False knock readings?

[groundhogday1976]

My timing chain rattle is still present after removing the upper guide (although not as bad). Is it possible for the knock sensor to read the ticking as knock?

[NISTECH]

are you getting a knock code? usually the sensor goes bad. replace the sensor and the sub harness for the sensor to take care of the knock code.

[groundhogday1976]

I haven't checked for a code, I just wondered if something like that could happen.

[Q45tech]

The ecu is gated so that the knock sensor [microphone] is only open when real knock could occur---say 10-15 degrees every 90 degrees [on a V8], every 120 [V6] or 180 degrees [I4].

Also a filter only passes 5-8 KHz [exact frequency depends on bore diameter] that knock makes.

[groundhogday1976]

Thanks. Just wondering about that.

[Q45tech]

Easy to use a sound card/computer and inexpensive audio spectrum analyser software [free demos on inet] to see the knocks by sampling the KS line prior to ecu .............use a 0.001 uf and 1 megohm resistor is series to isolate the lap top and not load the line to ecu. As most sound cards are 600-1k ohm vs KS 550,000 ohm.

Stereo card lets you see/record 2 at a time [for V8].