Got code P0325 on my OBD-II scanner. That's the 0304 knock sensor code. Dealership said don't worry about it and said new knock sensor not required. I'm also getting a slight surging/hesisation at part-throttle.

I check codes at the end of every journey. I get the code 80% of the time, even on very short trips.


I tried the following to diagnose it;

- Disconnected the knock sensor. Timing raterded to safe level, car drove like crap.

- Tried a different brand of gas (shell, from BP). No effect.

- Tried Marathon gas. No effect.

- Tried Octane boost on top of my regular 93, to hopefully reduce knock. THinking that if this reduces/eliminates the knocksensor code then it could be carbon fouling in the cylinders. 2 bottles of 104 octane boost in the same tank - no effect.

- Tonight I'll try a 470k resistor across the harness. This should isolate the wiring only so any code would be related to the harness, not the sensor. Also, I'll listen to see if it pings.


Here's my next steps as I do the resistor test...

1) If it stops the code and there is no pinging then I'll replace the KS.

1.1) If I replace the KS and it's still bad, then I need to look for some other source of engine vibration that could be fooling the KS.

2) If the ping comes back but no code then I need to look at why the engine is pinging, poss carbon fouling.

3) If the code comes back then the harness is bad.

 

How did you alter the timing on a VQ30 that has a fixed timing sensor?

 

It's thought that disconnecting the KS (simulating a bad KS) will cause the ECU to limit ignition timing advance.

 

He said he did disconnect it and the timing was retarded. I am havin the same problem, let me knwo how it turns out.

 

there is no adjustment for the timing on the maxima

 

I know there is not adjustment - As I understand it, the computer will automatically retard the timing if it detects the KC circuit is open. Stops there from being any ping, but drives like crap.

 

Exactly, the ECU does the adjustment in timing, it is not done manually.