Holly HP EFI-- Idle & IAC Tuning

[Glenn Briglio]

Originally Posted by Signman

Thank You for that Robin.
Been saying the same years.
People have asked me what AFR I run. Usually turn the conversation to asking where their O2 sensor is located and why optimum AFR may be different due to location if simultaneously recorded. Then go on to explain how fresh air is sucked into the collector. At low RPM fresh air influences the sensor even when located in the primary tube.
Not always easy to wrap your head around this stuff but once understood opens a lot of doors of understanding.

Use open loop at idle then go to closed loop after 2000 rpm