I've been struggling to get the cold tuning of my '93 GMC C1500 truck with a 16168625 ECM perfected. The engine is not stock but between me playing around and using some files from a tuner it is very close.

The truck runs just about perfect once it gets some heat in the system. But cold (especially when the outside weather is below 45 degrees F) the engine runs rough and looking at the O2 output operation is fairly rich in open loop. Once warm and in closed loop all is fine. We have tried taking some fuel out of the map in open loop operation a couple of times but we are sort of working blind and only know once in closed loop the ECM is doing a bit of correction to lean out the fuel map. Until we can data log we don't want to remove more fuel in open loop.

I'm stuck taking "snapshots" of the ECM operation with a Snap-On scanner as live data logging has both myself and the gentleman assisting me with the tune perplexed. The software options he is familiar with don't seem to get along with the 16168625 ECM and I haven't found a working alternative in my digging around.

Does anyone have some options for data logging this ECM?

Thanks