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View Full Version : RPM drop with TCC lockup?



DrX
April 6th, 2006, 02:52 PM
Does the 1500 RPM drop starting here look like it could be due to TCC lockup? I don't see any other reason for it as TP is still at 100% and there was no upshift yet. Lockup VSS is set to 144.8km/hr at WOT in 3rd gear.

joecar
April 6th, 2006, 06:51 PM
Check your TCC throttle release tables, they would be at 100%, and if so, the TCC should not be locked while TP is 100%.

The RPM drop is due to the 2-3 shift; the shift seems a little delayed (compare RPM drop with GEAR rise)...

but the GEAR pid going 2->3 is when the PCM has decided that a shift is needed, and then the PCM commands solenoids after some delay (log the shift delay pid), and then the RPM drops in response (log the last shift time pid).

joecar
April 7th, 2006, 01:53 AM
TP is still at 100% and there was no upshift yet. There is a 2-3 upshift a little to the left of the cursor.

Edit: and the RPM drop starts happening at the cursor.

DrX
April 7th, 2006, 01:47 PM
There is a 2-3 upshift a little to the left of the cursor.

Edit: and the RPM drop starts happening at the cursor.

Makes sense if there is a delay. Shift times varied in todays logs from .1 to .7 sec. Shift delay varies also. Shift times are all set to 0 in the tune due to the shift kit. And pressures are set to GM factory values.

TCC throttle release tables were all at 100%, but logged TP isn't always quite 100% at WOT. So I changed B0105 to 99%.