Spark knock? Really?

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Crunchtime2k

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Just put an entire tank of 93 and still getting the spark knock sound. . also. repeated the test in 4A and was identical. if in sport mode sometimes pinging will continue after letting off if trans is holding onto the gear. Its faint but noticeable at 5000 plus rpm and around 60 mph.




I had a 2018 and 2020 with a Cobb tune that does that exact same noise at the same rpm band, I just like you suspected knock however monitoring the knock detected values show no knock.

I still get that sound to this day with the Cobb tune...

and yes you can run 87 if needed , you will loose a bit of performance but the pcm will keep knock to a minimum , you need to monitor the knock PIDs. This will tell you what is going on.
 

Donmatteo

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Just put an entire tank of 93 and still getting the spark knock sound. . also. repeated the test in 4A and was identical. if in sport mode sometimes pinging will continue after letting off if trans is holding onto the gear. Its faint but noticeable at 5000 plus rpm and around 60 mph.


It will take more than one tank and 10 miles (assuming you just did a quick test) for the computer to relearn with the higher octane I believe.
 

Crunchtime2k

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Correct , i did do a Quick tester. i'll give it more time and give COBB a call. Thanks again everyone.
So you are running a cobb tune? why didnt you say so.


Please tell me your not running a stage 2 tune without a FMIC , this will cause weird knock issues also even if temps are low due to airflow restrictions.
 
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Anthony Palazzolo
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No, the truck was purchased used and one of the theory's was that it had been tuned. the odd thing is that I thought spark knock usually presents itself as soon as you step on it ... this happens at the top of the rpm range.
 

Crunchtime2k

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No, the truck was purchased used and one of the theory's was that it had been tuned. the odd thing is that I thought spark knock usually presents itself as soon as you step on it ... this happens at the top of the rpm range.


How much boost are you seeing? can you get a laptop with forscan to monitor it? that should hint if its tuned or not
 
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