Base Idle - What are you setting it at?

[finestjammy]

Hi

I adjusted my base idle using the method in the bible, clamp the air intake to the stepper and adjust to 400-500rpm. I had a trawl on the postings here and noted that others are adjusting to 6,7 or even 800rpm. Any reason why others are going against the advice in the bible?

Thanks.

[blitzracing]

The base idle is simply the lowest setting the engine tick over at. The stepper then adds extra air to keep it at 800 to 1000 rpm dependent on the ECU chip used. If you wind up the base idle to say 1000 rpm, and the ECU chip is set for 800 rpm, the stepper will try and shut the airflow down to reach this, but cant. This can cause the ECU to throw a stepper motor fault code, but nothing more, and the ECU will still function as it should. Ive seen a couple of cases where messing around with too low a base idle seems to make the engine run a bit rich, but nothing is that critical.