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TBI to PF4….wiring

In your Camaro, was the brake sw (purple wire in my case) the only wire connected to the trans with the vacuum switch in line? With only one wire connected, I don’t understand what locks the tc. Seems like the purpose of the brake sw is to unlock it or its ok to lock The description in the wiring diagram for the other two wires is ecm to brake sw and ecm to gear sw. I would think that the gear sw would signal its in 4th and ok to lock.

It’s painfully obvious I don’t understand what was going on between the original ecm and trans. Thanks for the input so far, I appreciate the help from everyone that has contributed.
 
Mine was sans break switch so vacuum only
 
Finally have it back together. Engine seems to run well, a little grumpy on cold start, just need to bump the throttle a bit or it stalls on the first attempt. With the new engine the k5 feels like it lost 2000lbs. I’m pretty happy with the outcome.
Now, back to the trans… when I had the relay hooked up with the tci vacuum switch as I noted in an earlier post, as soon as it went into 4th, it would lock for a second or two, then unlock for a second and repeat. After disconnecting the solenoid, having only the tci vacuum switch in play, it doesn’t seem to lock at all. The tci vacuum sw is connected to manifold vacuum. Vacuum sits around -18 at idle when warmed up. My thought is that the tci vacuum switch needs adjusted in order to allow the TC to lock. Seems like I could adjust the switch while the engine was idling. I assume the switch is closed due to the -18 vacuum at idle. If I adjust the switch until it opens at idle, and maybe a tic more, I’m thinking that should get me in the ball park to allow it to go into lockup.

Or do I have that backwards?
 
Probably give it about half a turn. You may be able to confirm the switch stays in one position with a vom
 
After a slight adjustment, not quite a half turn. It’s forkin spot on! Shifts great, locks up in OD, speeds up without unlocking immediately, just a bit more throttle will unlock it. :saweet::woot:

Plan on taking it to camp Friday. A 50 mile drive, 20 of that is up hill on I80. Interested to see how the trans temp does with bypassing the radiator cooler. Covered in another thread. Bad news is it’s only gonna be a high of 40 on Friday when I go up.

Motor runs great with the PF4. Idles nice, quick to rev, easy to install. Would have been a lot easier 20 years ago :zombie18:. I couldn’t have done this without the use of a top side creeper, bad back and all. Best $200 I ever spent. Anybody with a truck, jeep or lifted vehicle should have one.

Also, wanted to give a shout out to all the guys on here willing to spend time helping anybody that needs it. :bow:

Doctor @Bent77, thank you sir. You have been particularly helpful with this project, can’t thank you enough.

Happy Thanksgiving.
Safe travels.
 
Da nada my friend! Glad you got it dialed in, and hope you have a good time on Friday!
 
@bdozeraz any updates? I saw the response on the Edelbrock board, get the new ECU yet?
 
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