I know I know, another knock sensor thread.

It appears people have had good luck with these cheap KS.

My concern is if it they were junk but had a resistor to always return an 'in spec' voltage, keeping the code away, but wouldn't actually save your engine in the case of knocking.

Or, does the ECU constantly try to advance timing when the KS is working, meaning if it was bogus you'd be getting detonation right away as the timing advances past the point of knocking and the internet and this forum would be full of complaints of engine damage.

 

If everything is working right, you don't need a knock sensor. The ECU will only advance the spark timing so far, based on design limits. The knock sensor is there to "sense" the engine is not running correctly and let the ECU know it needs to retard the timing.

Using a resistor in place of the knock sensor would never do anything positive. If the engine starts knocking, the ECU would never retard the timing, therefore opening up the possibility of damage.

But why are you replacing the knock sensor? Unless the plastic cap is broken, the knock sensor is good. If your check engine light is on, you have other problems. And those problems cause the engine to knock which then causes the P0325 code. Fix the other problems and the knock sensor code goes away.

 

All other codes have been fixed and now only the knock sensor 'ghost' code remains, so it appears it is legit.

 

I read somewhere, it is a yes. The intent is to maximize fuel economy of a gas engine. In that context, gas engine has concept of load and timing is advanced to increase the engine power to handle the load while using the same amount of fuel and while it operates within a safe limit. Hook up an OBD scanner capable of showing live load & timing advance, you will see those parameters working along. You will feel better response when you start driving from stop, up to 30-40 mph.

Those ebay sensors may not be knock-off after all. Nissan could have contracted with third-party supplier/distributors (very cheap place to make) to supply the replacement parts for their cars. Perhaps, the contract agreement expired after 20 years. Now these places can sell them on their own for little profits.

 

I've found new OEM Knock Sensors on eBay for under $40 many times over the years. Also, if I can snag an Intermotor for the same price I will buy it also -- but those often cost more than OEM. I've used eBay knock sensor wiring harnesses over the years without issue.

 

alright thanks, sounds like they're legit.