My car is getting knock retard. Its getting anywhere from 1-3° at idle, but once I accelerate a bit(1500rpm), the knock goes away. Once I pass about 3000-3500rpm's, it comes back and shoots all over the place (4-12°). I already put in, 5 gallons of 100octane race fuel, into my 1/2 of 91 octane. The knock is still there. Do you think this is false knock? There is no relatively loud noises, or banging, other than the movement of my cam in the motor, or perhaps my headers.

Any possibility that it could be the knock sensor? A friend of mine's car shot a code when his sensor went bad, is this always the case? Does the knock sensor usually just fail when it does, or progressively get worse? I have not desensitized the sensor, because I dont know if that should be my next step, or should I try and replace the knock sensor first. I do not have a code for mine. I already measured the sensor, and it gave me a reading of 16.9k ohms. Also I recently deleted my EGR system, and have not tuned it out, can this be the cause? Any advice or suggestions would be greatly appreciated.

 

First of all, don't just ask for one or two persons responses. You'll turn away a lot of people that might know about your situation.

Second, do you have the LT4 knock module? That will make a huge difference in your knock counts, especially if you are cammed with headers. Headers will amplify valvetrain noises and frequencies, and can be interpreted as false knock. If the knock sensor wasn't working, you would receive an SES light and the PCM would retard timing to prevent any unknown detonation.

 

If you have tried 100 octane and the knock is still there. It would be safe to say its false knock. Usually from headers or from something hitting the kmember. I would get some heat wrap and try that.

 

I didnt mean only Shoebox or Injuneer could respond, just that they are extremely knowledgable, and have helped me out in the past. Didnt mean to turn others away. Yes, I do have the lt4 km.

 

16.9k ohms is not a good reading for the knock sensor. An OBD-I sensor should read 3300-4500 ohms. I would replace the sensor.

I agree, that it is best not to call out people by name. Much better chance that your post will be ignored by everyone else.

 

I retested, I had it on the wrong setting, it gave me 3.87

my multimeter has various settings for testing ohms, which should I be using?

200
2k
20k
200k
2m

What I am doing is puncturing the wire off the knock sensor with the + side of the multimeter, and grounding the - of the multimeter. All of this was done on the 20k setting with the key off, is this right?

 

You can usually test a knock sensor to see if it is working by using a hammer to give some taps to a solid part of the engine block or bracket. The counts should be seen by a scan tool or data logger.

There should not be any knock at idle (something physically knocking could do it, though).

 

Ok so I tested the sensor, and the PCM occording to the Chiltons manual, and everything is right on. Should I go ahead and desensitize?

 

I wouldn't before making the test I stated above to see if the sensor is actually working.

 

do you think it could be my large cam causing the motor to shake quite a bit?

 

I know this wasn't directed towards myself. Have you changed your motor mounts out at all?

 

no they are stock motor mounts....

 

ttt anyone?