Converting negative reported timing advance to positive


Converting negative reported timing advance to positive

Application: GM V6 based vehicles

For many late model GM V6 based vehicles (those derived from the 3800 Series II platform) the factory computer will report positive timing as a negative number.

VCM Suite 2 allows two solutions to this:

Solution 1
Create a user defined PID and insert into the table as follows: How it works: The scanner will average the values of all sensors of same type currently being scanned. What we have done here is create a new PID that returns 3x the spark advance in the positive direction so that when it averages the two values you get the actual spark advance in the positive. You shouldn't have to change your histograms, charts, gauges etc. as they all log as sensor based by default.

Solution 2
This method is similar but uses -1.0 * [PID.14] as the function. You would then have to go switch your histo's and charts etc. to plot the PID value rather than the sensor value.