MS3x brain-built first start up issues
 

Hey guys, been trying to read as much as I can but I need some guidance or prodding in the right direction.

First off, my 2001 Miata is bone stock other than a cold air intake, aem wideband and an MS3x w/ GM AIT sensor. Mechanically sound, new coils after MS3x fried my coils. Runs smooth when swapping back to the factory ECM. No other mods so far.

I've been following brains' installation guide as per (guide in first post), its laid out in a simple enough guide for the life of me I can't get this thing fired up so I can start tuning it. So basically where I am at right now is the first start up after plugging everything in.
I have calibrated the TPS, Coolant thermistor values, air intake sensor and O2 Wideband selections. Fuel Req is 11.4ms (already inputted in the basemap when it was shipped to me)

The next step on the guide is to start it up and idle it so I can set the timing in Tunerstudio. It just cranks and stumbles and backfires out of the intake. I have uploaded a that shows whats happening. It does have some ignition events and it feels like it wants to start. I only managed it to get it started once or twice but this is after a long time of cranking and playing with the throttle and when it catches I have to keep it alive, if I let off or don't jab at the throttle to keep the rpm up, rpm drops and the engine dies. I'm more concerned of the long crankinig and back firing at this point. I know the idling can be tuned but evey time it dies its a bitch to get it going again.

The only thing catching my eye is perhaps its too lean as the AFR is high as I'm cranking. After further inspection of the plugs, its a bit black but not overly, and not wet. But if its backfiring, isn't it overly rich?
Another question is when I'm cranking the sync loss count goes up, usually when its cranking and getting an ignition event (sounds like it wants to run), is this normal?

I haven't even set my base timing yet, I feel like with the basemap it shouldn't be this off for me to atleast get it going and idling. Just comparing with my experiences I had with my 92 MSPNP, it didn't have this hard of a time trying to get it going, at the very least, roughly started. Any thoughts of where to go from here before I start playing with cranking pulsewidths and fueling?

I have attached the current msq and composite log.

Thanks for any help to point me in the right direction.

I just installed MS in my car a few weeks ago and initially I had this same issue with starts. You are loosing sync way to much during crank which is what is causing the backfire. Ideally you should never loose sync even when cranking. First off under ignition options try changing "ignition input capture" to "falling edge" This greatly improved signal quality for my setup. Also if you haven't already you need to turn R56 about 8-9 turns clockwise after turning it fully counter clock wise. This is critical or you will never get a sync.

You say "bone stock other than a cold air intake with a MS3x w/ GM AIT sensor." Do you have a wideband?

Whoops. I'll edit it now. It's an Aem x-series wideband.


@shotgreen thanks for the tips. I just reset the pots according to trubokitty.com, going to report back later. And I'll switch back to falling edge. I switched it because I read conflicting posts and decided to give it a try as it did seem like it gave me less losses, according to my newbie eye.

Still doing the same thing after adjusting the r56, r11 and r32 pots to what was directed.

I've attached a datalog of the cranking events

You are going to need to do a composite log under high speed loggers. Start the log and crank to car for 5-10 seconds then stop the log. You should see a green line(CAS signal), Blue line(Crank signal) and red line(Sync loss). You may need to adjust the view using the buttons in the bottom right corner to correctly see the lines. Once you have the log take a picture and upload it.

Cranking log was already posted in the original post with about 10 seconds of crank time under a battery charger.

Fixed. Had the megasquirt board examined, found some burns marks on the pcb board and had it repaired. Starts up on the first try. Thanks guys.