Heavy Knock in 2nd gear, but almost none in 3rd and 4th gear

K-Series Programmable ECU installation questions / support issues
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anjapower
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Joined: Wed Oct 27, 2004 8:40 am

Heavy Knock in 2nd gear, but almost none in 3rd and 4th gear

Post by anjapower »

My setup is: k20a2 head, k20a3 block, AEM CAI, Comptech RH, Comptech Exhaust, Hondata IMG, Hondata Kpro.

My car has been tuned on a dyno and put down 197whp on a dynojet. Upon completion of the tune, everything was fine and dandy and it has been since. I noticed a few weeks later that the setting to flash the CEL upon knock had been conveniently turned off by my tuner.

I tuned on the CEL and did a few datalogs. In 3rd and 4th gear pulls, I get next to nothing for knocks, somewhere in the 0-3 range. However in 2nd gear, I get anywhere between 15-40 knocks. Any idea what could be causing this?

I am under the impression that the engine should knock more under a higher gear/a gear with more load. But I get knock in a lower gear, and none in a higher gear.

What could be causing this?

Here's a link I posted on Clubrsx about this:

http://forums.clubrsx.com/showthread.php?t=203771
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Hondata
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Post by Hondata »

The engine will run slightly differently in each gear, due to differences in thermal conditions and engine acceleration. Also be aware that the gas changes from summer to winter in early October and this often lowers the octane rating substantially.

You need to establish if the engine is actually knocking. Removed 2 degrees ignition everywhere and see what effect this has on the knock count. If the knock count stays the same or only changes slightly, then it is likely that other mechanical noise is causing the ECU to detect knock. If possible find a knock amplifier and use one to listen to the engine (HKS makes (or made) a knock amplifier).

If removing advance decreases the knock count, then reduce ignition advance in the areas where the ECU is detecting knock. You should get no knock count while datalogging.
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anjapower
Posts: 2
Joined: Wed Oct 27, 2004 8:40 am

Post by anjapower »

if you had to guess however, would you say it seems that its extra noise the knock sensor is picking up?

I understand why you're recommending the above but logic would only point towards extraneous information being recorded, no?
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