ok heres my msq. if you an find something let me know.

 

iirc, I don't think the trailing table likes negative numbers ... and I believe any number 20+ also disables trailing. Did you try setting the trailing timing fixed and time it with a light?

 

I'm not sure what negative numbers will do, but numbers greater than 20 will definitely turn off trailing.

Ken

 

I figured it out. i found a bad ground on the 300ohm resistor on the lm circuit. im not really sure how this affects the trailing though. i found it by accident when i was handling the circuit. trailing now fires and the stock tach works. im not sure but i think there is some error with the stock tach. it says im idling at 500 rpm or less. i couldn't confirm the idle on megatune because i left my laptop at work.

 

Sometimes the stock tach can be off a bit.

I've seen them off by up to 300 rpms.

Ken