This is probably a stupid and quick question, but below idle (~8-900 RPM), the stock tach will drop off but the megasquirt one is still working... Any idea what I'm doing wrong there? It's disconcerting to throw it into neutral and see the tach just fall off.

Thanks!

 

If it's an MS1 than that's how the firmware was written.i.e. trailing ignition (tach source)drops off below 800rpm. IIRC it was some workaround to a bug or firmware limitation requiring substantial code rewritting to fix, or something to that effect.

 

It is an MS1, so at least I didn't screw anything up

Thanks!

 

MS1 doesn't fire trailing below 800 RPM. Oddly, I've also noticed trailing disappears when you go into the boost control screens, then reappears if you go into a timing related screen.

 

Ahh, I thought we fixed that one in later firmware. May have to find my old ms1 test MS and fire it up on the bench.

Ken

 

I'm on 029y4, if that helps at all...

 

I was talking about the one that Aaron mentioned. The stock tach dropout won't get fixed. It's a limitation of the timers we're using to set trailing timing on the ms1.

Ken

 

Ah, gotcha Ken.

 

my tach doesnt work below 800rpm in the car. I assume no signal is sent to the trailling coils, therefore no tach ref pulse for the stock tach.


MS1 v2.2

 

Wire the stock tach to the leading coil.