kinetica

I have searched and found that one person said thier S ran SLOW with a broken knock sensor, and another said his broken knock sensor caused a CEL.

Just for absolute verification:
1. Will a broken knock sensor make your ECU pull fuel or timing, hence running slow?

2. Will a broken knock sensor throw a CEL?

3. Does the ECU receive constant feedback from the knock sensor, or does the ECU only recognize it when it has knock?

4. Does it matter what MY it is?

Thanks.

kinetica

anyone?

SenderGreen

I'll look through the Helm's in a little while. I wish I knew the answers. Off the top of my head I would say yes to all four.

EDIT: I still haven't checked the Helm's, but I see 3 is not yes or no, so

1.) If it did I would think you would notice. I don't think it would do this without throwing a CEL.
2.) I would think so.
3.) I think this is a "continuous monitor".
4.) I don't understand, as far as the part itself (knock sensor) goes? Do you mean what the ECU is doing?

kinetica

Thanks for the input. About #4, someone told me that the ECU had constant feedback with the knock sensor starting with MY04. Wanted to find out if that was the truth.

SenderGreen

My Helm's only covers up to 03, but may provide some insight. I'll still have to check in a while. So 3 and 4 are kind of the same question. I think I got it.

EDIT: 2.) DTC P0325 (Knock Sensor Circuit Malfunction).

SenderGreen

It's funny because that is what a knock sensor that works does.
"The knock control system adjusts the ignition timing to minimize knock"

1.) Based on the info available to me I don't know if a broken knock sensor will put the car into "gimp" mode. From what I have read you would most likely notice if your car was in "gimp" mode. I think read something about it not letting go over 3000 or 4000 rpm. However this is from memory and I don't know for certain if there are different levels of "gimp" mode (I don't think so). Either way I doubt your car would be doing this without throwing a CEL.

2.) DTC P0325 (Knock Sensor Circuit Malfunction).

3.and4.) All I could really find is that if your knock sensor is broken you should have a CEL and the above DTC. When troubleshooting the above DTC the Helm's say's to reset the ECU, then start the engine and warm it up. At this point the if the DTC returns (sounds pretty continuous) they have check the resistance and continuity on the wiring harness. If that checks out, then they have you substitute a known good knock sensor for testing or replacement. So, I don't know if it is technically considered "continuous" like the misfire monitor, but it sounds like it is.

kinetica

Thanks sendergreen. Great Info.

radfox

I just broke my knock sensor on my Vortec SC'd MY02 and the CEL is on with the Knock Sensor Malfunction code. I soldered and epoxied it back together until the new one comes in, but it eventually CEL'd again. Funny thing is I don't see any ill effect of this. I checked timing while under WOT and I saw 22 degrees advance and I don't hear any pinging. 22 degrees would be normal timing on my turbo'd 4G63. I would think that with a broke sensor the timing should be pulled like mad. I'm wondering when these cars pull timing? I think I'm even getting the same gas millage.

Is this normal for this engine?

djpeak10

I am vortech supercharged and i broke a knock sensor in half, and I wasnt sure if it was running the same or not so when i put the new one on I knew for sure. when fixed it ran how it was suppose too, So i believe there are two types of gimp modes 1. that doesnt allow you to drive over 3k rpm that sucks been there done that and our car is almost impossible to drive like that 2. whith my broken knock sensor i noticed it mainly not pulling at the end of a gear as hard as normal. I have nothing to back this up except my experience. To sum up get a new knock sensor but til then you wont hurt anything driving around

Ek9

Most knock sensors are ineffective at WOT and above certain RPM's. Basically a knock sensor's a microphone tuned to certain frequencies. When the engines rev enough, they make enough normal noise in the "knock" freqency the sensor is looking for, they can't be depended on.

Read up on tuning an AEM EMS. There's tons of good information about this. Basically you depend on the sensor up to certain RPM's and then just guess when the mechanical noise overwhelms the sensor. So, if the ECU learns it needs to retard 5 degree's at 5K for instance, it'll interpolate at higher speeds.

One of the reasons I run 100 octane in my civic, is I know it's too loud to hear knock and I don't want to break a ring or blow a hole in the piston top (JDM Engine). My 2k's stock though so, I just depend on the ECU to do it's job and keep the timing in check.

Just keep in mind, when stuff breaks, it's mostly random so, there might be 50 different failure modes. I don't think you should depend on one person's experience with a bad K-sensor as gospel or anything.