IAC-Idle Map threshold vs RPM

[muttley383]

Hi, just an enquiry on what the IAC-Idle Map Threshold vs RPM parameter should be set at.

If the engine is idling at 800rpm with a Map of 40kpa, should the IAC-Idle Map Threshold table be adjusted to just above 40kpa @ 800rpm to enable correct idle control ?.

I am using the OSE_12P if it makes any difference.
Thanks in advance for any replies.

[VL400]

Yeah the settings should be so the actual idle MAP is below the table. If the idle MAP exceeds the table a few steps are added to the IAC to aid in throttle crack and TPS following, would also mean a high idle if not set correctly. When the MAP is below the table value it then looks at TPS for throttle crack to initiate the throttle follower (the way the RPM hangs high for a few seconds after giving the throttle a hit).

So the items at play are...
First - IAC - Max Idle MAP Vs RPM
If MAP > table - Transient IAC params - MAP Limiter Gain Factor
If MAP < table - Transient IAC params - Throttle Crack Delta TPS
If TPS > throttle crack TPS - Throttle crack offset Vs RPM
And then after throttle crack - Transient IAC params - Throttle Crack Decay Rate

[Holden202T]

When the MAP is below the table value it then looks at TPS for throttle crack to initiate the throttle follower (the way the RPM hangs high for a few seconds after giving the throttle a hit).

Always wondered about that!

[muttley383]

Thanks for the reply, trying to make sense of the parameters.