Problems with Torque Converter Lockup

[2000Transam]

I have searched but I cannot seem to find a definite answer. I just installed a 3600 stall converter and a fully rebuilt transmission into my 2000 Trans Am. The trans shifts great, has a Transgo HD2 kit, my builder eliminated the PWM in the valve body. The issue I am having is the torque converter lockup. It will shift fine on the 1-2, 2,3, and the 3-4 but when the converter locks up it locks then unlocks then locks etc etc etc. How do I fix this in my tuning?

Thanks!

[joecar]

Are you getting any misfire counts...?

[2000Transam]

I see I posted this in the wrong section, I should have posted in the tuning section. The person that tuned my car changed all the misfire tables to 32767.

[joecar]

Ok, I moved the thread to the Tuning section.

[joecar]

Ok, your tuner has disabled misfires.

Can you tell if the PCM is unlocking the TCC...? The pids TSTATE09 and TSTATE10 show the reasons why the PCM unlocks the TCC.

[2000Transam]

The PCM does unlock it due to brake on, downshift, and upshift. I had 4 frames that it was unlocking it due to both upshift and downshift. When the surging/lock and unlock occurs the pcm is not commanding anything. I'm not sure if its locking and unlocking or if its just surging. Only in 4th during lockup (i do not have it locking up in 3rd). I do not see it commanding TCC fully locked thought under TSTATE10?

[joecar]

To see if it's locked look at these pids:
- TCCMODE,
- TCCDC,
- TSTATE00 bit "TCC Enable Solenoid"

when the PCM commands the TCC locked: TCCDC will be above 50%, TCC Enable Solenoid is on (1), and TCCMODE says "Locked";
the TCC is fully locked when TCCDC is above 90% (no slipping), but TSTATE10 may not necessarily show this.

[joecar]

Do you have any logs showing VSS, RPM, MAF, MAP, ECT, IAT, GEAR, TCCDC, TCCMODE, TSTATE00, 09, 10.

If the PCM is not commanding the TCC unlocked, then the surge you feel may be either:
- the TCC may be slipping, see below (the stall converter is physically smaller, so the TCC friction area is smaller);
- the transmission may be slipping (the 3/4 clutch most likely).

Try doing this:
- set the TCC min DC to 90% (D2903),
- make sure the max DC is 97% or above (D2904);
- increase the speed at which TCC locks/unlocks (D1003, D1006).

[2000Transam]

Well, pcm is commanding it to lock. The solenoid is commanded "ON", the TCC mode is locked. TCCSlip does log 400-500 rpm slip when throttle is applied and converter is locked. I have the pwm minimum set to 99 and max set to 100%. I even decreased D3802 force motor current positive -5% across the board to see if increased line pressure would help with clutch hold. Does this mean my converter clutch just isn't holding the power? Is there anything I can do tuning wise to make it lock and hold locked?

[2000Transam]

I also have a pending code p0748....not sure if my "experimenting" caused this or if its an issue with the solenoid?

[joecar]

Sounds like the TCC may be slipping. That DTC may be due to this.

[2000Transam]

Anything that could remedy that with tuning or is it simply a converter issue? I was thinking of trying to go for a drive and manually command the converter to lock and see how it responds to throttle input.

[joecar]

Let us know how that goes.