My car has started throwing the SES light, hooked up scan tool, it reads the code for "knock sensor/spark circuit failure", I believe, sitting here at the computer, that it was code 42 or 43, but its the one the scan tool and book show as the title mentioned above. I talked to Brian Herter (PCMforLess), and he suggested I replace the Knock Module, I tried that yesterday, but the car still has the code, which wont clear. The car also begins to go from running even air/fuel to extremely rich within a minute of starting up, and begins to run poorly/stumble a little. I checked the wire going to the actual block knock sensor, and it is attached, not broken or loose. The knock sensor is less than 6 months old, but I guess that could be the culprit. My knock sensor reading was "17" on the scan tool, which leads to my next question, is there a good site for scan tool/pcm readers that has a good break out and explanation of sensor readings/codes ect for F-body's, I remember one guy did have a good site that showed and explained what should be normal/abnormal readings, and suggestions for trouble shooting.
Any suggestions as to what could be happening, this problem happened almost overnight, good running car to extremely bad?

Jon
95 Camaro Ultra Z - Supercharged LT4
96 Impala SS - Turbocharged/intercooled LT4'd
70 1/2 Camaro

 

If there is a fault in the knock sensor circuit like the PCM is reading, it will automatically pull timing, since the PCM does not know if any knock is present, as a safeguard. Your poor running condition can likely be from the PCM pulling timing. I'd double-check the knock circuit for any breaks that you can't see, and ultimately replace the sensor.

If the wiring is in good shape, it's probably the sensor. The KS circuit is pretty simple, and a problem should be easy to trace.

 

The code DTC 43 is for the knock sensor circuit. Typically, that is a faulty wire or a faulty sensor. Very easy to check:

Pull single wire off knock sensor, turn on key. Measure voltage between harness connector and block. Should read approx. 5V.

With wire still off sensor, measure resistance from single pin of sensor to block. Should read about 4,000ohms. (I assume you are talking about your OBD-I 1995)

Connect wire to sensor, key on. Probe from connector to block. Should read approx 2.5V.

That will tell you if the circuit components are OK.

What do you mean by "My knock sensor reading was "17" on the scan tool"? Not aware of the ability to read anything other than knock count, and 17 wouldn't be a typical value. Do you mean you were getting 17degrees when you scanned for knock retard?

You may be thinking of my ScanMaster writeup.

 

when scrolling down my Actron scan tool screen, it will display knock retard, which was Zero, but there is a knock sensor reading too, which only had "17" for a value, not sure what it means, thats why I was curious if anyone had a website that explained all scan tool readings.