Re: Crank sensor position?
As in earlier systems that are adjustable by turning the distributor, setting the base initial timing off usually creates drivability problems. It assumes it's starting it's advance from a certain place. If it's starting from somewhere unkown -- it's lost.
If you "think" you are in New York but you are really in Dallas, you too are confused. Same thing. Ya gotta know where the beginning is.
Yes, at start-up it looks at the sensor as altitude. That in itself could offset the mixture. If you were actually at 2000 feet, but the new variable MAP voltage "tricked" it into thinking it was below sea level, it would end up rich. But richer didn't make much difference (as adding propane proved,) as it's already optimized.
The way the advance works is it's always trying to advance more and more, no matter where it started from. It keeps advancing till the knock sensor bumps it back down. That point is the optimum timing under that instantaneous speed, load, mixture, altitude, temp, throttle position etc.
Rockette products, and others, have an adjustable crank sensor, but it's for the earlier 4.0's.
BTW - I'm just shooting in the dark here - tried the richer idea, didn't seem to help. Already helped the external breathing with the exhaust and intake mods. Next thing was the crank sensor and initial timing - but that would take some machining - and the engine to be pulled out to do it.