Does an Engine Need a Knock Sensor ?

[Katmandu]

Yea, I know...it detects pre-ignition/detonation signaling the PCM to pull (retard) the engine's timing.

But, does a knock sensor HAVE to be hooked up for the engine to run normally otherwise ?

The issue is with my winter beater (99 Blazer). It recently spun a rod bearing and I'm needing to put a used engine in. I found some newer/low mileage engines, but the knock sensors are completely different.

[mikedamufflr]

dosent the knock sensor just unscrew

[2007ShelbyCobra]

i bet it would trigger a trouble code without out,, but still run maybe..

[Ranger50]

You should be able to swap them or put on a new connector for the new sensor. But you will need it. You will either have a CEL or a CEL and reduced power mode until fixed. Your choice.

Brian

[Katmandu]

You should be able to swap them or put on a new connector for the new sensor. But you will need it. You will either have a CEL or a CEL and reduced power mode until fixed. Your choice.That's what I'm trying to determine if it will decrease engine performance without it. OR does it just retard the timing when pre-ignition is detected.

BTW, the (2) sensors are completely different between the model years I'm dealing with. One is a simple screw in with (1) wire the other is a bolt down (thru the center) with (2) wires. Competely different.

I "may" end up having to tap a boss in the block to accept the original knock sensor. :confused:

[Big J Botang]

I know on toyotas pickups they will cause the computer to retard power to prevent engine damage if the sensor is bad, it makes the ECU think there is a problem.