rpm problem
 

I have 1993 RX7, I 20B engine but the problem that I have is that is not giving me the right RPMS, when I driving 50MPH, the RPM are 3000, some guys told me that I need something like RPM signal for 20B, if someone knows how to fix this problem please let me know at mazdarotary20b@bellsouth.net. Thanks

You're putting out three tach pulses to a tach expecting two. I used to have a device made by Russ Turner that split the difference. Now, I have a Tec3r for my engine management, and it has that feature built in. There are commercial units on the market, mostly for people who have converted to a V8 from a V6. Google is your friend.

BTW, I tried sending that to your email address. It was bounced.

I forgot to say in my massage that I have 20b engine and Microtech LTX 12 in my 1993 RX7 and the problem give wrong RPM

Universal Tachometer Signal Interface
http://www.dakotadigital.com/index.c...rod/prd127.htm

As posted here, you need the Dakota Digital device for your Microtech to work properly. I had the same issue and the Dakota fixed the problem. It costs around $80 or so.