Torque Converter Lock-Ups

[David A. Cooley]

At 01:50 PM 12/23/98 -0500, you wrote:
>
>-----Original Message-----
>From: kv at us.ibm.com <kv at us.ibm.com>
>To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>Subject: Re: Torque Converter Lock-Ups
>
>There are no iron clad strategies, for TCC.  What some one says is usually
>about their experience.  In the gm calibrations, there is sometimes a
>mandatory lock up speed, reguardless of TPS, but (and off hand I can't think
>of an exception) there
>is usually a TPS disable in the gm calibrations, at less than that speed.
>  Most all if not every gm uses a brake switch as a fail safe so that the
>TCC
>won't engage, at a stop, and launch a car into an intersection.  The are
>other reasons, but the lawsuits of a TCC failure, and not having a brake
>switch cut out would scare even gm, IMHO
>Bruce

All the GM TCC circuits I have seen from 84 up to 95 have a mechanical
pressure switch in the trans that opens if it's below 2nd gear and closes
for 2nd, 3rd and OD.  The switch is usually in the TCC line to the PCM.
Of the several cal's I have seen between 84 and 95, the TCC has a fixed
lock-up speed in each gear, and a fixed unlock speed, but also a delta TPS
unlock. (Unlocks if you goose the gas!).  The later cals have a TCC PW that
modulates the PW going to the lockup solenoid depending on TPS, LV8 etc and
it allows a certain percentage of TCC slip.  These still have a fixed
lockup and unlock MPH.
Later,
Dave


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           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
     Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
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