jimmyblue

iTrader: (11)

Some people with higher-stall converters seem to
have trouble with chattering or "grinding" and
from what I gather this probably relates to the
misfire detection driven converter unlock function.

Misfire detect keys off the crankshaft sensors and
any abrupt change in crank rotatilnal speed (as I
understand it). Certainly the fast apply of a
lockup clutch would have this effect especially
if the difference between converter slip speed
and locked speed is substantial.

I have felt this once even on my stock converter
but it was just a particular coindicence of lock
apply and feathering the gas pedal. I guess this
becomes a broader region with a higher slip
converter. I have a 3000/2.2 converter waiting
to go on the car.

I have seen some people report that they fixed their
problem by putting a misfire count value to 32768
or some such.

But I would be interested to know if anyone has
explored this further and maybe has an idea of the
lowest value of misfire count that suppresses the
chatter (for them). I would prefer to keep some
of the safety function but ensure that the converter
locks once and only once.

In the end, I'd like to get the proper name of this
parameter and a sensible value for it, that I could
have built into a custom tune for my vehicle. Any
advice would be appreciated.

I think I'd also like to find a way to suppress lock
in 3rd gear altogether (making 3rd - 2nd kickdown
faster and getting back some midband torque
multiplication for street stormin'). I guess this
could perhaps better be done in hardware but if there
is a soft setting I'd like to know about it. The
real ideal would be something that turned off lockup
in "D" but allowed it in both 3rd and 4th when in
"OD".