in the same locations where the old hose was.

mine is a jan 74.

what is the T fitting you are describing also hooked up to besides the distributor retard hose and the hose into the intake plenum?

thats the vacuum retard side of the advance/retard if its facing the passenger side.

what you are describing is a bit different to mine.
but i have both ports connected on the throttle body.

curious about the hook up to the t fitting as that t fitting, in about that position, on mine has nothing to do with the dist advance retard, its a t fitting taking the fuel pressure regulator vacuum hose and the decel valve vacuum hose to the intake plenum.

Follow my thread on a similar subject and check out the diagrams. Hope this helps.

http://www.914world.com/bbs2/index.php?sho...=355743&hl=

It seems that I have two vacuum t-fittings. Someone before my time during my father's ownership (still current owner from new) seems to have added another vacuum T inline with the line that goes to the intake plenum (manifold vacuum) which a factory vacuum t-fitting is present and connected. Is the port that I show plugged off with a vacuum plug also manifold vacuum? If so I will delete the second t-fitting and reconnect the retard side (red dashed line) to the front port off the throttle body (where it seems it's supposed to go from factory). The advance side (blue dashed line) is attached to ported vacuum rear facing port off the throttle body currently.

the blue marked hose line matches mine and matches correct hose layout diagrams.
straight connection from vacuum advance side of dist to port on throttle body (rear port).

----

as to the vacuum retard line (if still original will be green color) thats where there is information saying there was two different layouts.
seems some cars never used the vacuum retard hose connection to the other port (front side of throttle body) but the hose was there, just tucked under the distributor and left open. it was put there even though disconnected to help prevent dirt and debris entering the vacuum retard port on the distributor. i've never come across info that says when and which cars this was applied to. some say its more random than a specific date in production. i believe its the same distributor in either case.

i guess it makes sense as these are the first cars (along with the VW 412) to have L jet ever. so no surprise that VW and bosch might have been tweaking and adjusting the system as they went for the first 6 months or year of production.

there is some other stuff i have read about having both vacuum advance and retard and it being to do with emission strategies. others with their heads right around that level of detail know way more and can explain it better. i never even realised there were variations on the theme until i came to replace hoses on mine 2 years ago and found diagrams that did not agree with each other, or agree with my car (which was trustworthly original). early stone age emissions systems are not something you tend to encounter on australian cars. we got slightly more evolved systems by the time it all got introduced here.

Unfortunately all my vacuum hoses are now black cloth hose. My car is also a California emissions certified vehicle for the 1974MY (model year). I will continue my research. I will most likely end up removing the added vacuum T that was added inline with the line that tees off to the fuel pressure regulator and the decel valve, and running a vacuum line to the front port of the throttle body from the retard side of the vacuum advance unit.

@L-Jet914

i like your avatar name mate.
the vacuum hose stuff can give you a headache.

could be wrong but i think the 74 1.8s were all states compliant including california.

mine has a engine bay sticker above near the fuse box that says california compliant as well as all the rest of the blah blah. it was delivered new to washington dc - state of maryland then went to live a quiet life in the midwest after the owners left town. maybe they worked for gerald ford administration?

Oh trust me I know. At least our 914s aren't as bad as mid 80's early 90's Japanese cars that went vacuum hose crazy. Or early US domestic vehicles 80's. Those cars really give me a headache following all those lines.

@L-Jet914

i had a thought on the two vacuum port and found a cross sectional diagram.
i added it to the other thread linked above as i thought it best to keep info in one spot.

someone might have modded yours knowingly to cure emissions compliant behaviour.
the diagram made me think of a quirk mine does when its cold. i have described it in the other thread.