I am not having any luck with getting my megasquirt to function properly over 3400 Rpms. I have the V3 board and I have tried runnign the opto circuit 2 different ways but I get Tach spikes over 3400 rpms and it makes the motor brake up. I tried the VR circuit but cannot get the motor to run. It will start and die. I tried adjusting the resistors alot but no help. I am running my crank sensor off the 5v supplied by the MS. like I said it runs like a clock under 3400 rpms. I am getting frustrated with this. Has anyone had success with this? I am complete standalone. No ecu at all.