I'm having trouble getting any kind of spark during cranking, or seeing any kind of signal from my crank angle sensor in Tuner Studio. Any help would be greatly appreciated. My setup:

85 GSL with the "factory" 12a
Megasquirt v3.57 plug'n'play ECU with MS3X expansion from DIYAutoTune
FC CAS
MSD 6A with 2 MSD Blasters running wasted spark (no trailing)
EFIHardware side draft with 4x646cc injectors
FC S5 Turbo

I followed AaronCake's amazing guide, supplementing with the MS documentation since my setup is *bit* different from a stock FC. I used Aaron's fuel and ignition maps as a starting point. All of my sensors seem to be working except for the CAS. When I crank the engine, I don't get any signal in the composite logger and writing to a log file yields a blank file. There's also no measurement from the tach on TunerStudio's dashboard. The CAS checked out when I tested it with a multimeter. Resistance values were right in the middle of the range and none of the wires grounded out. The connector is in good shape. The MSD is working and connected correctly, as I can run a coil test in test mode and trigger spark that way. I'm wondering if I have something set wrong in Tuner Studio, or perhaps have wired something incorrectly. Here is a rundown of my ignition wiring:

CAS red -> White shielded MS3
CAS White -> Black shielded MS3
CAS Green -> shielded wire -> MS3X Green CAM IN
CAS White/Black -> shielded wire -> MS3X sensor ground
Green/Orange MS3X TACH OUT -> White MSD 6a signal input

And here are my ignition and crank settings:

 

Did you set the potentiometers on the MS board correctly? Maybe try setting ignition input capture to falling edge, if that doesn't work try setting the second trigger active on to falling edge, if that doesn't work try setting them both to falling edge.

 

Thanks for the reply! The kit I bought is a pre-built unit, so there wasn't anything to set that I'm aware of.

I tried your suggestion of setting the input capture/second trigger active to falling edge. I tried every combination of settings but still got nothing logged and no RPM reading. I'm honestly stuck at this point.

 

What you said got me thinking that maybe I missed something, so I re-read Aaron's guide. Turns out I skipped a whole step when setting this thing up because I thought it was a full plug-n-play solution like the MS3-Pro. I took the MS back apart and set the jumpers correctly. I tried to adjust the potentiometers by hand since I don't have an oscilloscope, but I couldn't hear or feel any kind of click.

Long story short, I hooked everything back up and still no spark or RPM signal during crank. I think the MS is just losing sync while the starter is engaged. I pulled the CAS out and turned it by hand with the key on, and I could hear the MSD spark and the injectors fire. I also finally got a bit of log data. So now I'm thinking bad ground somewhere? The battery is brand new and charged. I'm going to go over the grounds tomorrow.

 

I regrounded everything to the rear iron instead of the chassis. Probably needed to be done, but not the root cause of my issue.

Advice to anyone with the same issue: make sure your power source to the Megasquirt is powered with the key in the START position, not just ACC! I was running off my custom fuse block for my gauges, which was powered through some factory accessory wiring probably related to the radio. That stuff is made to switch off during cranking. Not a good source for your ECU

I'll rewire all that, charge the battery, then have a look at the composite logger.

 

A quick test of my wiring turned into a test of my smoke alarm. It started right up. Idle was rough, with a lot of blue smoke. I could only keep it running for about a minute, even feeding it a little throttle. AFR was 10-11. But much better than a few days ago when I couldn't even get a spark.