Smokin the DJet, Chasing vacuum leaks Options

[robkammer]

I'm in the process of the startup of a refresh of our 2.0 in the LE. Case was split, new bearings, cam, etc. Head were refreshed, new valves, guides yada. With 120 miles on the clock I was experiencing some pretty hard bucking. Not surprising to me as it's a new engine. Since the Djet is highly dependent on vacuum signals I decided to buy a smoke tester, very cool device!

I have much to sort yet, but the test showed significant leaking at the throttle body shaft holes in the throttle body. I'm sure these were leaking before we pulled the motor, and the car ran fine. My question for the 'Brain Trust' is: does anyone rebuild these TB's? Or is there anything I can do in my shop to minimize the play in the body?

There are a couple other leaks I found, top of the AAR for example. I can handle that either with sealer or replace it with another that I have refreshed.

Any suggestions will be appreciated.
Robbo

[emerygt350]

There are a couple of guys on here that rebuild TBs. I had Mark do mine. Bartlett 914 is the user name I think. However, vacuum leaks will not cause bucking. Is this occuring all the time or just while at cruise? For example feathering the throttle to stay at 60 or 40.

[robkammer]

Thanks for the reply. The bucking was mild during the first 30 mile break in run. After an oil change and valve adjustment check, the next step was a 100 mile drive. around the 90 mile mark it became pretty harsh on mild or moderate accelleration, then on steady cruise. I made it back to the shop at 96.8 miles. Oil change, valves again, all good.
Going to check dwell and timing again on start up but I wanted to see if I had any vacuum issues as well. I found quite a few. CSV, AAR, and the throttle body.

I'll be back at it again today to address the AAR and test the system again without the throttle body mounted. But I would like to have this one re-bushed or whatever process is used to seal the shaft better than it is. There was a lot of smoke belching from the TPS.

Pretty cool device from Autoline Products, less than $100 and easy to use. Smells like my old Lionel trains!

[Fazasport]

Rob = EmeryGT350 is correct, your problem is the TPS. I had the same exact issue with my '76 914. The circuit board in the TPS is worn. I was lucky enough to find a new TPS but they are almost lmpossible to find new. NLA from Bosch. The good news is that a replaceable circuit board is now available and your TPS can be rebuilt. I believe you canR get one from 914 Rubber or AA.

[emerygt350]

Not one hundred percent sure on the TPS but it is the common reason. You may want to check and see if it is set up correctly first and test to see if it's triggering the injectors correctly (key on engine not running, actuate throttle and listen for injector clicks).

Are you having high idle issues? That is really the only thing that vacuum leaks result in.

How is your timing?