BMW E30 Tacho not working

[knastbigger]

Hi

My 1985 E30 tacho is not working with EMU. I have swaped the old M20 out with a M52.
I have tried with one from a Toyota Supra, and it works.
I use output AUX4 (G20)

Belive it maybe has something to do with the old schoole coil on the M20, any suggestion

BR Lasse

[Jan32]

You cant use the emu signal for these old tacho. It needed the old signal (terminal 1) from the single coil. (Up to 100v peak and emu has only 12V)

[knastbigger]

Hi Jan

Thanks, what I was afraid of I will buy this Dakota Digital Universal Tachometer Adapter SGI-8. I have tried one before where I should convert the signal from 6 to 8 cyl, it worked fine

BR Lasse

[Jadzwin]

You should be able to drive the tacho by EMU but you need to make a "trick".
Your tacho requires high voltage signal. You can try to simulate high voltage signal by using inductor.
For example you can connect a car relay coil between EMU tacho out and +12V.

[RHD]

Ok i have done lots odf work with e30 and m20 engines and i have just used the aux #4 and it worked no problems but recently i tried one e30 and couldnt get it to work! e21 tacho currently works no problems too.

have there been any changes to the driver with the newer firmware? the times it worked were all on the older versions, this may be coincidence.

[derOJ]

on my e30 its also working.
i had to set a scale factor of 3 to adjust rpm, but no problems. i also use aux 4

[knastbigger]

Hi all

It has been fixed. There was at red/green wire pin 2 in the white connector that should have permanent 12v. There was a bad connection in fuse 21 so no power to the tacho.

BR Lasse