MembersPage/GergelyLezsak/StageThree (2005-07-25 22:31:21)

Stage 3 - Control misc. devices


Suggestions...

As for driving BMW E30 series (inline 6 engine) tachometer, one needs to find out how original ECU (ie. Motronic) drives tachometer.

Unfortunately I dont know driving signal waveform/type and hence currently can't help, reason because we did not measure orignal waveforms before dismantled original ecu and wireloom from car.

But, if someone could measure...

Engine speed output is routed from Motronic 'ECU (55 pin) connector' pin 6 and signal goes to instrument cluster pin A7.

As what comes to controlling fuel consumption gauge, it seems that inside instrument cluster has some kind of adaptation module, which is engine type specific (size, number of cylinders etc.) - somehow it derives consumption from above mentioned tachometer signal and/or following two signals;

- vehicle speed signal: from Motronic ecu pin 29 which also goes to the instrument cluster.

- fuel rate output signal: from Motronic ecu pin 32 -> goes to instrument cluster pin A11.

Don't know for sure, but 'Fuel rate output' signal might be some kind of pulses per second or pwm signal ? Someone could measure ?

Hope these help ?

(or by phone# 1-2209238 in the evening)