Hi,
So the wifey overheated her 2001 QX4 , and after seeing it was leaking from around the bellhousing in the rear , I did a little research on that leak location and found it was either a head gasket / crossover pipe / or a hose deep inside under the lower intake manifold. Took to mechanic they said head gasket !! but fear not we can put a new JDM motor in it for $4400 !!! in a car worth $2500 I don't think so ....
had it towed home , and when I finally got the nerve to look under the hood I was pissed , they didn't even remove the lower intake ....
How can you tell if it's not the hose ?? Well we used mirrors the mechanic said ..........
I got my tools out and removed the lower intake, IT WAS THE HOSE !!!! BUT
I or the mechanic working on my 2001 QX4 broke the terminal connection that goes to knock sensor , when removing the FI harness, it's attacached to that !!
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. I have a pigtail on it's way but I need to know what wires go the which ( your photos may help) thank you in advance
HELP !!!

BUMP BUMP
So ANYBODY wired in a knock sensor ?????????

brightstar wrote: ↑

Wed Nov 07, 2018 8:45 pm

...
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. I have a pigtail on it's way but I need to know what wires go the which ( your photos may help) thank you in advance
HELP !!!

Assuming it's something most of us haven't done here, your photos of your work would greatly help us help you.

Not sure what engine you have, but the manual doesn't seem to discriminate. It says both engines should have a white wire and a shielding/ground wire that I assume will be black (or brown?? )

Hold the knock sensor upright, with you looking into the plug. The white wire goes to the right.
Hold the wiring plug upright, with you on the unwired end. The white wire goes to the left.

Some sensors are grounded differently and the spot for a wire can be plugged/capped/blanked off, but this is where your pictures would be very helpful to bring certainty.

Thank You , I've been working very late , too many projects !!!
It's a vq35 engine, 2001 QX4,
I'll strip the cover over the wires back a little more ,
and see if I can get some pics for you
in mean time I'll see if your description of how the wires are suppose to be holds true with how mine lay , (since the heat has them pretty rigid)

This is probably the perfect opportunity for you to relocate the KS so that getting to it will never be a problem again. I don't have the link but there are several youtube videos that provide all the details.

Here are some photos of what I have

http://i265.photobucket.com/albums/ii22 ... G_9105.jpg
http://i265.photobucket.com/albums/ii22 ... G_9104.jpg
http://i265.photobucket.com/albums/ii22 ... G_9103.jpg

Here are some photos of what I have
[/img]

The top photo is the wires , the lower photo shows how they come from the FI loom , under the lower intake manifold ,
My thinking is that they have been baked in that position for 16 years and that they basically should be wired into the KS the way they lay.

as you can see from the connector photo , it broke very symmetrically , impossible to tell what wire went to which side .



In this photo you can see that it LOOKS like one wire is larger than the other ........ Shielded ?

from Edbwoy :
Hold the knock sensor upright, with you looking into the plug. The white wire goes to the right.
Hold the wiring plug upright, with you on the unwired end. The white wire goes to the left.

Any thoughts you guys ?
I was thinking of wiring a pigtail on to the knock sensor , and running more wire up so that I have access to splicing it further up the loom, so that if I do wire it backwards , and get a code , I can reverse the wires so it works properly, make sense ? or does shielded side have to go on a certain terminal ?
HELP !!

I was also thinking of relocating ............
It would make the access easier , but I have read from a couple of Knock Sensor geniuses that in relocating the KS, the KS is not as effective , since the sound has to go through multiple additional gaskets , to reach the sensor .
Thoughts ??

Also Just an FYI for those ordering a knock sensor , for a 2001 pathfinder / infiniti QX4 , the Hitachi knock sensor HITACHI KNS0001 , that is suppose to fit our VQ35 engines has the wrong connector , and will not connect to ours. Yes , I ordered it and have to send it back .
It has a square connector style rather than the "rounded corner" square of our connectors and is NOT interchangeable.
So I am waiting for a new knock sensor .

A 2001 INFINITI QX4 3.5L V6
NTK ID0159 Knock / Detonation Sensor $ 105.79 $ 0.00 1 $ 105.79
Shipping First Class Mail $ 2.99
Tax $ 9.46
Order Total $ 118.24

Not cheap , but better than $290 through an Infiniti Parts site , hope it works , connector LOOKS like proper style

brightstar wrote: ↑

Sun Nov 18, 2018 10:26 am

...
My thinking is that they have been baked in that position for 16 years and that they basically should be wired into the KS the way they lay.

Sounds reasonable to me.

brightstar wrote: ↑

Sun Nov 18, 2018 11:56 am

...
as you can see from the connector photo , it broke very symmetrically , impossible to tell what wire went to which side ...
In this photo you can see that it LOOKS like one wire is larger than the other ........ Shielded ?

EdBwoy wrote:Hold the knock sensor upright, with you looking into the plug. The white wire goes to the right.
Hold the wiring plug upright, with you on the unwired end. The white wire goes to the left.

Any thoughts you guys ?
I was thinking of wiring a pigtail on to the knock sensor , and running more wire up so that I have access to splicing it further up the loom, so that if I do wire it backwards , and get a code , I can reverse the wires so it works properly, make sense ? or does shielded side have to go on a certain terminal ?

I think this would be pretty reasonable of a move as well given the circumstances. From the manual, the shielded wire came from the ground and is the non-white one.
I wish I could help further. I usually would go out to the car and take a picture of the setup as it actually sits; unfortunately I don't have an R50 anymore.

As for relocating the knock sensor, I am not in favor of that. As bothersome as this has been, hopefully you don't need to deal with the sensor itself again.

Thank You for your thought's ,
Do You think running some extra wire from the plug pigtail , up to an area at the rear of the engine, that I have access to is a good idea ?
Just in case I cross the wires and get a code

brightstar wrote: ↑

Sun Nov 18, 2018 8:52 pm

Thank You for your thought's ,
Do You think running some extra wire from the plug pigtail , up to an area at the rear of the engine, that I have access to is a good idea ?
Just in case I cross the wires and get a code

That's one of the reasons for relocating the KS to the upper intake. Flipping the wires is a snap.

So I have my new pigtail & Knock Sensor, getting ready to wire them in ,
Question : Does anybody know why the one wire is shielded ?
And does it matter that my pigtail does not have a shielded wire ?
thank you

OK, So I did a little research on KS wires , to answer my own question, and YES , the shielding is IMPORTANT !
It keeps the computer from picking up other electrical interference that it MAY construe as a KNOCK , thus retarding your timing .
So I will be shielding the extension I put on my shielded wire to the knock sensor .
I went to CLINTS GARAGE and looked at what he did
http://clintsgarage.blogspot.com/2010/0 ... ensor.html

More to come.............and photos

Glad you got an answer on the shielding. From what I see, the shielding is grounded before (I assume close to as well) the ECM. Then it terminates into the KS harness.
I realize that this info could make the "try one thing then flip wires" plan a little more crucial now, but you should verify the info I provided earlier by looking at the EC section of the FSM.

Here's a sample screenshot:

I seeeeeeeee, hmmmmmmm
from that electrical diagram , it's POSSIBLE that the other wire I am seeing is the ground FOR the shielding on the white wire.
Is that what I am seeing ????
I think I am going to strip some more of the loom back , and confirm that, or figure out the wire a little more .
I know that some people have said that on the earlier R50's , vq33 motors, or some earlier nissans lets say, that the KS had just one wire ,
Thank You for pointing this out to me , much appreciated
will get back when I have more answers
thanks

so I went up the loom to open it up , where the KS wire joins the FI harness. and guess what , one brown wire .

so I went back to the broken end and started peeling away the tape and loom
This is what I found , it looks like the shielding IS grounded at the KS !!!

This is from the factory original !!!

I am not going to peel the tape away ,
The only reason I see for it being there is the shielding has a wire spliced to it and that wire runs to the knock sensor for ground .

ANY COMMENTS ??? OPINIONS ??

Question to the electricians out there ..............
Since only one wire goes to ground , the other to the ECU , could I check continuity of each of the wires , and the one that is ground ( to shielding ) would have continuity ?

OK , I thought so but had to check .......
checked continuity the wire on the right in this photo is for ground

it is a little thinner than the other clear coated wire and has a teal insulator on it
The purple insulator goes to the ECU and is a clear coated wire.

And this is how it looks after soldering together and shrinkwrapping

And wrapping the wires with some aluminum tape for added shielding , then wrapping with tape , and putting back in loom , then wrapping the outside of the loom , like from the factory, reinstalled .... EASY


And if doesn't work , after all the intake manifolds and everything are back on ..... plan B would be to go into the harness and just wire a knock sensor to the top of the intake .

But I think this was the RIGHT way to do it .
I hope this helps someone, cause the people on these forums have helped me
THANK YOU ALL !!!

Man! You've been busy! And it looks pretty too.
I appreciate you sharing your progress with us and in pictures too. I wish I could have helped you get there faster, if I had my Qx4, I enjoyed such explorations.
So would you say, from your picture with the yellow and red shrink-wrap, that the harness is actually wired opposite of what I stated earlier? Substitute "white" with "signal/ECU wire".

EdBwoy wrote: ↑

Wed Nov 14, 2018 10:55 am

...
Hold the knock sensor upright, with you looking into the plug. The white wire goes to the right.
Hold the wiring plug upright, with you on the unwired end. The white wire goes to the left.
...

On the knock sensor relocation, I'd recommend you do some research on it before you make the move. Depending on what your long-term plans for the vehicle are, a knock sensor mounted on the intake is useless for detecting engine knock. I know 3.3 engine owners often relocate it when they get a knock sensor code, and relocating it "fixes the problem".
- On the upside, it probably will never trip your ECU to adjust timing because the intake manifold doesn't experience any combustion errors nor is it a reliable transmitter of knock pulses.
- On the downside, it will never trip your ECU to adjust timing which could lead to long term damage in the cylinder... if you ever have real knocking problems.
The KS is located in a very inconvenient location for replacement, but it is the absolute best location to reliably transmit info from the cylinders.
The relocation is a no for me, but I know others successfully do it. Either way you go, I'm eager to see how your project ends.

When looking at the sensor , from the connector side , and seeing the 2 blades inside the housing, the blade on the right went to ground, IE it had continuity with the base/center, that grounds to the engine.

from this angle above

So I checked the continuity of the 2 wires I had and the grayish wire on the right in this photo had continuity with ground


The other wire, on the left, seemed a little larger , and i think was clear originally, but had discolored to an orange tint (because of heat). I assume that it is the signal to ECU since it did NOT have continuity with ground .

Progress for today was slow , it's colder than a &^*^&%$& outside. Washington 40 degrees (ya, I'm a puss) .
But I got all the plugs changed , de-carboned the lower intake manifold , and then reinstalled the lower intake manifold , when torquing the lower intake bolts , it is recommended to do it in 2 or 3 steps , I went 8 , 16 and then to final 22ft/lb's .
Photos to follow

Plugs were Denso Iridium , I went 160,000 miles on them, they worked good for me

OK , so the gap is a little large , probably should have changed them out after 100,000 miles

Intake Manifold cleaned



It's important to clean the gasket area



And even though I have 331,000 and they haven't come loose I decided to put a little locktight on the Power Valve screws

I also wanted to share something I came across while installing the lower intake manifold ,
I replaced the water hose in this photo ,(the cause for all this in the beginning) and used the original pinch clamps,
DO NOT LEAVE THE REAR CLAMP IN THIS POSITION !
With the tabs up



It will interfere with the lower intake manifold ,
rotate the tabs of the clamp to the side almost to 90 degree's so as not to HOLD UP the rear of the lower intake manifold , and not allow it to seat against the gasket's properly .

And the round housing (toward top of photo) that the hose connects to is the rear thermostat , to control water between the heads and block, or as Nissan calls it "Water Control Valve" I replaced it as well , you can identify it online because it is a higher temperature thermostat (205) than the main thermostat (180) and it has a rubber gasket around the edge .