Reading Message 0, Word 52 (Knock Retard) from the ECM

engineermike
10-02-2005, 10:45 PM
Me and a friend are building a hand-held ECM scanner with WBO2 and 3-bar MAP inputs with logging capabilities.

We're having problems reading knock retard, though. The data line in Word "0" is supposed to be:

52 GP6ENOCK KNOCK RETARD
DEGREES = N/2

However, the output is around 20 degrees at idle, 30 degrees at full throttle, and 0 in the middle. Max in my TunerCAT file is 16 degrees, so these numbers can't be correct. I think it's odd that "degrees = n/2" allows a number up to 255/2, or 128 degrees when the knock retard stays under 20 degrees.

Anybody have any idea what I'm doing wrong? What's the correct formula?

Thanks,
Mike

engineermike
10-03-2005, 09:34 PM
Okay, we figured it out today. Get this, with manual cars, knock retard is N/2, but with automatics, it's N/16. My buddy set it up for a manual since I have my auto functions disabled (TH350).

Mike