TACH SPIKES & DROPS - 420A decoder; V3 board; 024s13

[turbodoug]

I'm getting constant tach spikes & drops using 420A decoder in a V3 board with code 024s13.

Ignition consists of 2 VB921's that are firing a Crane HI6-DI2 ignition box. MSnS running fuel and spark. The tach spikes/drops occur even when running stock ignition system. It's bad enough that the car jerks every couple of seconds. I'm using the opto circuit - NOT VR. Engine runs great except for these tach spikes/drops.

Is there anything I can adjust to clean up the crank signal? Maybe even adding resisters or something? I'm pretty darn familiar with the MSnS stuff, as I've had almost 10 successful V2.2 installs. This is my first V3 install.

Any suggestions guys? Any help would be much appreciated, as I need to get this customer's car back to him. Thanks.