vacuum line from distributor?

[BrokeMyCar]

Hi folks,

I think I discovered why I've been starting rough, and barely passed smog despite all my other tune ups: a vacuum line was nibbled off at the back of the engine! Can anyone help guide me on where a new one should connect to? I'm working somewhat blind back there so pictures/diagrams would be very helpful, but even a description or the connecting part I should look up would be very appreciated. It's the lower line going from the distributor behind the left of the engine.

Thank you -

Babak

[AlKidd]

Your distributor has two. The one on the vacuum module (left side) mounts to the front of the throttle body, below the throttle plate. On my 83 it was between the two larger ports. It needs vacuum on acceleration. The other on the right side mounts to the rear of the throttle body, above the throttle plate. Its is for deceleration. Factory has them as different color hoses. Red & Blue. Pics of my dizzy, and front and rear TB.

[BrokeMyCar]

Thanks so much AIKidd! The picture of the connection of the red hose to the TB in particular will be so helpful as I’m fumbling around back there.

As an aside, I’ve always wondered about whether I’ve been doing my timing correctly. When you set the timing do you disconnect both of the hoses? Do you also plug the ports on the distributor or just the hoses?

Babak

[AlKidd]

I believe you only need to disconnect the vacuum side of the dizzy when setting timing. You could always check what happens with the light when you disconnect the decel side. My understanding is the decel side was added for emission purposes. I suspect the reason you were running rough is with that vac line broken you have a pretty good vac leak. How was acceleration? Guessing pretty weak with only mechanical advance working.

Originally Posted by BrokeMyCar

Thanks so much AIKidd! The picture of the connection of the red hose to the TB in particular will be so helpful as I’m fumbling around back there.

As an aside, I’ve always wondered about whether I’ve been doing my timing correctly. When you set the timing do you disconnect both of the hoses? Do you also plug the ports on the distributor or just the hoses?

Babak

[AndrewCologne]

Also here this gives you a nice overview of the vacuum connections:

https://nineelevenheaven-wordpress-com.translate.goog/unterdruckanschlusse-an-der-k-jetronic-fur-den-us-sc/?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=de
(Translated via Google)

[ahh911]

[QUOTE=AlKidd;11563403I suspect the reason you were running rough is with that vac line broken you have a pretty good vac leak.


At throttle body, retard vacuum is pin sized hole, nut much air getting through there, won't make a noticeable difference plugged or unplugged from unregulated air perspective. To prove to yourself, remove the blue hose from dist, reset idle rpm, then plug and unplug the hose to the throttle body and then drive around as well just for good measure.

Phil

[BrokeMyCar]

Thanks all. I replaced the hose - there’s no way I would have been able to do it by feel without your image AIKidd, thank you. I didn’t have time to drive it around but did start it. The first time it turned over a lot and stumbled before getting going. A short while later I started it again and it fired up quickly, unfortunately I didn’t have a chance to let it warm up, reset idle, drive it aroundetc… I’m going to drive it around some this week and if I still have doubts my next query will likely be into the fuel injectors. Thanks!

Babak

Ps very cool German translated site Andrew