Which pin on E38 for Tachometer?

[GAMEOVER]

I can't find a pin assignment for Tach output on 2008 E38. Is there even an output available like pin#10 on ls1 pcm?
Aftermarket tachometer....

[Taz]

Hello GameOver,

If E38 Tach output is changed from serial data to crank (for aftermarket Tach), the output is supposed to be connector C1/X1/J1 (black) pin 48. I have never done this - just in a pile of R&D files I’m collecting.

Hopefully that is correct ……


Regards,
Taz

[GAMEOVER]

Thanks TAZ....Always helpful!

[GMPX]

Depending on the Tacho, you will need to add a pull-up resistor to 12V on the output. 1K Ohm should do the job.

[GAMEOVER]

Depending on the Tacho, you will need to add a pull-up resistor to 12V on the output. 1K Ohm should do the job.

Ok Cool....

[Redline Motorsports]

I have to double check but we always pulled a wire that was in the coil wiring harness to run a MSD window switch which required rpm...let me see if I can remember which one it was!

Howard

[GAMEOVER]

I have to double check but we always pulled a wire that was in the coil wiring harness to run a MSD window switch which required rpm...let me see if I can remember which one it was!

Howard

Really, in the coil harness...

[Taz]

If you’re referring to splicing into the ignition control circuit of an individual coil - this would yield a 1 ignition pulse per 2 engine revolution output. This type of signal might be compatible with an aftermarket Tach - not sure about cylinder mode setting of the Tach (probably set to either 8 or 4 cylinder mode).


Regards,
Taz

EDIT: Recounted the ignition pulses (using all fingers, and some toes - think I got it right this time !)