Hey guys, about a week ago, my knock sensor went off after I swapped in a new motor into the s2000. I broke the old knock sensor when pulling the motor, so I ordered a new oem one, so it’s less than a month old. When driving to a meet, I did a pull, hit vtec, and a small puff of blue smoke came out (according to my friend), and a hissing noise started. I turned her off, coasted to the side of the highway, got her in the air and no visible leaks, damage, or anything. No oil loss, coolant looks fine, nothing out of the ordinary and she drives just fine besides a clattering noise that I hear past 48mph. She will still engage vtec, shift properly, go through the revs. The noise can’t be heard at standstill or idling, tested it by revving up to 6 and holding, and no noise. Seems to be a speed related thing and I believe it’s setting off my knock sensor. Any ideas?

 

You got no CEL codes?

Thanks!

 

Yep, as stated above, list the actual code you are seeing or what is leading you to think something is triggering the knock sensor. Unless something is actually slapping against the block, you have actual pinging going on, then it likely is not some other sound setting it off.

Does that sound continue if you depress the clutch and coast?

 

Code is P0325, circuit malfunction, bank 1
sound and engine noise are audibly separate
noise continues when clutch is pressed in, however it goes away after slowing down enough

 

so there is an issue with the knock sensor circuit... damaged wiring, etc. should be the first thing you check.

That sound is related to car vehicle speed. So likely not related to the motor at all.

Troubleshoot the knock sensor circuit.

 

Ran into this issue. I bought an NTK one. Garbage. Threw a code within the first 1000 miles.
Bought a new Honda one and it worked. No codes since.

 

I’ll take a look at it this weekend, and as for that off brand knock sensor, I had a shop order the part for me so it should be oem Honda. But any ideas as to what exactly that sound might be? It sounds like it’s related to the knock sensor since it’s coming from that area

 

By the way, instead of going to get my shop manual out and taking pictures I shamelessly stole the one @windhund116 posted in another thread about this code

 

That sound likely would not even trigger the knock sensor. The knock sensor is actually looking for pinging in the engine and sometimes something like an actual rod knock can set it off (but that is not what it is monitoring for). But that sound is quite different and should not be triggering it from how it sounds on the video. That sound is not related to engine rpm and is related to speed, so focus on things that are directly tied to speed. Aka anything rotating when the car is moving. It is hard to pinpoint exactly what that noise is from the video.

 

Correct. Knock sensor and camshaft position sensor should be working together and would throw misfire code, not knock sensor error malfunction. What you will notice though, however, is that you're burning/dumping a massive amount of fuel since the knock sensor is likely running off (rich?).

I'd probably look under the car and see if anything is trapped under there, that's pretty interesting. I'd feel pretty confident in betting it has almost nothing to do with the engine itself. (what's inside the engine). There could be stuff moving around in your engine bay.

I notice that it makes that noise even off throttle, so it could be anywhere under the car smacking a wheel spoke/moving part.