OK another vacuum hose thread.

Just got my car running again after 4 months down, and during this time I got in on the 123 distributor GB.

My engine is a 2056 with the 2.0 FI and two port throttle body. I have the dizzy set on position #1 which is used for the vacuum advance. and this is the port I have hooked up. (green arrow - A ) and I have blocked off port B

Click to view attachment

It did run okay but not real enthusiastic, which makes me think I hooked up the wrong vac port on the throttle body. Is port B the advance port?

Previously it had the stock dizzy with both vacuum lines hooked up.

right now it is just static timed at 5 deg btdc using the led built into the 123 dizzy.

what benefits are there to using the vacuum port for advance VS using the retard port and the corresponding setting in the dizzy?

Fortunately I can access the dip switch in the dizzy without removing it. (I think)

Hopefully Beat Navy will wade in on this subject since I think our engines are set up similar.

Use the advance (B in your photo), port the one closest to the dizzy, cap the retard port (A) in your photo,the one toward the rear of the car.
Use switch position #1 for a '73 setup or #2 for a'74.
I have the'74 I'm using #B, set my timing to 26 degrees BTC and hot days I use a fuel additive to up the octane number, I have the retard port only, caped it off and nothing connected to the dizzy.

The other Rob will chime in, but I think that is correct.

You have it backwards. No sense using the retard port since there is only one vac port on the dizzy.

I have mine set up for advance on the TB as well with no issues.

Make sure you have the static timing set first and that all other issues are resolved.

So my experience is a bit different. I ended up going to curve "B" and using the retard port on the throttle body as the connection to the dizzy. I plugged the advance port (I'm actually using a TB now that already has the advance port blocked off). In your picture, A is retard and B is advance. My setup (MPS, ECU, etc.) most closely matches a '74.

I love these dizzies now, but I was surprised about the amount of 'trial and error' it took to get things working optimally. This is probably mostly due to the fact that my original throttle body may not have been year correct, and the dizzy I was replacing was definitely not. So selecting the correct advance curve was a challenge.

I then timed it like stock - 27 degrees at 3500 RPM with the hose plugged. It's running great.

So, the other thing that threw me off is that this dizzy seems to be very sensitive to idle mixture and idle speed. I was having trouble getting idle to settle down below 1500, and I kept thinking maybe I was too far advanced. But when I would back off of 27 degrees, I wasn't getting the performance I knew it was capable of. Then I started playing with the idle mixture and I was surprised how much idle speed was reacting to changes with the ECU idle mixture knob. Leaning the mixture out one or two clicks on the knob made a significant difference, and now I've got a nice stable idle at ~1000. I did not see this behavior nearly as much as on my previous setup.

When the weather gets a little warmer (and drier ) I'd consider "playing" with a different advance curve and putting my old throttle body (with advance port) back on. But right now I'm pretty happy with how it's running

Shameless plug......


Ed posted my car on his website...now there is a 914 there.


I found the same thing to be true that the idle setting is way more sensitive but found the idle stability once set, to be the best it have ever been which is something for D-jet.

Idle fluctuations have a lot to do with alternator load, charge the battery to full before hunting down idle problems.

Nice pic!! Here it is: http://cdn8.bigcommerce.com/s-hn1to57xds/p...pg?t=1518443690


Good, I'm glad I'm not going crazy. Yup, once you get it there it's pretty solid!

Thanks again for putting the GB together, Rob.

OK so I corrected the lines and now the advance port on the throttle body connected to the dizzy and the dip switch set to #1 for advance.

Now this begs the question, since I have two ports on the throttle body and with the stock 009 dizzy there were two vacuum ports. Now I can only have one, which would be the best to have connected?? The advance port and setting #1 on the 123 dizzy OR use the retard port and setting #A.

I really don't know for sure where these vacuum signals come in or cease to have any effect.

Guess I will try it with the advance connected first and see how it runs. But remain open to suggestions.

I keep hearing that you should NEVER cap a port on the dizzy. Can someone please confirm this confusion yet again? McMark?

You need advance for performance. Retard is mostly for bringing the idle down, no? I don't see any important need for retard, but performance demands advance.

I think he means A (in my picture) the retard port on the throttle body, not the port on the dizzy

Ah, yes. A port on the TB that's not being used should be capped.

My suggestion is to do what Beat Navy (Rob) did. He has the same motor as you. As I understand it he used the retard port and changed it to a different curve in his post

However he did use another setting as I read it. I'd just follow the directions to the tee in the manual and check it with an adjustable timing light.

I still have the original 1.7 in my car. I used the suggested setting in the manual capped the retard port at the TB and used the advance port at the TB to the dizzy and checked the timing with a light. Of course I set the static timing first and plugged the two ports and the TB before that.

You have the exact set up I am going to...a 73 TB with a 2056.