pascal.1605

Hey,
the Tachometer on my 1992 Turbo Miata (3 Wire Coils) currently doesn't work after switching to Megasquirt and I have a few questions about the Enable Tacho funktion in Tuner Studio.
I've heard that messing something up here can Damage my Coils so I'd rather ask for advice first.

When enabling Tacho Output what "Output" and "Speed" should it be on ?
It says at the bottom "be sure nothing else Uses this Output", how do I know if an Output is allready in use ?
Is there Anything in the "Ignition Options" that needs to be changed in relation ?
What about "Spark A output pin", Should it be the same as the "Tacho Output" ? (By default my Tacho Output is on D14 which is also the preferred "Spark A output pin").

I have the 3 Wire Coils and a MsLabs Basic MS2 Ecu.

Would love a reply as I coudnt find anything about this Online.

curly

iTrader: (25)

Spark output A and B are typically for triggering your coils, A=1/4, B=2/3. You'll use a third output for tacho.

The MS outputs are unfortunately horribly labeled, you'll have to find one on your ecu/firmware that works.

The speed doesn't matter, if your tacho is randomly showing twice the RPM is should be, you'd want to select "half speed", however I believe most setups use "normal".

Reverant

iTrader: (10)

1992? Your tacho is not controlled by the ECU but from the igniter module that is on the passenger side fender. Are you still running the stock coils?

pascal.1605

​​​​​Honestly, idk. The previous owner might have given me different generation Coils since they were in a parts box and the Car was thrown together with different gen parts all over the place. They are 3 Wire coils though, idk if the 3 Wires changed over the Years. I'll attach a picture.

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Reverant

iTrader: (10)

Looks like you got a parts car, so you don't know if the tacho worked before, right? In that case, it is safe to assume the igniter module is bad and you need to change it.

pascal.1605

Yes you're right. I've never had the Car on a stock ECU, I did however swap out the Igniter Unit for a known working one from my other Miata

Reverant

iTrader: (10)

In any case, with stock coils and the igniter module, the tacho signal is generated by the igniter, and the signal goes from the igniter to the cluster through the yellow/blue wire on the igniter. If the igniter has been swapped out for a known good one, trace the connection from the igniter to the cluster and make sure everything is ok.

pascal.1605

I had the Cluter out when I installed Electronic ABS, maybe I damaged / unplugged a wire or something. RPMs do work in Tuner Studio btw.