View Full Version : How to pull tach signal for aftermarket ECU on M50?


5mall5nail5
12-10-2005, 03:17 AM
Anyone know? Can't use hte coil... since there are 6... what should I do?

Croak
12-10-2005, 04:21 AM
Pin #1 on the diagnostic connector in the engine bay should be your tach signal, easy to tap. Bentley is your friend.

5mall5nail5
12-10-2005, 11:37 AM
Pin #1 on the diagnostic connector in the engine bay should be your tach signal, easy to tap. Bentley is your friend.


Croak, even though I am OBDI?

Geno325is
12-10-2005, 12:05 PM
Croak, even though I am OBDI?

yup, even on OBD1

5mall5nail5
12-10-2005, 12:08 PM
yup, even on OBD1


I got different response...

someone said

Pin 15 - RXD
Pin 20 - TXD

???

Geno325is
12-10-2005, 12:23 PM
I got different response...

someone said

Pin 15 - RXD
Pin 20 - TXD

???

Pin 1 off the DIAG port...

patrick S
12-10-2005, 12:53 PM
How to pull tach signal for aftermarket ECU on M50?

you mean you have aftermarket ecu and you want to get your tach work?
or you want to get tach signal for aftermarket ecu ( which makes no sense)
you have to be specific
what ecu??
there are always wiring diagrams for aftermarket products included in box.

black wire in diagnostic port- but you did not specify if you removed original wiring from engine
six coils? use diodes- if you dont know how, dont even try

5mall5nail5
12-10-2005, 01:13 PM
you mean you have aftermarket ecu and you want to get your tach work?
or you want to get tach signal for aftermarket ecu ( which makes no sense)
you have to be specific
what ecu??
there are always wiring diagrams for aftermarket products included in box.

black wire in diagnostic port- but you did not specify if you removed original wiring from engine
six coils? use diodes- if you dont know how, dont even try


Megasquirt ECU requires a tach signal INPUT for datalogging - Which makes sense.

there are two types of connectors:

http://www.unofficialbmw.com/images/reset5.jpg

That is the one i have, called a "data link connector"

Then there is this one:

http://www.unofficialbmw.com/images/reset8.jpg

Which I do not have.

I found this pin-out:

http://www.unofficialbmw.com/images/reset2.gif

But I'd like to be sure "TD" is what I want, that's not very descriptive.

Also, you can leave your ignorant comments in Estonia, thanks.

Croak
12-15-2005, 05:16 PM
"Data Link Connector" Pin 1 will do the job. Unclip the the whole connector assembly from the strut tower bracket, lift it up, find the wire going to pin 1, tap it, you're done.

And yes, "TD" is the tach signal.