what does the knock sensor control? where is it at? and how often should you replace it? i know my cars has never been replaced and it has 101k miles on it.

 

The knock sensor detects "pinging" in the engine. Usually pinging is caused by poor gas and timing which is too far advanced (there are other things that cause it as well, but these are to most common). If you have never heard pinging before (or not sure if you have), think back to riding or driving a pre-80's car and step on the gas hard. It actually sounds like a knocking inside the enigne.

When the knock sensor detects a ping (or pinging) the computer will then back off (retard) the timing so that there is no ping.

In severe situations, repeated pinging can cause damage to a piston.

The knock sensor is located on the right side of the block just above the oil pan rail about 2" from the dip stip tube. It's white (or actually off-white) with an off-white connector going to it. If and when you do remove this sensor, be sure to drain your cooliant first and still have a pan under the sensor as it is screwed into the lower cooliant drain on the block.

Mike

 

so if i dont hear any pinging then i shouldnt mess with it? oh by the way ive never been a car older than mine before

 

If you're not hearing any pings, that's at least a good sign that the sensor is working. However, and this is for an example only, maybe the knock sensor is bad AS WELL AS the EST (Electronic Spark Timing). If the EST is bad (not saying so in your case, but again only as an example) the computer would not advanced your timing to begin with... thus, no ping. Granted, you would have other indications such as hesitations, poor performance, etc...

If you can, use the WinALDL. This program will show you if the computer is detecting pings, thus indicating the sensor is functioning normally.

 

when my fuel pump was going out i kept getting EST codes but soon as i fixed the pump they stopped

 

If the EST code stopped w/ the fuel pump fix, then the sensor is probably working. The sensor listens for detonation(engine ping) and stops this by retarding the timing. Its located near the oil pan and can be tested by quickly rapping on the engine block and observing the timing while at a fast idle. The timing should momentarily retard during this.