lock-up torque convertor

[brandnu6]

Hello. Torque Convertor does not lock up at highway speeds, above 50 M.P.H. in 4th gear. Someone suggested "jumping out" ALDL ports "A" and "F." after doing so, it worked fine. By the way, I changed "brake switch" at pedal. Brand new "ACDelco." The one with purple wire. There is another one also. TCC solenoid was changed-out maybe 5 or 6 years ago. I know there are two "pressure switches" in transmission for 3rd&4th gear, screwed to "valve body." For now, I will use jumper and take it easy. Over the winter, when car is in storage. I will pull pan down and trace back the wiring. Unless someone thinks it in the ECM? Let me know your thoughts, Thanks very much...

 

[1986 Buick GX1]

I believe the brake light switch is separate from the TCC kick out switch.
It seems the TCC kick out switch has hoses/ vacuum switch.
My converter didn’t lock up from the day picked it up from the dealership (ordered new) until I inadvertently lifted the brake pedal.
I readjusted the vac switch and it’s worked ever since.

 

[salvageV6]

If it locks via the ALDL port it's the same wire the ECM uses to lock it up so it's not inside the transmission.
If it locks up via a jumper it's not the brake switch since that provides the +12 to the solenoid and it works via the ALDL jumper.
Make sure it UNLOCKS when you have the jumper in place by stepping on the brake pedal when driving locked up.
Could be in a splice of the tan wire or a bad ECM or a chip that never commands lockup?

 

[brandnu6]

If it locks via the ALDL port it's the same wire the ECM uses to lock it up so it's not inside the transmission.
If it locks up via a jumper it's not the brake switch since that provides the +12 to the solenoid and it works via the ALDL jumper.
Make sure it UNLOCKS when you have the jumper in place by stepping on the brake pedal when driving locked up.
Could be in a splice of the tan wire or a bad ECM or a chip that never commands lockup?

Thanks Man. Sounds like GOOD advice. I will try the brake to see if it unlocks. What I did not mention was the fact that, it did work "before" trans. was "rebuilt!" From what I've read, if TCC solenoid is reverse wired [polarity] it will fry Diode inside of it. Also, as I mentioned in original post, there are two "pressure switches" for 3rd and 4th gear lockup. If wire not hooked up, then there will be a problem as well. I will trace out the wiring [ALDL] Tan/Wht. wire which is a "ground" Same as the other port at ALDL between TCC Solenoid, and ECM ground. Thanks again...

 

[pacecarta]

you grounded aldl and it worked so the brake switch is providing 12v (pin A) and the ground (pin D) is complete at least to the aldl connector

stock ecm/chip ?

the ecm uses the 3rd 4th switches in trans to engage ground with the chip programming
connect a scan tool and verify MPH (vss) is reading above 47mph and 3rd or 4th transmission switches show
LU needs >47mph and either 3rd or 4th gear switch to be open

besides lockup the 3rd gear switch also allows safer timing drop and boost drop in the stock chip,
if they dont open the chip will run higher timing and boost in higher load gears. turbotweak chips can lower timing based on mph

 

[1986 Buick GX1]

I believe the brake light switch is separate from the TCC kick out switch.
It seems the TCC kick out switch has hoses/ vacuum switch.
My converter didn’t lock up from the day picked it up from the dealership (ordered new) until I inadvertently lifted the brake pedal.
I readjusted the vac switch and it’s worked ever since.

My apologies, I was thinking of the cruise control kick out being a vac switch.
The TCC kick out is off the brake switch.
Carry on.

 

[brandnu6]

Thanks guys for great information. Pacecarta, thank you for your advice and diagram. Stock ECM, with Eric's chip. 93 octane, no Meth! I will drive car around for now. I did make a few upgrades, Eric burnt another chip [more fuel] to accommodate Champion heads, Precision stretch I.C., and Gen ll 5558 BB turbo. I removed ECM, unplugged both connectors, and started checking wires for "continuity/power." I'll figure it out. I've had this car for 10 years now and chased down lots of issues. Patience and good information from people who know what they are talking about is how I do it. Thanks again...