The TCC solenoid (small black box on pass. side of firewall) has a two-wire connector going to it and a nipple on the bottom that appears to accept a vacuum hose. I don't have a vacuum hose. Where is this hose supposed to go to? Right now my TC seems to lock and unlock whenever it feels like it.

Thanks,

 

Whoa, we're way off base here.

What you're looking at is the barametric absolute pressure sensor. It provides that info to the ECM so it can adjust other parameters as you go. It is the same exact sensor as the manifold absolute pressure sensor, which senses the manifold "vacuum", we call it, via a hose - thus the nipple. But, the BAP is supposed to have a foam block over the nipple (mine doesn't either).

Your TCC problem lies elsewhere. That signal comes from the ECM based on gear you're in and vehicle speed (couple of other things, but vacuum isn't one of them, directly).

 

Okay. Thanks. I was misinformed by someone on the Transmission board that it was the TCC solenoid controller. Where's the TCC soleniod? On the tranny? I guess the ECM takes the vacuum signal (based on load), the throttle position, and rpm and tells the TCC when to lock up or not. Is there another sensor somewhere that would confuse the computer as to when to lock up the TC?

Oh and sorry this is turning into a transmission post on the Tech board. Not only was I not getting much info over there, I guess I got bad info.

 

The TCC solenoid is in the tranny.

The controller is the ECM.

It is possible a goofy signal from one of the sensors is making the ECM go into spasms - MAP, TPS, VSS, RPM.

Also, the brake light switch is two-part - one part for the brake light, one for the power to the TCC. If the switch isn't adjusted quite right, you may be giving the TCC a "bouncy" power supply.

 

I didn't mess with the brake switch. I'll take a look around the engine compartment and see if there's anything I missed as far as sensors go.

You know I've been searching the archives all day and I've seen several of the same symptoms come up but no one got a true answer to the problem. Just a bunch of talk about a "patch" by using the switch to manually lock the TC. I also found some mention of the Air Idle Bleed. Now there's something I may have messed with having took the carb apart. But I don't understand how that could possibly affect the TC lockup.

This one's going to drive me nuts.....

 

my 89 RS would lock and unlock randomly while driving down the road. My fix was to wire a manual lockup switch (pins 1 and ... 6) on the little ECM Connector (they use to check engine codes) and when its starts doing its thing i insert a paper clip between those pins and it stays locked up for good till i hit the brake or pull the pin.

 

I found the problem and fixed it. It was the TPS. It was fine at idle position but jumped around on the way up between 0v and 5v. Sometimes it was telling the ECM that it was WOT, and other times it was fine. At part throttle cruise it was on the edge of being WOT and normal. This confused the ECM and kept sending the TC signals to lock and unlock. Thanks to everyone for their help and letting me talk myself through this problem.

 

Yup, that was in the list. Congratulations on a successful diagnosis before replacing unnecessary parts!

 

Ignore the following list of words. I'm posting this because I had such a hard time finding an answer through the search engine. Hopefully it'll be easier on the next guy...

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