Those of you who are intimately familiar with the Maxima engine management, please comment on the following thought:

Once the knock sensor is defective, the ECU should run in the "safe" mode: assuming that engine knock is always present, and thus changing the timing to minimize knock. In other words, the ECU is programmed to run the lowest octane gas.

So, if your knock sensor is defective, and you choose not to replace it, you can use cheap gas without hurting your engine?

Any flaw in the above logic?

Thanks guys.

 

Well if your knocksensor is defective I would imagine that your ECU would make your engine run pretty rich. Also if you run lower octane gas it will prolly cause some damage to your o2 sensors. I would say you need to get a new knock sensor for $90 of ebay (where all the people get it) and avoid any other serious damage.

 

The O2 sensors will help the ECU to use the correct air/fuel ratio. A bad sensor only affect ignition timing advance (or the lack of it). If you don't hear any knocking, I guess it's ok. However, keep in mind that the engine is running in open loop with a bad KS, thus if the engine is knocking for any reason (hot temperature, bad gas, carbon deposit, etc.), it won't know thus your engine can be damaged. You really need to change the KS, though. Otherwise, you will miss out the engine power.

 

Since it's running in open loop, it's already running at the most conservative timing. So it's just the same as having a good KS operating in the worst situation (hot temp, bad gas, carbon deposit ...) right???