Idle Tables

[Revchux]

Can someone give me a quick tutorial on what the different IDLE tables control

[wcs]

I found this in the Cobb Tuning Access Tuner Race PDF.
If you ever used the old Cobb ATR tuning software it is very very similar to VT.

Personally I don't find Cobb's description very helpful, but I thought I would throw it out there for you.

Idle Speed
Table description – A single row of target idle speeds that vary as a function of engine coolant
temperature. The various tables in these series (A through E or 1 through 7 in VT) are indicated by an an assortment of
conditional parameters.
Tuning tips – When running larger fuel injectors we have found it has been helpful to maintain an Idle
Speed which is 100-400 RPM higher than the factory calibration. At idle, the vehicle is in closed-loop
operation trying to maintain 1 Lambda or an AFR Petrol of 14.68:1. The ECU might modify the injector
pulse width (IPW) to a point where the ECU will not allow a fuel injector to fully open and close due to
the calculated short pulse width necessary hit this fuel target. Larger fuel injectors need a minimum
injector pulse width in order to fully open and close; if the motor is idling too low then the pulse width
may be too short to allow the injector to work properly, and an occasional miss-fire may occur.
If your idle RPM or AFR at idle has a slight fluctuation then you may need to modify your MAF
calibration table settings around the MAF voltage the vehicle idles. We have found that the stock
calibration settings at idle can be too far apart and they may need to be adjusted so the grams/sec values
are closer together at the MAF voltage where the vehicle idles.