1992 M30B35 with 179 DME momentary ignition losses when cold

[dmuffley]

I have an M30B35 from a 1992 E34 using a 179 DME. Engine loses ignition for less than a second numerous times when started cold (<75F). Engine runs rough and rich (A/F around 10-12) as I try to maintain RPMS above 2000rpm while the ignition (and tach) does multiple momentary drop offs. Once engine gets warmed up after about 2-3 minutes of doing this, I can let it go to idle. A/F increases to 13-ish and then transitions to 15-17 at idle after about 4-5 min. Ignition and tach cutouts then go away for the most part. I have replaced EVERY sensor (including VAM and ignition wires to get a new pulse generator), the coil and have tried multiple 179 DMEs.

So...what else could cause the momentary ignition cutouts when cold?

[dmuffley]

UPDATE: This whole issue ended up being solved by replacing the engine harness. Even though I checked continuity between sensor connector to ECU connector, the fact that temperature was involved made me wonder about wire or connector issues. Not only did the engine harness change fix the cold start issue, the engine has NEVER run this good since I first built and then installed it in 2018. Another BIG reason for improvement is that I ditched everything I got from SSSQUID. What a WASTE!!!