3406e bad ecm? Missing, sputtering and white smoke at startup

Are you losing any anyifreeze

 

What's your fuel pressure. Do you have a gauge.

 

I would start with the fuel pressure and change your filters. Doesn't seem like a computer issue to me even though you say one is better then the rest. Do you have a prolink. Do a cut out test. Or go to cat and do a 4 cylinder cut out test. That one works the best. A 3406e will run on one cylinder so it's best to do the test where it shuts on 4 cylinders to test 2 at a time. I would be looking there.

 

Might not be a bad idea to do a compression test either.

 

I would suspect the one ecm that makes it runs good probably is a lower horse power rating with different timing to produce a smoother running engine. I also think you have a fuel or injector problem. I would never suspect a bad ECM until all other diagnostic paths have been exhausted. ECMs are pretty tough and rarely fail. I would also go over all your powers and grounds to make sure they are clean and tight so the ecm is getting good clean power. Then check into your fuel for proper pressure and any aeration.

 

I'm not trying to take the wind out of your sails but that is classic early signs of head gasket failure. When cold the compression on the bad cylinder is low enough to not fire off completely. Causing your missing and white smoke issue. Once some heat gets into cylinder it will run and fire normally. It will gradually get worse and worse.

Like heavy D said . Other ecm might have different timing or HP rating to not aggravate the problem as much.

 

Me thinks you've got an injector about to go out

 

I agree with the head gasket actually. Same thing happened to a 3176 I had in a service truck once. Popped white smoke for a while at start up and ran normal once it got warm. It will go soon.