High RPM at initial start up

David Claflin · Post by **David Claflin** » Sun Feb 17, 2008 5:40 pm

When I first crank the car, especially when cold it runs up to about 1800 RPM for a second and then the idle settles down to normal. Is there a function/scaler I can tinker with that will tame this down a little??
I'm sure my neighbors would appreciate it at 5AM every morning.

Post by **dex** » Mon Feb 18, 2008 3:02 am

There are the following parameters that may be affecting your high startup idle rpm;

'Idle Startup Adder' (aka FN826A)
'Buzz RPM' (aka BZZRPM)
'Idle Adder for ACT' (aka FN825B)
'Idle Adder for ECT (aka FN825A)

David Claflin · Post by **David Claflin** » Mon Feb 18, 2008 10:15 am

Thanks, I had found all of those, but didn't know of buzz RPM. The most any of those boost RPM is something like 48 RPM.
If the TB airflow was off would that cause this issue? I have a 75MM and have TB airflow to .95.

Post by **dex** » Mon Feb 18, 2008 12:13 pm

The idle adders are often cumulative so this can add quite a bit of rpm above normal idle speed. The stock A9L 'Idle Startup Adder' (aka FN826A) adds 432 rpm around 76 deg F ECT and I wouldn't be surprised if the rpm overshoots it's mark at startup when trying to add a lot of rpm.

If your TB airflow value is off then it can cause idling problems if the adaptive learning doesn't cope but I'm not sure if would show itself as a brief startup issue.

David Claflin · Post by **David Claflin** » Mon Feb 18, 2008 1:02 pm

I took the idle start up adder to 0 already and am going to lower some of these others to see what that does. Thanks!!