I checked it with my ohm meter and got nothing a completly open circuit is this normal for a dead one?

The haynes manual said to use a 10mega ohm ohmmeter and Mine is only goes to 2000k ohm shold it of read something?

remind me does 1000k = 1mega ???

 

I wouldn't recommend hooking up an ohm meter to the knock sensor if it isn't capable of reading the high ohms. The knock sensor is a very high ohm output sensor. This could definitely shorten out your multi-meter. You may not get a reading because of this.

 

Mega = 10^6, so yes, 1000k.

 

I checked it with a 10Mohm meter and still nothing.

 

I believe they short out when they go bad. Your measurement of 10Meg or higher indicates the sensor is good. Are you getting the KS code? If your not, don't replace it - there's nothing wrong with it.

 

Ohm meters will not be damaged by checking a knock sensor.

Holding the leads apart, with nothing connecting them is subjecting them to infinite resistance. Touching the leads together will read zero resistance. Anything in between is fair game. Simply measuring the resistance of any 'non-live' circuit will not damage an ohm meter.

What does the book say about what is good or bad? I'm assuming the unit is a simple switch that is either normally open (infinite resistance) or normally closed (zero resistance)... and when it goes bad, it either sticks in one positon or the other.

If it was stuck in the 'activated' mode, the car would always run with the timing retarded, which would reduce power and make it suck gas.

If it was stuck in the 'non activated' mode, the engine would knock and ping when lower octane fuel was used.

Good Luck!

 

it has infinite resistance as in you get the same reading as if the leads were not touching each other.

 

Is that the resistance when you touch the two connector pins? I think that is normal, but I'm not absolutely sure. To be certain, though, what you want to do is put one lead on the left pin and the other lead on the metal base of the KS. If you have anything other than about 550 kohms then get a new KS.

 

The KS isn't a switch with open or closed positions, nor is it a variable resistor. It produces a frequency which the ECU reads.

 

Well, sort of. It is a piezoelectric device and creates voltage spikes under shock loading, such as when detonation occurs. If the voltage spikes are persistent (maybe at a particular frequency or frequency range) then the ECU retards the timing.

 

Thank you for clearing that up Stephen!