It "helps reduce pinging when snapping the throttle". The document I linked above describes ignition timing and the roll of "vacuum advance" pretty well. It might also help to read the ACCEL IGNITION TRIM doc in the NismotronicSA help. It will show all of the criteria that must be met in order to invoke TPS ignition trim, which is also a function of the stock code.
Last edited by OnTheChip
on 2014-08-04
at 20-58-18.