Disconnected Knock sensor

[Tubejig]

Hi all,

I just noticed on my 2000 Pathfinder that one of the two wires coming out from the Knock Sensor harness is cut. The cut wire is blue/red. The second wire is green and is connected. So it looks like i've been running without a Knock Sensor all along. I've only had the vehicle about 6 months, so not sure how the wire got cut.

My Pathy has 230,000 kms and runs very poorly. Feels like it's running on half power and I only get roughly 230 kilometres out of a full tank. It has thrown several codes. I don't have the exact codes but one indicated multiple misfires and another indicated a faulty Knock Sensor.

Would a disconnected Knock Sensor cause these symptoms? Can anybody describe to me how I would go abouts reconnecting the Knock Sensor wire? I don't see a loose wire on the vehicle side to reconnect it to.

Thanks for the help.

Dave

[atraudes]

I wouldn't rule it out as the cause until you get it fixed. Engines do all sorts of things to compensate for the signals that it gets from its sensors.

Are you sure it's the knock sensor though? Looking at EC-329, the knock sensor only has one white wire going into it. The sensor you're looking at is on top of the engine block, like so, right?

[Tubejig]

Thanks for the feedback. I can't say i'm 100% sure that this is the Knock Sensor, but from what i've seen online, it looks like it. And yes it's currently sitting right on top of the engine block. There's definitely two wires coming out from the Knock Sensor harness. I do have a JPEG picture of it, but can't seem to figure out how to upload it to this thread. Is there a way to add attachments?

[atraudes]

Not directly, but yes.
1. Go to http://www.imgur.com and upload your picture.
2. Once it's uploaded,
a. right-click it in the browser and click copy image URL/location
OR
b. view image, then copy the URL.
3. Paste that URL into the editor here, highlight the pasted URL, and click the Img button.

When you click the Preview button, you should see the image.

[Tubejig]

Perfect, thanks! Here's the image. Hopefully that helps.



Dave

[atraudes]

The wire that is connected looks like it was mickey-moused on. I'm going to hazard a guess that someone needed a new knock sensor at one point and bought one with a pigtail on it from a different year or model (Maxima or something) and just connected one of the wires. The second wire was being used on the other vehicle but they probably found that they could get away with it (or not) by using it like you see.

You can try disconnecting the harness from the sensor and see if it runs any differently. If it doesn't then you definitely have a bad sensor. If you go about replacing it, buy the proper sensor from the parts store, see if it fits, and see if it works. If you end up needing to buy a new harness as well, you can either hit up a pick-a-part yard or eBay.

It may also be worth your while to see if the hacked-in wire is making a proper connection on both ends. It may just be that their wiring job came loose or something.

[Tubejig]

Yes i was thinking the same thing...a hackjob gone bad. I'll try your suggestion to disconnect the harness and see if it runs any differently. If it doesn't, i'll probably just go ahead and replace the sensor and harness. I'll let you know how it goes. Thanks for the advice!

Dave

[atraudes]

You got it! Good luck and let us know how it goes!

[brightstar]

Hi,
I was wondering how it went with this knock sensor rewire ?
I or the mechanic working on my 2001 QX4 broke the terminal connection that goes to knock sensor ,
I removed the sensor and am trying to figure out which wire goes to which terminal for when I reinstall ,
I cut back the insulation and I see what I think are a brown wire and a less brown wire (white originally ?)
but I am unsure of which goes on which terminal of the KS , any help would be appreciated.