Why is only 1 cylinder knocking so bad!?!

FlashPro questions & answers specific to the 2006-2011 Americas Civic Si
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tec_neak
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Joined: Mon Apr 09, 2012 3:17 pm

Why is only 1 cylinder knocking so bad!?!

Post by tec_neak »

Let me start off with my mod, Injen cai and flashpro. Everything else is completely stock and the car is just reaching 40,000 miles.

So this log was taken from a 1hour and 30min drive. The problem is obviously knock, but it is only happening in cylinder 4 and it is happening at a very rapid pace. It is hard to reproduce this problem it only happens in 1 out of 4 logs that I take. I notice that it happens when I am at a constant load in 6th gear, mainly around 65 to 66mph. I have tried flashing back to a base calibration but knock still occurs. Which lead me to think it was a mechanical problem. I have also tried changing the spark plug, running injector cleaner, but that specific case still occurs. Im not sure if it is the tune, or if it is a mechanically problem. I also attached a picture of the ignition map, is there anything wrong with it?

Any input on this would be greatly appreciated!!!
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Hondata
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Re: Why is only 1 cylinder knocking so bad!?!

Post by Hondata »

Try the AFM calibration as it has ignition timing closed to stock.

Reduce the ignition timing for all cam angles by 2 degrees. If the knock decreases, then it is over-advanced. If not, then it is mechanical noise. Exhaust systems & engine mounts can cause this - sometimes just a loose bracket in the engine bay hitting the engine. You could also decrease the ignition timing just for cylinder #4 by 2 degrees to see if that helps.
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tec_neak
Posts: 2
Joined: Mon Apr 09, 2012 3:17 pm

Re: Why is only 1 cylinder knocking so bad!?!

Post by tec_neak »

Thanks for the reply, currently I have parts of the ignition map that was effect by the knock retarded by 1 degree. I'll continue to keep collecting logs until I the problem is reproduced again and see if there is a difference. If there is I will degrees the affected areas by another degree to see if it helps. Since the knock doesn't happen every single time this process is going to take a while until it can be reproduced.

And you said simple things like a loose bracket could cause knock, what about noisy valves? Is it possible that if I adjust the valve lash the knock would go away? I do hear a ticking coming from the head but Im pretty sure the ticking is coming from the injectors but I could be wrong.
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