Tacho problem with vems

[Jyrarrak]

Hello,

I have problem with audi digital tacho (green, used in urquattro and some other models). With vems 3.3 motr55 plug'n play unit tacho works as should, but if I use vems 3.3 (1.1.88) with ec36 and ec18 pinouts tachometer dosen't work. In vemstune it works. Tacho signal is from EC36/04 and and in vemstune tacho is set to the same pinout. Cable between vems and tacho is ok.

Any ideas what seems to be the problem?

[ian4455]

Remember when i did my Esprit on VEMs there was an output that needed to be configured for the number of cylinders or pulses.

[S2central.net]

I think there is something funny about the digital tacho... What I suspect is that it is driven by pulses per minute in some specific format - whereas S2 tacho is driven by a voltage level. I would need to dig out some books to confirm this, but at worst a simple voltage to frequency chip could probably convert VEMS output to the UR clocks... Or is there a special config menu in VEMS for defining to RPM output signal.

[Jyrarrak]

If I tried friends vems 3.3 with motronic 55 pinout (plug'n play to audi) tacho works perfectly. But with mine vems (EC36 and EC18 plugs) tacho don't work. Adapter cables between vems and car motronic plug are correct. Maybe some parameters with vemstune need to be change but I have no idea where or how...

[Jyrarrak]

Problem solved. Moved tacho wire from p259ch0 (EC36-4) to logical ignition channel 07 (EC36-10). P259ch0 signal was too weak.