Although a reversed installation of the driven plates is a possibility, the greater, and more likely possibility is the angular displacement of the ring gear/trigger wheel. The gear/wheel can be assembled to the plates at 120 deg. steps, but the trigger segments are at 90 deg. A mis-assembly in one direction would advance the timing 30 deg., and a mis-assembly in the other direction would retard the timing 30 deg. As soon as the EZL detects "engine running" a small amount of advance is provided from the internal timing mapping; 30 deg. retard minus ~7-8 deg. EZL advance = 22 deg. retarded!