Hello

Any ideas how to get shift signal from 722.3 to aftermarket ecu. Plan to turbo my sedan too but for the sake of gearbox would be good some spark cut for gearshifts.
722.6 with ofgear controller would be way to go but ill try to maintain some budget.

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MB 300CE Turbo '88
MB 300E '86

Can your ECU perform any logic functions?

First, get an apply chart for your transmission. You would need to install pressure switches on each friction element hydraulic line then have the ECU decide when each shift occurs.

You might be able to do this with a pile of relays though a small PLC would be better as you can easily program in delays / reconfigure operation. Have a look at the " Click " series of PLC from Automation Direct / KOYO. These are very low cost , software is free and ladder logic is easy to learn.

As an example with the shifter in drive.

1st Element A
2nd Element B
3rd Element A and B
4 th Element A and C

Up shifting
Car at rest, shifter place in drive , pressure switch on element A turns on = no action

Car moving, shifter on drive , pressure switch on element B turns on = fuel cut signal.

Car moving, shifter on drive , pressure switch on element A and B turn on = fuel cut signal.

Car moving, shifter on drive , pressure switch on element A and C turn on = fuel cut signal.


Down shifting at closed or light throttle, no action.

Down shifting at high throttle / kick down, fuel cut.

Not sure how the pressure responded through a shift. But it may be a way to monitor when its shifting. Only experimenting will tell.

Personally I would go with a 722.6.

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John Roncallo

I know, 722.6 would be the right choice.
Problably i dont have any issues without limiting power on 722.3 but some bangs would be nice.
Ill get some spare gearbox and try to learn on that. Havent been in automatic world so some knowledge wouldnt hurt.
Problably try like 92SL320 recomended, pressure switch and plc.

__________________
MB 300CE Turbo '88
MB 300E '86