Base Timing Idle Question
 

Looking to set base timing on a 1.6. When setting idle to 850RPM to find base timing to input into the MS, should I be changing the idle on the MS to 850RPM or should I be using the standard GND to TEN and using the idle valve. My car seems to idle at about 1250RPM even when warmed up. Turning the idle adjustment screw does not seem to have an affect on the idle. I am not sure the relationship between adjusting idle, the diag port, the stock ECU, and now what changes with the MS regarding this relationship. Sorry if this is a basic question, appreciate any help!

Using the diagnostic box is not necessary if you have megasquirt. What is your idle.set to in megasquirt? For the timing you need to use the timing let then you can adjust it to 10 degrees btdc in megasquirt without manually adjusting your CAS.

Idle is set to 1250 in MS. I guess my question is, do I need to set it to 850RPM to properly read the timing using the lights and the marks? 850RPM is the speed at which the Mazda workshop manual indicates base timing should be performed at. I am aware of setting the fixed timing in MS then using the wizard to adjust until MS and the timing read with the timing light match, but to perform this I must get a proper reading using the timing light and crankcase markings. My understanding is that the timing light works using the stroboscopic effect. Based on this, if my motor is spinning faster than the 850RPM that the marks were originally designed to be read at, I will read the timing more advanced than it is because the light will flash more often than it would at 850RPM. This is why I need to get the RPMs down to 850. Or, does the speed of the motor not matter because in the MS base timing guide it calls to set the timing at fixed when performing the base timing?

Can someone confirm that this logic is sound?

Put your timing light trigger on cyl 1 (closest to front of car)
Set the fixed timing in TunerStudio (this is the analog to stock ECU and shorting diag connector)
Adjust fixed timing +/- in TS while using timing light (this is akin to moving the CAS if you still had stock ECU)
Adjust the timing +/- in TS until the timing marks align just like the pic in the service manual tells you to
Turn fixed timing back off in TS

Then get your idle speed set where you want it via tuning/idle screw. This is independent of base timing.

I believe the timing light strobes based on the probe you clamp around the plug wire, so its firing at the same frequency as the spark plug is firing. So idle speed shouldn't matter. Can anyone confirm?

Truthy

This makes sense now. Thank you everyone for the help!