I posted almost the exact same question in the General Tech forum yesterday.
http://www.turbobuick.com/forums/sho...threadid=11537
I have an OTC 2000 and Casper's Audible Knock Indicator. I am seeing up to 14° on the OTC, all occuring at shifts. The Knock Indicator never goes off while driving.
I thought maybe it had something to do with the OTC going thru the ALDL which updates slowly, while other tools connect directly to the ECM for real time data. (The Gauge/Audible would be real time since are connected befoer the ECM.) But someone mentioned the ScanMaster goes thru the ALDL as well, so I guess this isn't it.
Thanks Dave, it's good to know the OTC's are reading differently than others.