Yep, generally automotive sensors can be classified into tow categories, voltage gereating and voltage modifying.

Voltage generating sensors like your knock sensor create a voltage. As EPNCSU2006 said, the knock generates an electrical charge. Knock sensors operate with the same pricipals as the little red ignited button on your BBQ grill.

Voltage modifying sensors are fed a .5v signal from the computer, and depending upon how a condition or environment acts on the sensor, the resistance of the sensor changes. This resistance as per Ohm's Law then changes the voltage of the .5v refrence signal. The computer is programmed to understand what the differences in voltage mean. Good examples of these are throttle position, oxygen sensors, and mass air flow sensors.

 

Thanks for the info..... Should I wrap the sensor in good ole duct tape to prevent it from banging around and possibly sending false chatter to the computer?

 

That may not be nessisary, in order to get the sensor to provide a voltage while you are watching it on a good scanner, you have to smack the block near the sensor with a hammer.

 

Move the O2 sensor to the Voltage producing sensor list

 

Whoops, brainfart!! Man, it's been too long since i've been doing this kind of thing day in and day out. Yep, the EGOS use the differences in atmospheric composition between the air outside and in the exhaust stream to create a voltage. Thanks for catching that.

 

Trying to understand why I got a knock sensor code only on the koeo and 111s on the koer test. The koeo test seems to vary each time I test it and so far it's ranged from low a.c. refrigerant to fuel pump and now knock sensor. The symptoms are pointing to this but I'm tired and broke from throwing parts at this 94 explorer 4x4 4.0l pushrod v6 xlt. Any suggestions welcome I'm going to test that sensor if I can find it.

 

Posting in the correct forum might help....

Explorer, Sport Trac, Mountaineer & Aviator - Ford Truck Enthusiasts Forums