When traveling down the highway with light pressure on the throttle if you slightly ride the brake at the same time, the rpm jumps 200-400rpm is that the converter unlocking?

So the pcm logic leaves the trans in 4th but unlocks the converter?

 

Yes. Well I know mine will unlock as soon as I tap the brake, then shortly after it will lock again.

 

yes lightly tapping or holding the brake will unlock the converter that is normal

 

It seems like most lock up converters allow a fair amount of slip before they unlock is that correct?

 

Well if PWN is enabled there will be some, However in the lockup release from hitting the brake that would be instant

 

Yes hitting the brake is instant, but if I give it a few light blips of the throttle, the rpm will come up but still stay locked up. When I blip the throttle you can feel the drag of the converter being locked but there is slippage.

 

Thats PWM the partial or controlled apply of the converter (PULSED WIDTH MODULATION)

 

Can you explain that to me? Should I eliminate it? And if so how? It's a 1999

 

Well its just a way he converter is applied and yes i prefer its disabled particulary with small converters, Now while we do this mechanically in our units in you case it would be easiest to make it mostly go away in tuning,
This is done by setting the TCC DUTY CYCLE to 90 min and 100 max this will mostly do away with it ,
It will increase converter clutch life.

 

depends how much throttle you give it. when you're tuning for the lockup, the throttle position (along with speed) is a variable that determines when it unlocks.
the way my lockup is set, i can jab at the throttle and as long as i don't go past approx 25% throttle, it will stay locked.

just as frank is telling you, when you tip in the throttle, pwm allows for slippage. with tcc duty cycle set to 90min and 100max, i have it, but its minimal.

 

wow didn't think so much went into a lock up clutch, I always thought it was on or off and that was it. One last question, if the pcm senses slippage outside of a certain parameter will it apply more pressure to the clutch? So if you installed a different converter would the pcm adjust the pressure required to control slippage?

 

No thats why its a very good idea to eliminate PWM with smaller converters as with less area they will slip more and if the slip becomes excessive the PCM will set po1870 set line to max and disable overdrive and lockup .