4l60E / T42 TC lockup problems

Hi ,
after some first timer troubles I am into the game. I just returned from some test runs. In the past I noticed a strange TC clutch behaviour. . When applied I still could hear a constant change in rpm. No I have it in the first log. I recorded the TIS, TOS , and the TCCslippage. When the TC is applied there is still a 30 - 60rpm slippage like a sine wave. That's the sound I heard...

I read somewhere that in the 2007 applications the TC isn't locked ful, there is always some slippage... but what I recorded looks a little strange for me.. I think need some help.... ;-)

THX

Harald

Harald,

Use the CALC.TR pid from the attached calc_pids.txt file
(in folder My Documents/EFILive/V7.5/User Configuration, save/rename your old calc_pids.txt file and replace it with new one)...

you will see that in 4th gear that the ratio TIS:TOS is 0.696 +/-0.001 (which is +/-0.14%)...

This is very small amount of slip, and the fact that TCCMODE says "Slew" indicates it may be normal (tho I am not certain)...

Log TCCDC to see what duty cycle the PCM is commanding.

(sanity check: 0.696 indicates you have a 4L60E, correct...?)

thx for the hint. I will do some new logs tomorrow.
And yes it's a 4L60 E.
What is strange for me is the sine wave the slippage is going up and down and you can feel this when in 4th gear at low rpm's

Harald

Harald,

Can you feel it only at low RPM, or at higher RPM also...?

What does engine RPM look like compared to TIS and TCCSLIP...?

>>> oh, you know what I just realized... :doh2::doh2:
The 4L60E does not have a TIS sensor... the PCM/TCM computes TIS from TOS (VSS sensor)... so TIS:TOS will always be correct... I am sorry, silly me (slap me now...:bangin:)...


Collect some more logs... include VSS, RPM, TP, TCCDC, TCCMODE, TCCSLIP, GEAR, MFTOTAL (misfires) [or the equivalent pids for your ECM/TCM], and a few others.

Joe

Here is what I got (seen also in the GENIV thread..) from the E38 default metric PID file. I added short and log term fuel trims.
That humm from the TCC could only be felt in 4th at low rpms under load. I think it is that sine wave in the TCCslip pid.

A silly question why isn't the TCC locked 100% when applied?
I try to find some mpg to get an improvement over the current 13,7mpg at a long drive with a very carful right foot max speed 70mls/h

Harald

I'll be in OCCA in april, but sadly I won't have the Tahoe with me.. ;-))

Harald, is that the right log file...(I don't see TCC pids)...?

In 4th gear at low rpm, the PCM may be feathering the TCC for any number of reasons.

OrCo in So.Cal...?....Cool...:D...Which city...?

We will fly to LA and visit a friend of mine in La Habra. Then there will be a trip to Vegas and the rest is still open...

That log is the E38default pid selection plus the long /short term fuel trims.

The one with the TCCslip was the first one...I will do more logs today.
By the way I run into trouble when logging, I have to choose ECM or TCM first when connecting to the vehicle , I guess I cannot log data from both controllers in one log file/PID selection ??

Harald

Create/log a calc pid for RPM - TIS and compare this with TCCSLIP.

Oh, ECM or TCM, not both... let me ask Paul.

Enjoy your visit, we'll see how our schedules go...:cheers:

If you use black box logging (i.e. standalone logging) on FlashScan V2 you can log ECM and TCM simultaneously.

The PC based scan tool cannot do that yet.

Regards
Paul