Bart-Jan

Can anybody post the electrical circuit diagram of the rev counter/ tacho meter of a 928? Preferably of a '85 Euro S, if there are any differences.

Speaking of differences, what electrical difference in schematics is there between the single distributor rev counter and the dual one?

I still have double amount of revs that I read and cannot get Lizard's ideas to work. My preference is to use the EDIS tach out signal for this function, but then I need to change something to half the revs. I could add a flip flop, but since a tach is a voltage meter fed by digital signals, it needs to convert anyway. I guess this conversion circuit could easily be changed.

Thanks!

Bart-Jan

Nobody?
Not even a clue?

John Speake

Where are you taking the tach signal feed from ?

Bart-Jan

Hi John!
Nice speaking to you again. I took the signal feed first from the EDIS no. 2 pin; This is intended for tacho out.
I tried hooking up the rev counter with diodes, as per proposal from Mechasquirt forums. I finally tried programming the rev counter on one of the outputs of Megasquirt. Both the last options didn't work; probably the rev counter needs higher voltage pulses? Easiest for hooking it up is to the EDIS output, but then I need to halve the amount of pulses. Any idea?

John Speake

The 928 tach requires a nominal 12v signal to work so if the MS gives 5v then wouldn't be adequate.

The rpm pulses fed to the 928 tach are in fact at 2x engine speed.