MS only fires on cyls1&2 or 3&4 with COPs
 

Having a strange spark issue with my ms1 v3.0 board. I'm using a modified ignition system with toyota cops. Everything works great when the stock ecu is plugged in and I get spark on all four cops with all four cops plugged in. When MS is plugged I get no spark when all 4 cops are plugged in, but I get what appears to be correct spark when only the cops for cyls 1&2 or 3&4 are plugged in. I thought it might be an issue with either Spark A or Spark B being disconnected on the main board...but that doesnt make any sense since doesnt that output control cyls 1&4 and 2&3? The rightmost led (d16) flickers faintly when I crank it, but d14 lights and does not flicker. I took apart my whole wire harness and did continuity checks on all the pins in my db39 to miata plug harness. Everything looks good. I checked all the solder joints on the mainboard for the modified spark outputs and resoldered anything questionable. Injection pulse is good on all four cylinders. Any other things I could I check? Any ideas?

Sounds like your spark outputs are built incorrectly. What value pullup resistor did you use?

1kohm. Also put a 1kohm resistor between b+ and ign- in the diagnostics box as instructed in the cops writeup.

I attached some pics of the board

Replace the 1k ohm pullups with 100 ohm 1/4 watt.

Tried 1/4 watt 100 ohm. No spark. Tried 330 ohm instead. I now have spark on cylinders 2 and 3 and d14 flashes rapidly. D16 does not flash. No spark on cylinders 1 and 4. Tried comparing the results to the stock computer...the stock computer sends out about half as many spark pulses over the same time interval and still sparks on all cylinders. I'm thinking the issue may be with the CAS output on IAC1A. Would replacing the highlighted resistor (see attached) with a 330 ohm hurt anything?

no that one needs to stay at 1K,


the other two need to be 100ohm (on d14 and d16)

Its been fixed! I replaced the 330 ohm resistors with 110. D16 in tunerstudio was set to accel instead of Spark B lol. Did a reflash and I'm getting spark on all cops.