Knock sensor - wanna see one?

[repiv]

Oops! Title should read KNOCK sensor.

For anyone who might be remotely interested, here is what the knock sensor looks like for a year 2000 Honda S2000:
http://thumb15.webshots.net/t/57/657/3/64/37/2324364370025981935uaHVVA_th.jpg (http://rides.webshots.com/photo/2324364370025981935uaHVVA)

Here's what a broken one looks like so you can see the insides (good one on left):
http://thumb15.webshots.net/t/57/757/2/23/13/2710223130025981935Hxdgve_th.jpg (http://rides.webshots.com/photo/2710223130025981935Hxdgve)
http://thumb15.webshots.net/t/57/657/7/35/48/2277735480025981935FslTkT_th.jpg (http://rides.webshots.com/photo/2277735480025981935FslTkT)

On an S2000, it goes here:
http://thumb15.webshots.net/t/58/158/8/8/36/2175808360025981935JOEwPU_th.jpg (http://rides.webshots.com/photo/2175808360025981935JOEwPU)

This is looking from the front of the engine towards the firewall and under the intake manifold. You can only see it and access it with the belt tensioner, tensioner mount and intake manifold brace removed. The sensor itself takes a 24mm deep socket, but it is impossible to get one into that location due to all the hoses and wiring harnesses in the way. I used a shallow socket to remove the broken one. To install it, I used permanent (red) Loctite and screwed it in as hard as I could hand tight.
This particular part number is used on year 2000 to 2005. In 2006 and 2007, the part changed. A knock sensor is designed to match a given engine AND to match a given ECU (computer). It must be able to tell the normal vibrations inherent in all engines and only take note of vibrations caused by "knock", like when the timing is too severe for the given load or for the given octane of fuel being used. The ECU then backs off timing to prevent knocking, which can destroy an engine over a short period of time.
Knock sensors are not necessarily interchangeable between engines of the same manufacturer or even engines within the same model line.

[Jesuis]

Did the old one stop working? How did you know, CEL?

I've always wondered, does the ECU throw a specific CEL code whenever detonation is detected?
I ask because I will be shipping my S to Europe next month, and I don't know what RON octane will be sufficient for my USDM tuned engine.
With Dutch gas prices as high as they are, I'd like to experiment with the different ratings, but I'd need to know if a specific rating is is causing my ECU to downtune.
If I can count on a CEL being thrown whenever the ECU decides to compensate for lower octane, it'll be easy to find out what the lowest (cheapest) acceptable RON octane is.

[repiv]

Did the old one stop working? How did you know, CEL?

I've always wondered, does the ECU throw a specific CEL code whenever detonation is detected?
I ask because I will be shipping my S to Europe next month, and I don't know what RON octane will be sufficient for my USDM tuned engine.
With Dutch gas prices as high as they are, I'd like to experiment with the different ratings, but I'd need to know if a specific rating is is causing my ECU to downtune.
If I can count on a CEL being thrown whenever the ECU decides to compensate for lower octane, it'll be easy to find out what the lowest (cheapest) acceptable RON octane is.

No, actually I broke mine in the process of putting in a new transmission and clutch kit. (Oh, and no, I didn't break my tranny either. I put in an AP2 tranny.)
A CEL light for the knock sensor would give you a P0325 or P0323.

[S2K_Randy]

Oops! Title should read KNOCK sensor.

Changed the title for ya :thumbsup:

[Stratocaster]

Costly little sensors aren't they? How did you break it? I broke one swapping from block to block. I guess the plastic drys out over time. Took no effort at all to break the one I did.

[griffon]

Did the old one stop working? How did you know, CEL?

I've always wondered, does the ECU throw a specific CEL code whenever detonation is detected?
I ask because I will be shipping my S to Europe next month, and I don't know what RON octane will be sufficient for my USDM tuned engine.
With Dutch gas prices as high as they are, I'd like to experiment with the different ratings, but I'd need to know if a specific rating is is causing my ECU to downtune.
If I can count on a CEL being thrown whenever the ECU decides to compensate for lower octane, it'll be easy to find out what the lowest (cheapest) acceptable RON octane is.

No one here wants to buy the old oil burner with bad brakes, huh.:D

How come you're leaving, Erik?

[repiv]

Costly little sensors aren't they? How did you break it? I broke one swapping from block to block. I guess the plastic drys out over time. Took no effort at all to break the one I did.

I finally did my tranny swap and clutch job. When trying to take out the elusive top starter bolt, the extension bowed so bad, it pushed up against the sensor and cracked the plastic body. At the same time, I punctured a coolant line as the bowing extension pinched the hose against a sharp clamp. I'll be doing a "How To" soon about this whole tranny/clutch change where I'll add to, ammend and put cautionary notes on the commonly accepted procedure. There are things that can be done far better, easier and safer and some things that don't need to be done at all.

[fperra]

I finally did my tranny swap and clutch job.

Its about time.

[Ben-KTR]

knock sensors are sensitive to torque, hand tight is not going to work you need to install it at the specified torque or it will read the wrong frequency.

[bish79]

I did the exact same thing to my knock sensor when I changed my clutch and flywheel. I found it easier to get to the sensor from under the car (actually I had a pretty clear shot at it if I remember correctly). And by the way, if anyone does know of a really good "easy" way to get that top starter bolt out PLEASE let us know.

[repiv]

knock sensors are sensitive to torque, hand tight is not going to work you need to install it at the specified torque or it will read the wrong frequency.

There's no way anyone's going to get a deep socket on that knock sensor and a torque wrench to tighten it without completely dismantling the intake manifold and removing from the engine.

[repiv]

And by the way, if anyone does know of a really good "easy" way to get that top starter bolt out PLEASE let us know.

I did a complete thread (with pictures) on the clutch job in the "How To" forum. I outlined a far better way to get that top starter bolt out.

[repiv]

Its about time.

What can I say. I didn't really need a new tranny or clutch over the winter, so I kept procrastinating. I sort of saw spring coming around the corner and got motivated. ;)