[joefrontier2]

UPDATE: 12/2012 - Due to the timing belt change I had the shop put my KS back to original location. I still recommend doing the location only for the non-SC v6 engine if you want to get rid of the KS code but do not want to spend ~600$ to get the KS changed.


As some of you know I did the KS override with a resistor. Well I just could not leave well enough alone. So I tried to pull off my KS wire harness without removing any part of the engine. Conclusion- Impossible to get the wire harness off a v6 4x4. I think you could get at it if you did not have the 4x4 parts like the propeller shaft in the way. No matter where I put my hand the closest I got was getting my finger on the wire harness. So with that attempt out of the way I went to order the following.

wire harness from Courtsey Nissan & a Nissan Knock Sensor from RockAuto.com. To get the knock sensor I got one from a 1999 Nissan Maxima for $69.00 (genuine Nissan package). You will need a bolt too so go get a M6-1.0 x 30mm and two washers. You may need some wire heat shrink and some electrical tape.

I placed the the KS on air intake in the middle on the left side. There are some open bolt holes there you can use. I used the middle which had grounding wires on. I moved the grounding wires ahead a bolt hole on another empty bolt hole.

Once I received the the wire harness I cut off the end that did not attach to the knock sensor (I left enough wire on the cut off harness to use just encase I would have a need for it later). Striped the wires and placed the KS on the harness then attached it to the air intake. I then used an ohm meter, one that can test Mega-ohms, from the white wire to engine ground. Do not test between the two wires as they will be no resistance. Reading should be between 500-600 ohms. Mine was .560 M-ohms and so the KS is good.


Then I removed the wires off the oil cover harness that hooks up with the old KS. You could actually cut the wires off from the harness (just leave some extra wire on them just in case you need to reuse them. The wire colors for mine were (gray and white or off white). I followed them down the large bundle of wires (you will need to cut off the electrical tape and open up the plastic bundle housing to follow the wires back.

The two wires turn into something like a coax cable where the gray wire is braided around a white wire in a single black jacket. Just carefully strip the wires and prep them to be soldered and heat shrank to the new KS wire harness. Braided wire goes with the grey wire on harness. The white wire goes with the see through copper wire on the harness. NOTE: I first wired up the white to the gray wire and the braided to the clear. The color are a bit miss leading as the white is a see through jacket. You can test this out by hooking up the wires and starting the truck. Then use voltmeter to test DC voltage on the white wire connection and then to truck ground. A voltage of 2.5 is good. A voltage of 4.75 is BAD. Electrical tape them together after you heat shrink them and then tape everything closed when done.

Also make sure you seal up your old holes on the wire harness if you removed the wires. You could place the ends right back in the holes.

If I get around to it I will post a pic of final look. I'm sort of picky as I do not like items looking like some silly noob put them together. Took me about hour to do.


This pic is slightly wrong. The blue marking for the ECU wire does not go to the right it goes right up the bundle of wire to the firewall.

 

[joefrontier2]

Here is an update from what I experience from having the resistor mod vs relocating the KS.

Having the knock sensor setup correctly I feel the truck idle better, and I can run at 70mphs under 3000 RPMs. Right from the get go I could tell that having a good knock sensor is better than having it jumpered out.

Cost: 69 (knock sensor) + 17 (harness) + 16 (shipping) = $100 + 1 hr of your time.

The MPGs will be the real test. So I just filled up the truck and we'll see how it goes this week. I was getting 13.6 mpg with it jumpered.

 

[Mountaineer]

keep us updated

 

[joefrontier2]

Update: Thoughts on resistor mod.

So I got to thinking and studying the resistor mod and to my conclusion I think it should only be used as temporary fix.

The reason that it works is that you have 4.75V coming off the ground lead and then you add the resistor between the ground lead and the hot wire (leading back to ECU). The voltage on the hot wire drops in the range of the required 2 to 3 volts required by a good knock sensor. The ECU see a good signal and it stops tripping an error code.

So here is what I can foresee is the ECU is now able to advance the timing however it wants because it is no longer in fail safe mode. I am not sure if the ECU has any other checks and balances if timing gets totally out of whack (maybe someone has some insight on this). However, if the ECU is always reading a good read how far can it advance your timing?

Conclusion is to pay 100$ for the knock sensor relocate it and rest assure that there is some control of the timing of the vehicle.

 

[fusionfronty99]

can you get some better pics of where you put it?

and also too, did you have to buy a new knock sensor?

last thing... how did you pay 69 for that harness? i got mine for 25 locally from my dealer

i think you got the wrong harness, heres the one i got and all the guys on nexterra run this harness... its only 17 dollars

CourtesyParts :: HARNESS AS

 

[joefrontier2]

Yep you need to buy a new KS. I bought it from RockAuto for around 69. You need to get a 99 maxima knock sensor. They are packaged with Nissan on them.

The harness is for a 99 maxima too and your link is correct too. The harness is 17$ plus shipping.

I will try and get some better pics up soon.

 

[joefrontier2]

I forgot to clear the KS code out of the ECU so mpg may not be so accurate. I think the engine has gotton gradually better as I have driven it from day to day. The startup in the cold weather has gotten better as I do no hear the engine knock as I used to as now I just hear 2 seconds of lifter rattle which is normal. I am going to wait for awhile of driving and monitor the MPG. If I can get the rated 15-16 MPG back for city I will be happy. Then I may try the timing advance and see where that gets me.

Here is another photo

 

[joefrontier2]

Just wanted to give you another update as for the 3rd straight day of cold engine starts I have little to no engine rattle at start up. The noise is now mostly coming from the lifters at startup. I am very happy to see that this mod has made a difference on the engine.

 

[XE_KING]

Ok.... looks like we may have a winner! I'm surprised to see that it changed your rpm's at speed.... It would be great to see my rpm below [email protected] 70! looks like Ill be doing this soon...

 

[whitehallmike]

Thank you, Joe!

This is a great idea. I just got finished. Took me about an hour. It's so good, it should be stickied somewhere so it's easier to find. :bow:

 

[CRDLIBERTY]

Im trying to figure out why this would be all that much better than resistor mod

Ok with the sensor in your location does it receive the right frequency. How close is it to stock location. I have the resistor mod seems to work and advance the timming.

 

[joefrontier2]

This is a great idea. I just got finished. Took me about an hour. It's so good, it should be stickied somewhere so it's easier to find. :bow:

I just stole the idea from some other guys off another board. But I think my pics are better than theirs... LOL

Ok with the sensor in your location does it receive the right frequency. How close is it to stock location. I have the resistor mod seems to work and advance the timming.

I think my timing got out of whack with the resistor as I mentioned earlier with this thread. I had awful rattle at first start up and till about the truck warmed up. This would make sense as the resistor doesn't send anything but a good signal back to the ECM all the time. So if the ECM adjusts the timing there is no way for the ECM to know engine knock. (This is all according to tech manuals and doing some thought into how the ECM works with a knock sensor. Just my interpretation though).

The stock knock sensor is below the lower air intake and sits on top the engine black. The air intake is bolted to head which are bolted to the engine block. The stock sensor is in optimum location the relocation is close to optimum. Will it pick up a frequency? Well the knock sensor senses knock and not frequencies. So if you take a metal object on rap it against the engine you can reproduce engine knock and in theory you should see the timing adjust.

My MPG have not improved but the horrible knock is gone and my engine runs smoother. I think I am going to adjust my timing up a notch by adjusting to my distributor cap.

 

[CRDLIBERTY]

thinking about trying this mod

I forgot which is ground which is voltage wire on truck harness. Then which is ground and sensor voltage wire on maxima harness. I did have a strange problem i was driving 100 miles towing my boat and started to knock for no reason. I got off gas pedal and it went away strange. These trucks run rich anyway. Im going order from courtesy nissan with the shipping costs i may order few other parts.

 

[XE_KING]

OK... so I went to Schucks and talked the guy into letting me use a code reader finally!( told him I would just buy it and return it to a different one if he wouldnt let me use one... lol) Sure as he!! Im throwing the code.... so its time to do the relocation.... Joe I will be asking you for more details shortly... they want $175 for the sensor at most auto stores, so I will be ordering mine from rockauto as well.... I need to get a harness to a 99 maxima correct?? and a sensor for my frontier... Anything else other than beer needed? I dont have a ohm meter.. do I need to buy one?

OK so I ordered the 99 maxima KS from rockauto and the wire harnes that you have linked above. So ill be doing this shortly!!

 

[joefrontier2]

don't need an ohm meter but it comes in handy. Do you have a walmart and a hardware store around?

You will need the bolt size I mentioned above. Also a couple washers too. Get a nice pair of wire strippers. You will need some (shrink wrap for electrical wires but you will also need a heat gun to shrink them. I used MAP gas blow torch but you have to be very carefull) for the electrical wires and or wire connectors (I like shrink wrap).

NOTE: THE WHITE WIRES ARE NOT PURE WHITE THEY DISCOLOR TO YELLOW OR GRAY. YOU WILL SEE WHAT I MEAN WHEN LOOKING THROUGH THE WIRE BUNDLES.

 

[XE_KING]

Waiting on parts

As some of you know I did the KS override with a resistor. Well I just could not leave well enough alone. So I tried to pull off my KS wire harness without removing any part of the engine. Conclusion- Impossible to get the wire harness off a v6 4x4. I think you could get at it if you did not have the 4x4 parts like the propeller shaft in the way. No matter where I put my hand the closest I got was getting my finger on the wire harness. So with that attempt out of the way I went to order the following.

wire harness from Courtsey Nissan & a Nissan Knock Seonsor from RockAuto.com. To get the knock sensor I got one from a 1999 Nissan Maxima for $69.00 (genuine Nissan package). You will need a bolt too so go get a M6-1.0 x 30mm and two washers. You may need some wire heat shrink and some electrical tape.

I placed the the KS on air intake in the middle on the left side. There are some open bolt holes there you can use. I used the middle which had grounding wires on. I moved the grounding wires ahead a bolt hole on another empty bolt hole.

Once I received the the wire harness I cut off the end that did not attach to the knock sensor (I left enough wire on the cut off harness to use just encase I would have a need for it later). Striped the wires and placed the KS on the harness then attached it to the air intake. I then used an ohm meter, one that can test Mega-ohms, from the white wire to engine ground. Do not test between the two wires as they will be no resistance. Reading should be between 500-600 ohms. Mine was .560 M-ohms and so the KS is good.


Then I removed the wires off the oil cover harness that hooks up with the old KS. You could actually cut the wires off from the harness (just leave some extra wire on them just in case you need to reuse them. The wire colors for mine were (gray and white or off white). I followed them down the large bundle of wires (you will need to cut off the electrical tape and open up the plastic bundle housing to follow the wires back.

The two wires turn into something like a coax cable where the gray wire is braided around a white wire in a single black jacket. Just carefully strip the wires and prep them to be soldered and heat shrank to the new KS wire harness. Braided wire goes with the grey wire on harness. The white wire goes with the see through copper wire on the harness. NOTE: I first wired up the white to the gray wire and the braided to the clear. The color are a bit miss leading as the white is a see through jacket. You can test this out by hooking up the wires and starting the truck. Then use voltmeter to test DC voltage on the white wire connection and then to truck ground. A voltage of 2.5 is good. A voltage of 4.75 is BAD. Electrical tape them together after you heat shrink them and then tape everything closed when done.

Also make sure you seal up your old holes on the wire harness if you removed the wires. You could place the ends right back in the holes.

If I get around to it I will post a pic of final look. I'm sort of picky as I do not like items looking like some silly noob put them together. Took me about hour to do.


This pic is slighty wrong. The blue marking for the ECU wire does not go to the right it goes right up the bundle of wire to the firewall.

Couldn't you just connect directly into the wires where you cut them off at the plug? instead of chasing them all the way down the harness? Also Joe, could you take a close up of the plug where you cut the wires off(where you have it marked gray and white)?? ( it looks like you used the bottom right wire and the gray one next to it... mine is yellowish and gray. What is the reasoning for chasing the wires all the way into the harness?? Im so dumb when it comes to this stuff... This is going to sound really dumb!! I got a multimeter and I have NO clue how to set it up...

 

[joefrontier2]

LOL - I had such a hard time with the wire colors too as white looked yellow. You want the lower right and the one next to it as it's a gray color.

Yes you don't have to chase them down the harness. I did it this way becuase I had the knock sensor resistor mod and the wires came unraveled a bit. So I just pulled them out so the 99 Maxima plastic housing could run into the main plastic housing.

Actually there is a better way to do this but I didn't go this route and should have. If you follow the wires all the way to the back of the engine (from the harness on the oil cover) there is a little plastic housing with (I believe only the two KS wires it. You could snip them there and connect them up to the new harness as well. Like I said I should have done it this way.

Just remember to think first cut second and you should be fine. There are only two wires to deal with. When finished go clear the codes and then pull the battery to reset the computer.


I am happy to announce that my MPG was gone from 12.5-13.5 to 14MPG. I know the number sucks but at least it went up. Should go up some more as the spring/summer gas should be right around the corner.


When using a multimeter from this vehicle work you really only need to concern yourself with resistance ohms (open or closed circuits) and DC voltage. I hope you bought a digital one the anal-log may not read high enough ohms for the KS .

To learn about what voltage is going through a circuit it's usually the positive wire and then to ground. Ground being usually metal part of truck or to a grounding wire on the truck. So when you wire up the knock sensor keep the wires exposed and set your multimeter to DC Voltage. Take the red lead and touch it to the white wire for the ks. Then take the black lead and touch it to ground. You should get a reading. Hopefully you get a reading around 2.5 - 3 volts.

 

[XE_KING]

To learn about what voltage is going through a circuit it's usually the positive wire and then to ground. Ground being usually metal part of truck or to a grounding wire on the truck. So when you wire up the knock sensor keep the wires exposed and set your multimeter to DC Voltage. Take the red lead and touch it to the white wire for the ks. Then take the black lead and touch it to ground. You should get a reading. Hopefully you get a reading around 2.5 - 3 volts.

Is this 2.5-3 volts with the truck running?

 

[joefrontier2]

yep turn on the truck and do the test. 2.5 - 3.0 volts. Anything above that or below that is bad.

 

[joefrontier2]