My knock sensor is acting up. I know that many others have had to replace their knock sensors as well (bad design). So here's my question, on a NA car, is a knock sensor necessary? or could we replace it with a resistor or some circut to simulate it?

Discuss.

Discuss.

Is this a homework assignment?

The sensor will, through the miracle of the ECU, retard the spark if you get low octane or otherwise poor gas. Yes, you need it.

Case and point. (http://forums.nasioc.com/forums/showthread.php?t=707761)

Basically, it is a fail safe device that will help your engine in the event of something really bad. Personally, I'd keep it or adjust it and add a J&S Safegaurd to keep better tabs on things.

AJ

I was fed up with mine for about basically 8 months when I finally replaced it with some earned cash and MAN does it feel better to have some POWER!!!

I would have got to pay $101 JUST for a knock sensor at the STEALERSHIP!! SO I went to another dealership where I get discount for being a member of our local group. Totaled out to be $85.xx with the discount. The price WAS $84.xx to begin with, I dont' know WHY or HOW the first dealership charges SO much. NO MORE going to THAT dealership, although I DID buy my car from them...

Do you need it? No. Is it a very, very good idea to have it? Yes. Subarus run pretty high compression ratios for an engine designed to run on 87 octane. It's the magic of the modern ECU (with things like knock sensors and very smart adaptive engine management) that allows the engine to run safely.

Pat Olsen
'97 Legacy 2.5GT sedan

If you remove the knock sensor altogether the car will run in open loop all the time, as well as likely throw a code. Open loop means it will run fairly rich all the time, which is not usually a good thing. Your fuel economy will drop and you will likely lose power.

If you remove the knock sensor altogether the car will run in open loop all the time, as well as likely throw a code. Open loop means it will run fairly rich all the time, which is not usually a good thing. Your fuel economy will drop and you will likely lose power.
I know that, which is why I suggested the resistor.

I would have to agree with needing the knock sensor. I recently fried mine. The wire on the knock sensor was apparently rubbing against the radiator hose that feeds into the throttle body and eventually wore the insulation for the knock sensor away. This caused the radiator hose to melt and split the wire in half. Though only drove 2 miles to get a new knock sesor after that the car ran like complete crap on the way to the dealer. You definitly need it. If you replace it though be sure due to bad design to watch for the radiator hose, I actually wrapped my knock sensor wire it 1/4 inch hose to prevent the same problem I already had