92LS400 Dainty Little Dither

[Amskeptic]

I love this car.

124,595 miles on it this morning, everything works beautifully but . . . .

a whisper of a delay in torque-converter lock-up. Every single application of accelerator comes with an almost imperceptible "slip" of engine rpm ^ before it goes back down and pulls the car forward.

What tells the torque converter to lock up after it has released during coast-down. TPS? Cable that must be adjusted on throttle assembly?
Colin

 

[gloverman]

The ECU locks up the converter. It calculates lockup based on speed and tps movement mainly. Im running a 91 ECU and it locks up in third and fourth at 60km/h and drops out at 40km/h on decel. Hard acceleration results in lock up dropping out but light acceleration it stays in.

Are you sure its lockup dropping out and not a clutch slip? Whats the oil quality like?

 

[gloverman]

I monitored my lockup signal on a drive one day to check it was getting commanded.

 

[Amskeptic]

The ECU locks up the converter. It calculates lockup based on speed and tps movement mainly. Im running a 91 ECU and it locks up in third and fourth at 60km/h and drops out at 40km/h on decel. Hard acceleration results in lock up dropping out but light acceleration it stays in.

Are you sure its lockup dropping out and not a clutch slip? Whats the oil quality like?

Oil quality is a sweet translucent red.

I know there is not a shift of any sort every time you hit the gas, but does the torque converter lock-up use a clutch pack?

I am getting this weird slight engine-up-back-down hesitation in lower gears too. Now I am confused.
Colin

 

[gloverman]

Converter lockup is solenoid controled which monitors to oil flow to the converter.

I hocked up my oscilloscope to check the command as a start.

IS your engine running as it should? any chance it is due for some maintainence?