knock detection
 

just curious... I haven't seen any mention of engine knock sensors in the workshop manual.

Do any of you know what the 944 does for knock detection? Is the sensor narrowband, and if so, what is the cutoff frequency? Also, where on the block is it located?

Since I have an early '85 car, I'm more interested in what they did on that one, but if you know what goes on in the later models, feel free to share.

The car doesn't have them (at least I am 95% positive it doesn't). All fuel/air mix, timing etc is controled by the DME. It makes adjustments on the fly to prevent knocking.

AFJuvat

hmm... I wonder how much more agressive the timing could be if the fuel injection used a knock sensor. Seems like the car would be more tolerant of different grades of gas, etc.

*sigh* I gotta stop reading this forum because it only leads to "how can I make my car faster" daydreaming...

I have a book on fine tuning and diagnosing Bosche injection systems, and I do recall something about a knock sensor. I'll dive back into it and give ya a yell back

Actually the timing and reference sensors take care of knock detection.

AFJuvat

There most definatly is a knock sensor on the 951/968 (LATER 944?). Located on top left side of the block right next to the cyl head b/n cyl 2 & 3 under the intake. 1 VOLT

...as in, the DME notices that the timing pulse is later than expected?

anyone know how to hook a light up to it to see when its knocking?

on a 951