I followed Aaron Cake's writeup, like I'm guessing many others did, for initial startup settings. I think it might just be outdated data from an old firmware but MS3 firing order should be 1,2 not 1,3 in "Engine and Sequential Settings". That really matters if you have entered actual injector dead time curves that are different for primary and secondary injectors. It's not clear but changing the firing order in will change the dead time injector channel. That is obvious for fuel trims as the labels reflect Cyl #, but the labels are A, B, C, D in the dead time table!

If you want to test this for yourself, change your dead times at idle when the secondaries should not be active. Injectors A and B should be your primaries so changing dead times for C and D should have no effect. if you have firing order set to 1,3 dead time settings for C will be your rear primary and swing your AFR accordingly. Change firing order to 1,2 as it should be and everything jives. I would think this would be made clear in the hardware and setup docs on msextra Manuals for Megasquirt-3 - Megasquirt EFI but the info there isn't clear and, in some docs, shows the wrong coil order (MS3base/V3.0 Hardware manua).

If I marinated my brain in too much CO and premix smoke please chime in with a correction.

 

Definitely post this to the msextra forum!

 

I saw this and your thread on MSextra when you posted them over winter but had not the opportunity to test this.

I didn't notice this on my own car because I run a square injector setup and run no trims. A friend of mine has a new build with ID1300 pri and ID1700 sec. The idle keeps hunting even when disconnecting the IAC and the AFR was erratic. Initially I thought it was air related.. bad intake mani gasket.

He has the firing order set as 1,3 like everyone else and as a test, I told him to change his injector deadtime - injector parameters setting to "same" (all referencing table 1). He replied with "wow what a difference! The engine died" Obviously in a properly functioning setup that should not be the case.

Until reading the tooltip for 'firing order' in engine and sequential settings, I assumed it would affect the actual firing order of the coils. It apparently doesn't.

With that said, changing the firing order to 1,2 should be just fine. I will have him revert his deadtime settings back to individual and change his firing order to 1,2.