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First, I have stood on the shoulders of others in regards to this mod, primarily joefrontier2, and XE KING. Here is a detailed "how to" for those of you who are interested in the knock sensor relocation mod for supercharged Nissan vehicles, which I have successfully completed on my own 2001 S/C Frontier 4 X 4.
I couldn't figure out how to embed pictures in this post so here is a link to photobucket where I posted all my pics for this project:
Pictures by GothamEMS - Photobucket

The parts list:
The wiring harness, availability through Courtesy Nissan: $19.48
HARNESS AS :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com

A 1999 Nissan Maxima Knock Sensor: $134.79
RockAuto Parts Catalog
Go to Nissan-1999-Maxima-Emissions-Knock Sensor

SS M8-1.25 50mm Bolt
SS 8 Flat Washer

Before you start, disconnect your battery, it will reset the ECM, I had mine disconnected for approximately 4 hours.

I relocated the knock sensor to the rear most bolt on the S/C, closest to the firewall, see pics. I removed the OEM bolt. I chose a SS bolt for a replacement because I could not located a hardened replacement bolt, SS is harder than what I had available. I know what you guys are thinking, SS is not a good ground, but I took 120 grit sand paper and sanded the bottom of the new knock sensor as well as the surface of the S/C it was to make contact with. A little alcohol wipe, and it made a perfect ground through the sensor, which is exactly what you want. I used a M8-1.25 50mm Bolt, which is different from the N/A KS relocation bolt, and a SS #8 flat washer.

My route included working my way to the rear of the engine, locating the knock sensor and wire from the EMC, on the passenger side, between the engine block and the lower intake manifold. This is not an easy task at all, it is way down there, I could feel the connection between the wire and knock sensor but for the life of me, and an hour + later, I could not get my fingers positioned to disconnect it, sooooo, I ripped the wire right out from the sensor. The end of this wire, which is from the ECM to the KS, is a coaxial type wire, a single white core wire surrounded by another bare silver wire wrapped around this core. You will need to strip the white core wire, segregate the bare wire, and prepare them independently for soldering.

Next, get the harness you ordered and cut off the female end which does NOT fit on the new knock sensor, the end with two wires is the correct one. The end that fits on the knock sensor has ONE wire, DO NOT CUT THIS END. After removing the appropriate female end, you should have two wires, one white, and one CLEAR, the clear wire should be copper in color, strip them both.

Next, on the ECM side of the connection, you should have one white wire and one bare wire (silver in color), this is the coaxial style wire mentioned above. On the knock sensor side of the connection (the new harness with the proper female end removed), you should have one white wire, and one clear wire (copper in color). Connect the white wire on the ECM side to the clear (copper colored) wire on the KS side. Connect the bare (silver) wire on the ECM side to the white wire on the KS side. White to white is not right! Please see pics on this explanation

I made all of the electrical connections with solder and heat shrink. I used electrical tape to wrap the new harness, which mirrors all OEM electrical connections located under the hood.

I waited approximately 4 hours before reconnecting my battery. She started up without any problems, ran great, so I drove to my local Autozone to have them read the ECM.....NO KNOCK SENSOR CODE. Previously, before this mod, it always read a knock sensor code, without throwing a service engine light.

The superchargerd knock sensor relocation mod is very similar to the normally aspirated knock sensor relocation mod with the exception of the intake manifold bolt size.

This is a modification I performed on my own vehicle, which I'm eagerly looking forward to seeing if my fuel mileage increases. If anyone has any questions regarding my post or needs help with their own relocation, PLEASE do not hesitate to ask!

Thank you for reading,
Jerry Pictures by GothamEMS - Photobucket
:wav:
 

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NICELY DONE!

Everything looks right man. Hopefully now the SC runs better.

I too spent at least an hour trying to get the harness off the old knock sensor and all I could reach was with my middle finger barely on the harness.

I am curious to know if someone without the 4x4 Frontier could reach from underneath the truck and get to the sensor harness to disconnect it. With the 4x4 Frontier there are too many parts in the way to get an arm up there.
 

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Discussion Starter #3
NICELY DONE!

Everything looks right man. Hopefully now the SC runs better.

I too spent at least an hour trying to get the harness off the old knock sensor and all I could reach was with my middle finger barely on the harness.

I am curious to know if someone without the 4x4 Frontier could reach from underneath the truck and get to the sensor harness to disconnect it. With the 4x4 Frontier there are too many parts in the way to get an arm up there.
Joe, I went into it with an optimistic mind, and for the life of me, could not get the old KS unplugged. I tries for such a long time, bending my body into a pretzel, laying across my engine bay, on my back and stomach, from underneath my truck, but I couldn't do it. The best I could do was get three fingers, excluding my thumb, on my right hand, around the plug, but it was futile, I couldn't get the grip I needed. So after a very long time, at the peak of frustration, I said F*&K IT, and ripped the wire out!
Thank you for all of your help, you guys are the ones who deserve all of the credit for this mod, the rest of us pretty much followed your models.
 

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Article looks great guys! If mine goes again, I will try this. F.Y.I.--Both times I replaced mine to the stock location and my mileage increased about 2 mpg.'s.
 

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Discussion Starter #5
Just an update...I put just shy of 100 miles on the truck since the relocation mod, and just for the heck of it when I stopped by Autozone to buy new wires, I had them scan the ECM, no knock sensor code.... :thumbup:
 

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Whats the reason for using a Maxima knock sensor? I called Autozone and they have sensors for both in stock (non oem) the one for my frontier was $115 and the maxima $130. Is there any reason I couldn;t buy the frontier one from Autozone and the nissan harness and do this mod?
 

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Rockauto.com has the maxima sensor cheaper. In order to do this mod you need the maxima harness (which makes connecting the wires up easier.
 

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Will the maxima harness work with the frontier knock sensor? Rockauto.com's price is about the same as autozones and the frontier one is cheaper than the maximas.
 

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debun

you are right... Looks like rockauto dropped their Nissan OEM parts for 3rd party and the prices are higher too. That sucks!

As for your question if a frontier KS will work with a Maxima harness. If I remember right the connections are different. But, don't quote me on that.
 

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Discussion Starter #10
debun

you are right... Looks like rockauto dropped their Nissan OEM parts for 3rd party and the prices are higher too. That sucks!

As for your question if a frontier KS will work with a Maxima harness. If I remember right the connections are different. But, don't quote me on that.
The Frontier Knock Sensor will NOT work with a Maxima harness. I know this because I originally ordered a Frontier KS and the Maxima harness, and had to return the Frontier KS because it did not fit. I ended up getting the 99 Maxima KS.
 

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The Frontier Knock Sensor will NOT work with a Maxima harness. I know this because I originally ordered a Frontier KS and the Maxima harness, and had to return the Frontier KS because it did not fit. I ended up getting the 99 Maxima KS.
Cool, now I know for sure.
 

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What to do now?

Well I relocated my knock sensor and it hasn't read a code for a week until now. Today it read P0328 and also P0430 and my gas mileage is horrible. It still runs great though. I don't understand it. My truck is a 2002 S/C CC. As a matter of fact my gas mileage has sucked ever since I have had the truck. It gets around 8 to 10 mpg.
 

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Discussion Starter #13 (Edited)
Well I relocated my knock sensor and it hasn't read a code for a week until now. Today it read P0328 and also P0430 and my gas mileage is horrible. It still runs great though. I don't understand it. My truck is a 2002 S/C CC. As a matter of fact my gas mileage has sucked ever since I have had the truck. It gets around 8 to 10 mpg.
As far as I understand, the knock sensor is grounded through itself. For best results, I took 120 grit sand paper, sanded the bottom of the sensor, and the surface of the supercharger in which it makes contact with, which was filthy BTW. Clean up the mess with some alcohol, do a battery pull, and see what happens. Keep in mind that this may not be your issue, you are throwing codes, and I'm assuming a service engine light, which is not the case with a dead knock sensor. I drove my truck for a month with the knock sensor completely detached, and never threw a SES light. And how in the hell did you disconnect the connection between your stock harness and the knock sensor, that doesn't look like a Maxima harness. I think we'd all like to know, LOL!


P0328 Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
P0430 Catalyst System Efficiency Below Threshold (Bank 2)
 

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I just got done doing that, I sanded both contacts good and re-mounted the KS. And took it to auto zone and erased the codes. I also have that other code (P0430)`and I am gonna drive it hard tonight and see if I have a glowing cat under there. If not I think it is going to be an O2 sensor. Or that's what I'm told. Maybe my O2 sensor is what's causing the bad gas mileage. Thumbs crossed!

Thumbs crossed? Sorry I meant fingers, lol Also I want to sea foam this but I'm not sure if it is a good idea on the supercharger models. I haven't seen any ok's on it. Only on non S/C trucks. Any input would be appreciated. Also if so would the brake booster line be the way to go. Thanks!
 

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Discussion Starter #15
I just got done doing that, I sanded both contacts good and re-mounted the KS. And took it to auto zone and erased the codes. I also have that other code (P0430)`and I am gonna drive it hard tonight and see if I have a glowing cat under there. If not I think it is going to be an O2 sensor. Or that's what I'm told. Maybe my O2 sensor is what's causing the bad gas mileage. Thumbs crossed!

Thumbs crossed? Sorry I meant fingers, lol Also I want to sea foam this but I'm not sure if it is a good idea on the supercharger models. I haven't seen any ok's on it. Only on non S/C trucks. Any input would be appreciated. Also if so would the brake booster line be the way to go. Thanks!
Are you using premium fuel? A ping or knock from poor fuel quality may mean you knock sensor is working fine, it's may be a timing issue, in which a properly working KS is attempting to compensate for.
Also, a poor O2 sensor will instantly destroy your gas mileage, it did mine! O2 sensors are pretty easy to replace, I've done two on my truck. If I were you, and we have the same truck, I to have developed a love hate relationship with this truck, I wouldn't sea foam it.
I've had one problem after the next, with this truck, head gasket gone at 56K miles, 6 weeks out of warranty, 4 superchargers, one of which was covered, my truck is a 2001, it currently has 65K miles on it WTF!!!!!!!!!!!!!!!!!!!!!!
 

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I took my truck to a nissan mechanic and he relocated my knock sensor. It appears that he cut the coax looking wire and relocated the knock sensor and stripped that wire back and plugged that wire in the new sensor. Should I put this back and do it like everyone is doing on here. Also would this be causing my mileage problems? And will it run any better than it is now? Thanks!
 

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Discussion Starter #17
I took my truck to a nissan mechanic and he relocated my knock sensor. It appears that he cut the coax looking wire and relocated the knock sensor and stripped that wire back and plugged that wire in the new sensor. Should I put this back and do it like everyone is doing on here. Also would this be causing my mileage problems? And will it run any better than it is now? Thanks!
No, either connection will work, if wired up properly. I thought you managed to unplug your original connection, I was like HOLY $HIT, how was this accomplished? I tried EVERY SINGLE WAY TO DO IT, A FAILED MISERABLY, LOL!
From what I understand, a properly working knock sensor should do nothing but improve gas mileage, especially on a S/C 3.3L, BUT a bad O2 sensor will cripple your MPG. When I did my KS relocation, I did not put it on the side of the S/C, I mounted it to the rear of the S/C, where I felt there was more "meat" / surface area, to mock the stock location more effectively, and this location was further away from anything, which may be less likely to pick up noise from the twin screws, but...this should not be the case in ether location, the location shouldn't be a factor, I just think the rear was a good location for my truck :)
 

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Well thanks alot. How do I know which O2 sensor it is that is out. I have 4. (P0430) Is that one in particular? I'll try this and leave the KS alone for a while and see if the fuel mileage gets any better. My truck was a 1 owner and has 116,000 miles on it and the prev. owner never had any major problems. He replaced timing belt, water pump, plugs, wires, etc. at 106,000. Then I buy it and it starts to fall apart. WTF? When I bought it the ABS light was on and I thought that wasn't bad it was better than the engine light. Now look!
 

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Well thanks alot. How do I know which O2 sensor it is that is out. I have 4. (P0430) Is that one in particular? I'll try this and leave the KS alone for a while and see if the fuel mileage gets any better. My truck was a 1 owner and has 116,000 miles on it and the prev. owner never had any major problems. He replaced timing belt, water pump, plugs, wires, etc. at 106,000. Then I buy it and it starts to fall apart. WTF? When I bought it the ABS light was on and I thought that wasn't bad it was better than the engine light. Now look!
I'm not sure what code corresponds to which bank(location). I've replaced the passenger side pre-CAT O2 sensor twice, I don't recall which bank(location) came up on the ECM scanner, a decent tech, even at Autozone, should be able to provide a accurate diagnosis, that is where I had my truck scanned when the O2 sensor went bad. Let us know how you make out!
 

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GothamEMS, It appears that the only thing that hasn't been done is my coax type wire (Thin wire outside of white coated wire) being twisted with another wire and rad to the KS. All I have connected is the inside wire. Is there anything that I can do with this KS to run the twisted wire into it or will I need to purchase a new KS and re-do it all.
 
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