knock sensor replacement

[blackbeautysvx]

recently had some work done on my 97 LSI, the check engine light was on and the code indicate a knock sensor issue. however, the engine is running smooth not rough at all.

does anyone know what the common symptoms are if the knock sensor is failing? Is this a simple changeout anyone can do?

thanks for any info provided

[Blacky]

It's a simple change out but very tight to get to depending on which one it is, there's 2. It's much easier with the intake manifold off.
Symptoms are usually hard to feel. A little less power, especially off the line and lower gas mileage are a couple.

[trophy956]

hi since knock sensor through codes when windings are open ,no real perfomance issues,, r/s just remove the altenator ,the left side with a long ext and a swivel socket
charlie

[Cam]

Make sure you inspect both knock sensors. They are about 4-6 inches off the center line of the block on either side (between the block and the intake manifold/collector).

When I pulled my engine, a quick look determined they both need replacing. Both of them were cracked down the side exposing the inner sleeve. I am not getting any codes for them, but while my manifold is off I am replacing them both so I don't have to do it later.

You can get them at schucks (i recommend subaru) for about 35 bucks a piece. I am told they are OEM, but if someone at schucks says it, I generally take it with a grain of salt.

If you remove your Intake Manifold to change/inspect them, I would replace your vacuum lines. Unless this has been done recently, of course.

Good Luck

[blackbeautysvx]

thanks everyone for your feedback. i'll take a crack at replacing it myself. it doesn't seem like its a critical item to address so i'll post updates in a few weeks. she has 149K miles so some things are going to start failing.

[TomsSVX]

When the sensor goes bad it slacks ignition timing and increases fuel consumption as a safe guard. Replacement will mean the engine will make more power and be more efficient than letting it be.

Tom

[alia176]

Just for S&G, I tried to pull out both knock sensors out of a junk yard SVX to see how complicated it'd be. If I recall correctly, the front one wasn't too bad. The PS stuff had to be moved out of the way and maybe even the alternator The rear one was a royal PITA

At home, I already had the intake manifold out for doing all emmision and coolant hoses so it was a piece of cake. This project could be piggy backed onto a larger project if it isn't all that urgent.

My .02 cents!

[NeedForSpeed]

While I had the alternator out, my Kragen reman taking a dump after 5k/1yr, I took a look at the knock sensors. The passenger sensor is easy enough to unbolt, but the connector is tough, I squeezed the clip, but couldn't pull it apart.

I had a look at the driver knock sensor, seems easy enough to unbolt with manifold on as well, but I don't see how that sensor can be unplugged, I don't even see the plug from the back side of the manifold.

Any more tips on swapping these sensors with the manifold on?

[lhopp77]

Originally Posted by NeedForSpeed

While I had the alternator out, my Kragen reman taking a dump after 5k/1yr, I took a look at the knock sensors. The passenger sensor is easy enough to unbolt, but the connector is tough, I squeezed the clip, but couldn't pull it apart.

I had a look at the driver knock sensor, seems easy enough to unbolt with manifold on as well, but I don't see how that sensor can be unplugged, I don't even see the plug from the back side of the manifold.

Any more tips on swapping these sensors with the manifold on?

The sensors are not too expensive on Ebay. A little over $60 each as I recall.

The advice above to pull the alternator is good as it lets you get your hand into the driver side sensor. (no need to remove the manifold) The electrical connection for that sensor is accessed at the back of the engine. You can clearly see it off the back of the engine--just a little snug to get big hands around hoses to unfasten.

One of the more difficult things is to feed the wire from the driver side sensor UNDER the water tube and out the back of the manifold.

My daughter changed both by herself with me providing instructions on the phone and she is a 100lb very feminine female. Actually her small hands made it an easier job than I had.

Forgot one other thing--remove the black cover on the top of the manifold. This lets you SEE the bolt on the driver side sensor from the top and also allows you to actually access it with an extension and "wobbly".

Lee

[gbianchi]

Hello there all just wanted to share my knock sensor replacement story with y'all, all went well thanks to info found here, no I did not remove the intake just the alt and ac comp, I have small hands. To get the left side unplugged I felt like a surgeon, I used a peice of hanger as a holding tool for the wire harness, another piece of hanger to hold the connector and hemostat to unplug, shot the plug with WD40. WOW patience tester alert. After that all went well, I would say to anyone that does this to ty a peice of wire/string to the OLD ksensor so you can drag it out and ty up the new one and drag it back in there. Once you get going all this will acualy make more sence

[juice]

my light is on and the code i got was knock sensor #2 does anyone know which one is #2?

[SURTEESS]

Are both knock sensors the same p/n .......

[NeedForSpeed]

Originally Posted by SURTEESS

Are both knock sensors the same p/n .......

Yes

[dennyo]

Originally Posted by juice

my light is on and the code i got was knock sensor #2 does anyone know which one is #2?

fsm says left side