How does it actually work? Is it just like a microphone, and literally hears the sound? Or is there something more sophisticated?

 

well.. lets see here. a knock sensor does wat its called. it senses pings or knocks when the spark plugs are firing in the cylinders. when the A/F is being compressed and the piston is going up.. the mixture is heated up till it reaches TDC then the spark plug is fired.. now.. here is how the knock works. when the piston is moving toward TDC and the mixture prematurely ignites.. as in.. it combusts before the piston is all the way up.. the knock sensor senses that the combustion of the mixture was too early. so it sends the info to the ECU telling it to retard the timing becuz the cylinder fired early so it thinks that the ignition timing is too advanced. now when the timing is retarded.. your knock sensor light will come on. .then your acceleration will suck ***. the knock sensor senses pulses from the cylinders. if the pulses are abnormal.. then itll send the info back and forth to see if anything wit the ignition is wrong. then it will try to correct it. its all magnetic pulses. interesting how they work huh? NEVER USE CHEAP GAS.. use onlie higher octane .. knock sensors are cool hahaha hope that helps you doode..

DiZ

 

sigh

I think I should write a knock sensor FAQ. That isn't what knock is, knock detection does not light the SES, a failed knock sensor does not light the SES, and the spark is fired well in advance of the piston reaching TDC.

 

you did already

http://forums.maxima.org/showpost.ph...3&postcount=42

BOOKMARK IT EVERYONE!!!

 

hater... haha sike.. well knock is pre ignition in the cylinder.. knock or ping is the same ****.. when the mixture is prematurely ignited then ignited at the right time.. the sensor feels the pulse.. that the cylinder fired twice which is not normal..

jus wanted to put it out there as in general.. not jus the maxima.. jus sayin that a bad knock sensor will retard timing.. knock sensor jus detects abnormal firing in the cylinders..

 

I'm not asking WHAT it does. I know what it does. I'm asking how it does it. HOW does the knock sensor detect knock? Dizmax said it feels the pulse? There's some sort of shock sensor in there? Would it be possible to set off the knock sensor just by literally knocking on the engine block, with say, a rubber mallet or something?

 

yes it can. it senses knocks by pulses. you can test the knock sensor by tapping the engine wit a rubber mallet. it senses vibrations in the engine. and outside interference.. like tapping the engine.. the knock sensor will detect that.

yeh the knock sensor can feel the vibration of the combustion in the cylinders. and the vibration from a rubber mallet if your gonna tap the engine..