Wiring chart.. where did I get this???

[Jon K]

What manual is this from? I need the rest of it!

[aston_jag_tech]

try this Jon, http://www.e38.org/e34/

[winfred]

that's the bmw etm, i think theres a few online copys running around here

[Jon K]

Winfred - I really need help understanding the factory tachometer... what sort of signal (voltage etc) goes over Pin 74 to the tach? I used a DMM and found 6.1 volts at it but that doesn't make much sense to me - if its a 5v signal that's a lot more volts... can you provide any info?

[Espen]

The tacho signal usualy come in digital signals/pulses, you will need a oscilloscope to read its signals. Im not sure if this applies to the e34 though.

[winfred]

i don't know what signal it's sending haven't had to screw with one yet, seems to be one of those things that doesn't break

Winfred - I really need help understanding the factory tachometer... what sort of signal (voltage etc) goes over Pin 74 to the tach? I used a DMM and found 6.1 volts at it but that doesn't make much sense to me - if its a 5v signal that's a lot more volts... can you provide any info?