What’s the fix to make it read properly

It’s always read upto 3000rpm with the Adaptronics
Trying to get it right with the new ecu, still no luck...

There used to be a diagram on here for the fix...
Or I’ve read about a screw to adjust resistance on back of rev count?
My clocks are 1990 carb clocks


This is the next option to try...

 

Stuck a efi clock in it.

 

Although thinking about it I might have gone back to a mfi tacho when I went from cossie management to Megasquirt. I have a relay behind the dash like in that diagram.

 

Wire the rev counter to the coils using 3 diodes as per this diagram

 

Cheers for the replies...
Fingers crossed we can get it working right

 

That’s how it is now, only reading upto 3000 rpm

 

That's a tacho fault or you have a diode around the wrong way.
d3 is a zenner diode and is fitted in reverse as per diagram.

 

 

Good news

 

I tried this a while back (about a year) but I couldn't get it to work. Had the zenner diode in reverse as per diagram and the two - pins of the coil along with their dioide. The only time the rev counter moved was when the engine cut out and the needle spiked a little. Otherwise it read 0 all the time. Tried 2 different sets of diodes, no change. Rev counter works but at half revs as expected. Any thoughts what I'm doing wrong?