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I'm seeing knock counts between 2 and 7 thousand when i start my car (95 Firebird Formula A4), the count doesn't go up any more after the engine catches and is just idling though.
I'm not sure if this is normal or if it is going to be causing issues with how the PCM is trying to fuel/time the engine seeing all the knock. Do i need to get the KS desensitized?
Knock count is cumulative and the PCM makes it happen on purpose at start to verify the system. Worry about it if it is actively rising while driving or if it is causing a lot of knock retard.
The pcm tests the octane of the fuel on startup by cranking in a lot of advance and determines which spark table to use from the results. Normal operation.
The pcm tests the octane of the fuel on startup by cranking in a lot of advance and determines which spark table to use from the results. Normal operation.
It's false knock caused by the starter contacting the flywheel/flexplate. It's totally normal. If the computer ramped up the advance on start-up, you'd have a broken starter or nasty backfire. Knock sensors basically detect noise and when the teeth on the starter and the flywheel contact they create a lot of noise that is sent through the block and is picked up as knock. The only knock you need to worry about is while the car is running, start-up and when turning off the engine are irrelevant to the performance of the car.
10-03-2014, 04:05 PM
High knock count on startup 
