Thanks for the quick reply ed t. I will try the crank sensor in the morning. Pretty sure the 4.3 is not adjustable in this respect. If I probe the harness and rotate the motor by hand I should see a change in value though if it's working right? I should have added that I had the front of the motor apart to change the internal balance shaft bearings. Timing gears lined up after 5 rotations before it went together. However I obviously had the crank sensor out and off.