Quote:
Originally Posted by 2001hawk
Why your vehicle would not pull timing when the knock sensors detect detonation is NOT normal. Every GM vehicle I have seen lays down like a dog when the knock sensors tell the PCM. Usually 12 degrees of timing is pulled and that is noticeable. Some of the guys rely on the knock sensors to pull timing for there nitrous. It is a little strange because if the knock sensors had been tuned out at some point it shouldn't be able to set off your MIL.
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working knock sensors detect abnormal knock and send that information to the PCM to make changes to ignition timing. under these circumstances a code is not set.
knock sensor codes are set when the PCM does not get input from the knock sensor/s either because the sensor is bad or the circuit is bad.
there is no code for "too much knock".....
when my truck had a knock sensor "A" code i was wondering how much timing was dropped because of the code so i logged ignition timing, then replaced the sensors and harness and logged again. no change in ignition timing so i compared the numbers to the map and it was the same.
the PCM has the ability to advance the timing based on input from the knock sensors, i believe the PCM might not do this with a KS code, but Jaime would probably have a better understanding of this part. i've never looked at adaptive ignition, i tune for zero knock retard and then let the PCM do its own thing.