Author Topic: tach signal (Read 6132 times)

jakeb · « **on:** March 29, 2008, 06:44:45 AM »

Does anyone know how the tach signal works? I have a m42 in my 2002 and trying to get the stock 2002 tach to work. I connected it to the signal off the c101 plug but not getting anything. So trying to figure out how I can get it to work or if I should go with an after market gauge.

I was able to really drive the car yesterday and it is fun fun fun. The sound when you stomp on it is pretty insane. I am running two straight trough magnaflows. I will have to take a short video of it.

christod · « **Reply #1 on:** April 07, 2008, 06:35:08 PM »

Jake,
Ive got an e21 with an m42 swapped in and Ive run into similar problems.
Heres a post string I started some time ago that should shed some light on the situation.

http://forums.bimmerforums.com/forum/showthread.php?t=946870&highlight=pinouts

Hope it helps!

christod · « **Reply #2 on:** April 07, 2008, 06:42:07 PM »

Also, if you want to spend a little money ($80 or so), this seems like the easiest and least finicky solution.

christod · « **Reply #3 on:** April 07, 2008, 06:42:37 PM »

http://www.msdignition.com/ignition_27_a_8913.htm

MLM · « **Reply #4 on:** November 03, 2010, 05:56:38 PM »

Reviving a old thread sorry..

I am wiring in an aftermarket engine management system which outputs a 12v pulse for RPM. Will this work with a E36 guage cluster or does it require a 5v signal?

What have others done for RPM signals to standard guages when using a aftermarket system?

Any info on what the guage cluste expects as a signal much appreciated..

DesktopDave · « **Reply #5 on:** November 04, 2010, 08:40:08 AM »

It might be that the tach gets an AC signal...and the MSD linky above is down. Here's a link for you (not sure how helpful it'll be): http://m3forum.net/m3forum/showthread.php?t=322373

If the car is still running, test that OBDII port pin 9 & see what it pulses at, AC or DC.

MLM · « **Reply #6 on:** November 04, 2010, 02:52:41 PM »

CheersDave,

I should have done that before i yoinked out the the loom and ecu. Hindsight is a wonderful thing.

I know of others running my ecu in e30's and they connected it right up but i just want to tripple check before blowing somthing up. I have the option to adjust duty cycle etc on the ecu so may start concervative and work up..

DesktopDave · « **Reply #7 on:** November 04, 2010, 03:56:55 PM »

I'm pretty sure it's not a very powerful signal...I'd be willing to bet that 12vac and 5vac will both work. YMMV The caps in the cluster are cheap but not so much fun to replace.