Not a trany tuner. . . Yet!

[Spindoctor]

Howdie All,
Most of the trans adjustments I have made so far are of the firm-up and smooth over variety with good outcomes.
Today I have a 2001 Camaro we did a supercharged 6.6 build we did a few months back. Car runs well at about 650hp.
What the customer reports (& I have verified) is that when under medium heavy (Not WOT) load in D (Not OD) the 2-3 shift flairs badly.
I have lowered the shift time to .25 and raised the pressure by 20% in that load range for the 2-3 shift. No noticeable improvement. The shift occurs at 3500rpm and 55mph. I could raise that rpm point but I don't think it would help with the flair.
The trans did get hardware upgrades and a 'shift kit' along with a higher stall converter while we did the motor work.

1) At what point do I stop punching the keyboard and call it a hardware issue?

2) Which PIDs should I put together as a data log for tranys file?

I knew there would come a day when I would have to start paying closer attention to those trans settings.

[joecar]

Post some logs (include RPM, VSS, TP, MAF, MAP, GEAR, TCCMODE, LASTSHIFT, TFMPRS, TRQENG...)

One possibility: if airmass derived from VE and/or MAF is too low, then PCM does two things incorrectly:

1. it calculates/looksup a much lower in-gear base pressure (slips constantly a small amount... monitor TFT);

2. calculates TRQENG too low, and consequently looksup a much lower shift pressure (slips during the shift);


See if the shift pressure tables have flat/zero spots.


Or maybe it is blowing thru the converter...!?

Or maybe the 2nd servo is not releasing all the way (by 3th clutch fluid pressure pushing it back out)...
Or maybe 3rd clutch fluid pressure is not applying the 3/4 clutch all the way (leak in circuit)...
But at WOT there is sufficient pressure to push both of those...

$0.02...

[Spindoctor]

Here is the latest log with flairing 2-3.
Note that the flair begins at time code 09:58:26.183 where at the next frame
Current gear changes to 3.
I have included the tune file also. I can not seem to get 2nd gear to reach
90 psi before the shift. It hits 90 the instant 3rd is commanded. I have commanded my Base Pressure 2-3 shift up to 650 starting at 380 delivered torque. However as the log shows it only reaches 75psi. and.4 amps. I may be missing another adjustment someware that wont let me get it down to .2 amps. Now since this is before the shift it may not matter.
Let me know what you think.

[joecar]

Tim,

I think there may be a problem with the transmission's pressure regulator and/or the PCS solenoid (which regulates "Torque Signal" pressure which 'assists' the pressure regulator)...

I can't see anything in the tune file that would cause that.

If you have a transmission pressure gauge (0-300 psi), connect it to the pressure tap on the LHS of the case (just above the shift lever), and view the gauge while driving... if pressure doesn't spike up (to ~220 psi on WOT upshift, maybe to 175+ psi on medium PT upshift) then the pressure regulator is malfunctioning.

If pressure is ok/high, then there may be other physical malfunctions (2nd servo not releasing quick enough, 3/4 clutch not applying quick enough).

I'm wondering if the torque converter is "blowing thru"... but typically it would do this at high torque/load, not at PT.

What is the atf condition, and what is the history of the trans...?

Log TFT also.

[joecar]

See: showpost.php?p=39472&postcount=4 (http://forum.efilive.com/showpost.php?p=39472&postcount=4)

In this diagram:
- follow the yellow hydraulic from 1c -> 1a/3a (pressure regulator),
- look at 2c (2nd servo slow in releasing). <<edit: on 2nd thought, it might not be this>>

[Spindoctor]

We have a local trans re builder who happens to be an 'F' Body freak.
He did not realize that we are EFI Live capable so it looks like we may be able to do final set ups for him in the future.

I will let you know what the outcome of this trans is in a couple of weeks.

I hope to be able to return the favor with informed replies of my own down the road.

Great job as always!

[joecar]

Cool...:cheers: