GregN

Background: 84 Berlinetta LG4, just got done doing some work adjusting the carb and replacing the temperature sender. Car ran fine afterward until I got on the highway. Then it will lock, unlock, lock, unlock the TC. It can't decide what to do. The TV cable was already adjusted per Leo's instructions but I did it again anyway. No change. Is there something in/around the carb that got misadjusted or disconnected? Is it just coincidence?

Thanks,


(edit) Oh yeah, the fluid is correct and cherry red, normal smell. Also it for some reason does NOT seem to be affected by throttle position. The tranny is also trying to lock up in third gear. Is that supposed to happen?

Jay 727

Could be a problem with the vacuum hose for the tcc (thing) I forgot what it's called. It's a black rectangular box about 1" by 3" on the passenger side firewall. It has a vacuum hose and wire connector going to it.
This box controls torque converter lockup, when it loses vacuum it unlocks the tcc as when accelerating.
When it gets vacuum it locks the tcc, as when cruising.

GregN

I think I found the box (on the pass. side firewall). It has the number 591 4062 stamped on it and it has a two wire connector going to it. There is a nipple at the bottom which appears to accept a vacuum hose. However there is no hose. What does this vacuum line go to?

Attached is the pic of the vacuum line diagram, but I don't see this component on there.

grumpygreaseape

ck. brake pedal switch-when driving, place foot down lightly on brake pedal while keeping other foot on gas-does the lock-unlock-lock behavior stop?

Jay 727

It's the vac sensor in the diagram, thats the only thing other than tv cable adjustment that I can think would cause a transmission problem after carb work. The hose should go to full manifold vacuum.

GregN

So if I were to adjust the TV cable one click either in or out, how would it affect the tranny? Does it affect TC lockup at all?

Oh, and Jay, the black rectangular box is not a box which controls TC lockup. It is the BAP sensor, or barometric air pressure. The one on the other (drivers) side is the manifold air pressure. They look identical. They *may* eventually have some effect on TC lockup after the ECM decides what to do with the information, but I'm not positive about that.

transfixleo

The coolant sensor plays a large role in TCC control. Did you use OEM? Did you make sure that it is full of coolant after completing the work?

GregN

Thank you Leo and everyone else for your input. Even though I did not get a direct answer I was able to talk myself through the problem.

When you replace the air horn after removal, what is the biggest pain in the @ss that you run across? The TPS! I guess I messed with it enough that after 18 years it decided to give up. I tested it this evening and it was reading .5-ish throttle closed, but part throttle it was all over the place. Just off idle where you'd probably cruise the most it was sending WOT signals to the ECM. A little more and it was normal. About 3/4 throttle it was WOT again and then progressive all the way to actual WOT.

So hopefully this one will sit in the archives and help someone else out. Replace the TPS and the TC will love you for it.

Later guys,

Kingtal0n

Heh, you may have just solved my problem, Now if I only knew what a TPS was and where to find one, (help!) I will begin to love my TC i think...

GregN

The check is in the Tech articles. Or just do a search on Yahoo for "CC Q-Jet". That's how I found it.

Kingtal0n

I have throttle body injection, do i still have a TPS ?Im assuming so since the computer knows when i floor it...

GregN

Sorry I'm not familiar with the TBI cars. I'm sure you've got a TPS since TBI is more advanced than the CC Q-jet engine. My best guess would be that it is attached to either the throttle linkage or hinge on the throttle body. Hint: It'll have several wires going to it.

Jza

It's on the passenger side of the TBI and has three wires going to it. They are basically a rheostat just like the dash illumination ****, which tends to develop "dead" spots (every Camaro I've had had dead spots on the dash switch where you'd dim the dash down and at certain spots it would go completely off as you pass over them), so imagine what an old TPS is going through.

Sorry to get away from the original question. My convertable's tranny does that too, but I think it's because I used an incorrect pressure switch when I rebuilt it.