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Question for all you guys. I have a 1996 Chevrolet Tahoe with a vortec 5.7. While driving the vehicle the ignition timing shows a negative value (-25 as an example).
I did some work on a friend of mines 1997 Chevrolet Tahoe with a vortec 5.7, and noticed that while driving the vehicle his ignition timing showed a positive number the whole time.
My question is why does one show negative and one show positive? Is this a difference in the system from year to year? Can the distributor be installed 180 degrees out on these and the computer just corrects it and this is the result? Both vehicles run fine with no check engine lights.
Any help on this would be great, just trying to learn why or how it could be different on what I believe is the same system?
