MS1 V3.0 running spark only - no start

[cwdodson88]

I have a MS1- pcb 3.0 using extra 029y firmware. It has been running SPARK only and working out pretty well. Using MSnSe extra code and Crane Optical sensor for RPM input, single coil, BIP Coil Driver, MS Droid over Blue tooth, Bolutek BT-RS232 adapter with homemade x-over cable.

So issue, I get tach signal on MsDroid while cranking (approx 220 RPM), WB figures look normal, AFR readings looked normal, cranking spark timing looks normal, but no fire. I haven’t checked to see if there is actually spark happening. (This all happened when trying to start/warm the car up to go to work this morning) My tach (that is connected to the coil-) flicked like normal when the key switched on, but not while cranking. Previously it would bounce a bit while cranking, but now it flicks once and sits there. Symptoms of a dead coil? Should I have run my tach from the MS box?

I had done a firmware re-flash a few weeks ago due to a similar issue, but I never figured out why a re-flash worked and what I did to screw it up in the first place. And now that I go through it, I’m not sure if I disconnected the coil when I flashed the firmware last time... could that have anything to do with a no start scenario?

[mazdaspeed]

Id say you on the rite trak. Put a 12v bulb across the coil -ve and +ve if the ms is ok it will flicker when cranking. If i does check for spark if you have no spark it would be a fried coil.

[DaveEFI]

Remove a plug (or use a spare one), connect it to a plug lead and clamp to a ground. Crank the engine - you should see a good fat spark. If no spark, do the same from the coil king lead - to eliminate the dizzy. If no spark, either the coil (or supply to it) or driver. If all ok use a timing light again when cranking to check the timing is near enough.

[cwdodson88]

Well, I think I figured it out. Coil overheating possibly from having my dwell set too low, or loose coil connection... But I'm not too sure.

Last night, I plugged it into my laptop and didn't change anything and it fired, ran somewhat, so I added a bit of dwell in the running and cranking (2ms to each) and it ran way smoother. So I took it out and ran it through the gears and the thing seemed like it just wanted more. I added another 2ms of dwell (totaling 7ms running and 8.5 cranking) and it started to sputter on throttle jabs, pulled the dwell back in .5ms increments until it did better with throttle jabs from idle, and now it sits at 5ms running and 6.5ms cranking. Took it out again and it pulled fine until my 4500 rev limit, so upped the limit to 5500 and it kept pulling. So I started it this morning and all was spot on. My AFR (using HIF6 dual carbs) was a little richer than before, but I'll just drive it like this until I get the fuel side going in a week or two.

Thanks guys for all the help!