cat10

Hi folks, just completed the assembly of my MS1 V3 for my MX5 MK1 1.8 1997 UK Spec, I have installed the fan and ignition mods as per the excellent "super important megasquirt threads "write up on here.
I built the MS1 V3 using the megamanual instructions..

I have a question about the Tacho output pin number coming off the megasquirt.....

I am making a stand alone harness for a 96/97 1.8 model but I do not know what pin # the megasquirt uses for the Tacho.

At the moment pins 20 to 37 are all being used for other things so I can not see what pin from the megasquirt connects to pin 4l on my cars connector, to get my Tacho working....

Any help with this would be great..

Joe Perez

iTrader: (8)

There isn't a dedicated pin on the MS for driving the tach. You need to build a circuit inside the MS to create the tach signal, and then connect the output of this circuit to any available pin on the DB-37.

Use the first illustration in the above link. The "selected pin on the PCB" can be JS0, JS1, JS2, JS3 (or a couple of others) depending on what's not already in use elsewhere. You will then configure the "Techo Output Pin" (under "More Settings") in TunerStudio / Megatune to tell the MS to use that pin to generate the tach signal.