Stock converter not locking up.

[phil_jordan]

I'm having the same issue, but too lazy to troubleshoot it. I'm keeping a close eye out so good luck! I agree, that's definitely a step in right direction. Success for sure

 

[mikestertwo]

Update. Thoroughly researched the problem at Brandon Automotive in Spring City PA. Must say Brandon is very knowledgeable. Spent the entire day with the GN on the DYNO. Will put my thoughts together on that and make a separate post. But regarding the lockup, we were able to confirm it was not engaging and by trial and error an "jumping" the appropriate connections we found all the components to be fully functioning but not working when needed. So there is a loose/broken wire somewhere under the dash which, being the end of a long day, I decided to search for on another day. But now I know none of the components are faulty, just a bad wire somewhere. I count that as a success.

Have a silly question....is the computer commanding lockup?

 

[Tom Kelly]

Have a silly question....is the computer commanding lockup?

There are no silly questions. Yes. Every component is functioning correctly. Including the command from the computer.

 

[earlbrown]

Jumping the ALDL won't rule out the pressure switches or ECM output. The jumper bypasses the ECM and pressure switches to show the TCC solenoid and actual clutch is working.

 

[Tom Kelly]

There are no silly questions. Yes. Every component is functioning correctly. Including the command from the computer.

WE first determined that all the correct commands were being generated from ecm and switches. We jumped to see if it was working mechanically.

 

[earlbrown]

If you verified that the ECM and pressure switches are working right, that means ground is getting to the TCC solenoid.

On the positive side is nothing but the brake pedal switch. It should have power going in and out of it when the car is on. When the pedal is depressed one side should go dead.

 

[haywire4130]

Do you have a thermostat in the car? Depending on the chip, i think it needs to see 150 before it will command tcc lockup. If you have a powerlogger (its been a while but im pretty sure) theres a box that gets checked when it is commanding lockup. Just another thing to check

 

[Tom Kelly]

Do you have a thermostat in the car? Depending on the chip, i think it needs to see 150 before it will command tcc lockup. If you have a powerlogger (its been a while but im pretty sure) theres a box that gets checked when it is commanding lockup. Just another thing to check

So much knowledge it’s scary. We verified the command. Just a loose connection somewhere under the dash.

 

[haywire4130]

Naah, i had a gm car once with a stuck open thermostat and the converter would lockup for a couple min then unlock for a couple min and repeat this while on the highway so i investigated further hahaha

 

[GNRick]

If you verified that the ECM and pressure switches are working right, that means ground is getting to the TCC solenoid.

On the positive side is nothing but the brake pedal switch. It should have power going in and out of it when the car is on. When the pedal is depressed one side should go dead.

So like Earl said, ground appears to be getting to the plug on the side of the transmission. Did you check the plug with a test light?

 

[Tom Kelly]

So my final post on this subject. After a long search the problem was found. It was a broken wire in the harness leading to the transmission. After repair a test drive found all working fine. Some characteristics when it IS working:
1. A slight but noticeable "extra" shift (after going into overdrive) This happens at around 48 mph.
2. RPM varies only with speed, not throttle
3. RPM's at 60 mph now at 1,850 down from 2,050. All good
Thanks to all for your support and input. Car can now go to body and paint for the winter.
Happy New Year all!

 

[earlbrown]

Now do the ''barely push the brake pedal to fell it unlock" test.

After feeling it one time, you'll always be able to notice when somethings not right with the TCC.