Gary C2

Where are the knock sensors located on the engine? Are they on the top or bottom? Are they easily accesible?

Thanks!

Kevin

Gary;

They are located on top of your cylinder/liners, very close to the engine case, one sensor per bank. You can get to them by pulling out you alternator/fan assembly. The question is why do you need to get at them. ( just curious)

Jon 91 C2

See this diagram (its for a 993, but the 964 is identical). Item #5 is where the sensor attaches to the engine. Items #9 & 10 in this diagram are where the knock sensor wires pass through the fan shroud.

If you are interested in checking the knock sensors because your computer is reporting an error, you should clean the wiring connectors that lead to the sensors before you start digging into the engine.

My '91 C2 check engine light came on and the computer reported the knock sensor as having a problem. It turns out that the connectors had built up some corrosion and just needed to be cleaned.

There are two connectors on my C2, one is green and mounted on the front of the intake manifold. The other is on the left side of the engine hidden behind the heater blower motor.

Gary C2

I checked the two knock sensors and it appears that the right knock sensor is not functioning. Can the sensor be replaced by removing the fan assembly or does the shroud need to come off? BTW, I am experiencing hesitation and lack of power during acceleration.

Kevin

Gary, the shroud does not need to come off. Like Jon said, try cleaning the connection.

Bill Verburg

Knock sensor #5

Gary C2

Can anyone tell me the torque spec for the knock sensor bolt?

Thanks.

Bill Verburg

The M6 knock sensor bridge to cylinder bank bolts should be tightened to 9.7Nm(7ftlb)

The M6 knock sensor to knock sensor bridge bolts should be tightened to 20+-5Nm(15+-4ftlb)