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.

www.cnnmotorsports.com

It's a 9v sensor. Try feeding it 12v, i've heard it will wotk off such feeds, otherwise, try building a 12v->9v supply for it.

Yeah that was next on my list... It does work wiht 12 volts. I also heard it works wiht 5volts . Thanks Dino. I have a regulator for the 9 volts too so I will probably just build that to prevent any problems.

www.cnnmotorsports.com

Works, sure... But i imagine the current draw increases with RPM, and that may be why its breaking up at ~3500RPM, it can't get enough current out of the MS's 5v supply.

ok Well I hooked up a national semi conductor LM7808CT into the mix and it is better but now it will break up around 4800 rpms free reving. I also get the tach spike like before. Dino what input are you runnign on your board? NER was having a similar problem with the opto but no the VR. I simply cannot get my car to start on the VR circuit.

www.cnnmotorsports.com