Mercedes 12cyl MS3 / MS3X timing question

[Tinkers Toy]

I have my car running smoothly on Megasquirt 3 & MS3X. Right now the car is running great using semi-sequential fuel only on Megasquirt and the ignition and knock is still handled by the Mercedes ECU's. Phase two is to add coil near plug ignition by adding GM LS1 coils and a trigger wheel in place of one of the distributor's on the front of the cams. At that time I'll go fully sequential fuel as well. My question is this, is there a way to set the timing without adding a temporary coil near plug and a grounded spark plug and using a wasted spark setting? I have not checked timing yet, since I'm only doing semi-sequential fuel only with multiple squirts per cycle is there any advantage to setting timing at this point? I would like to get the timing set before continuing with my tune. If I need to build a temporary spark setup to accomplish this now would be the time before I continue work on my tune and advanced idle settings.

Here is my build information.
MS3, MS3X, 4 channel driver board.
two GM cable driven throttle bodies using one of the integral idle stepper valves and blocking off the other and using one of the throttle position sensors and removing the other. A solid connecting rod ties the two throttle bodies together.
GM coolant temp sensor
GM air temp sensor
36-1 crank wheel and hall sensor
Innovate LC1 wideband O2 sensor

[Matt Cramer]

I have my car running smoothly on Megasquirt 3 & MS3X. Right now the car is running great using semi-sequential fuel only on Megasquirt and the ignition and knock is still handled by the Mercedes ECU's. Phase two is to add coil near plug ignition by adding GM LS1 coils and a trigger wheel in place of one of the distributor's on the front of the cams. At that time I'll go fully sequential fuel as well. My question is this, is there a way to set the timing without adding a temporary coil near plug and a grounded spark plug and using a wasted spark setting?

The LS coils are a CNP design, so they're straightforward to get a timing light on.

I have not checked timing yet, since I'm only doing semi-sequential fuel only with multiple squirts per cycle is there any advantage to setting timing at this point?

The Mercedes ECU is controlling the timing now - is there any method of adjusting the timing at present?

[Tinkers Toy]

No, the timing is all locked down by the Mercedes ignition ECU's and not adjustable. Eventually I will switch and allow MS & MS3X to control spark but right now the Mercedes Ignition modules appear to be working fine so I'm piggybacking those and just doing fuel. I'll check the timing with my light and see if the advance looks as expected but everything appears normal and running smoothly. Eventually I'll switch when the ignition modules or caps and rotors need maintenance, these Mercedes parts are astronomically expensive and make the conversion very cost effective. If I need to invest in a bank of coils to check MS timing then that's what I'll have to do. Eventually I'll need them anyway.

[jsmcortina]

Adding a temporary coil is about the only easy way that I can think of.

If you were running sequential fuel, you might be able to hook an inductive strobe up to injector A for a similar result.

James

[Tinkers Toy]

I never resolved setting the timing while doing fuel only but I installed phase2 and abandoned the Mercedes ignition, now I run 12ea. LS2 D585 coils. Setting the timing couldn't be simpler once I was using MS to control ignition as well as fuel.