Good day all-

Been a while since I've posted or visited the site. I am planning on replacing the bad knock sensor on my 2003 X. Just wondering if anyone had actually attempted this on their own (not just the resistor workaround) and could provide some advice or input. Also, if anyone knows if the alternate mounting location trick will work for passing state inspection, please let me know! Thanks, and Happy Holidays!

Why replace it? Seeing as how you have a normally aspirated engine theres really no need as it does not do anything to the engine performance.

I did mime on my 2000 v-6 with very little problems. The part is a little costly, it took about four hours, make sure you have all your gaskets on hand, on my 2000 you have to replace all 6 fuel rail insulators.

That is not entirely true. When the code goes off it retards the timing. Therefore causing reduced performance/gas mileage.

Whenever I reset mine I notice a slight mpg increase.

S.

I didnt think it retarded the timing on a non sc engine. I know it did on on my supercharged frontier. The KS is a one reset sensor meaning it resets by turning the engine off and on. Reseting it by clearing the code does nothing till the engine restarts.

In my case the KS who throw a code as soon as I started the engine which meant the timing would never advance. I bypassed mine with a resistor and noticed a definite improvement in performance and mpg.
I believe that the ECU will advance the timing under the right conditions until it reaches max advance. I don't know how long it takes to get to full advance but if the ECU gets a KS code it will retard the timing.
The KS has a one trip logic meaning each time the engine is started the ECU starts from a "clean slate".
On a SC engine I believe the KS code will cause the SC to go into bypass made as well as retarding the timing.

My KS is kicking a code along with the Driver side O2 sensor (whole nother story) I dont see a change in my performance, I can still hear the SC kick in also. Now I may oblivious to the change if there is one if is has been running like crap for so long. If that is the case and I get the KS replaced, It will be like a new car, not.

IIRC dagerdoggie replaced his and it took him about 10 hours straight. It's definitely a big job.

Here's a picture for you. It's right in the valley so replacing it requires removal of the upper and lower intake manifolds.

I do remember some 3 years ago when I took the engine out that there was a plug in around where the head/block and bell housing came together on the left rear of the engine, Ill have to looke for the hook up around there. I can tell ya that there was not any hook up or wires there when I put it back togeather. Wonder what it feeds off of (how it gets its data) off the fly wheel maybe? or off of #6 piston...I dont know, but Ill figure it out.

That would be the crankshaft position sensor.

Mine did the same thing. It was throwing the knock sensor code and the driver side O2 sensor code. Mine is also a s/c, and there was no decrease in performance. We reset it, and the SES light came on again about two days later. It still ran fine. After about a week and half, the SES light went off, and it still runs fine. My philopsphy -- if runs ok leave it alone.

k_enn

All the time I have had my 2000 SE the KS code has been there and I always get 19-20mpg on the highway so I never did anything about it.

It looked like it was more work than it was worth to me!

Tom

I know this is an old thread but how does one by-pass the knock sensor with a resistor? My KS code is showing and I really don't get good gas mileage at all 14-16, 18 on a really good day. Seems easier to by-pass then to replace

I did mime on my 2000 v-6 with very little problems. The part is a little costly, it took about four hours, make sure you have all your gaskets on hand, on my 2000 you have to replace all 6 fuel rail insulators.

Was specifically looking for the way to bypass the KS like k1w1t1m did earlier on the thread. Any help would be great since I don't put premium fuel in and todays gas is all stinky.

Here is a write-up done by Daggerdoggie on his S/C X.
He didn't do the resistor mod, he replaced and relocated the KS onto the intake manifold using a custom harness be made.
Take a look at the pix on the link below.
http://www.unyxterra.com/forum/viewtopic.php?t=2071

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Ok, I could do a how to on the stock knock sensor replacement. Been there, done that. It took me about ten hours and the dealer says that it's a six hour job. So, at that rate you are coming close to 1K at the dealer, or a long day on your own.

Now that I have this worked out, it can be done in less than an hour once you have all the parts.

You will need:

Nissan Knock sensor: Part # 24079-31U01 - by the way, a lot of them are the same. I know the Subaru part looks just like it so a lot of them may be similar. If you get something else for cheap, it may be worth a try. Nissan's list price is $173.

Wiring harness: Maxima Harness Part #22060-7B000 - Note here. The one I had didn't work, so I made my own with a few pieces of wire and small connectors for less than a buck at Radio Shack. I'll get into that later.

1 2" long (50mm), 8mm, 1.25mm thread bolt - This is for the SC version. I'm not sure about the NA aspirated engine, but if I check, I bet it's about the same. The knock sensor is 3/4 thick, so wherever you mount it, the bolt has to be that much longer. It also has to be mounted solidly on the main part of the motor.

Here's the wiring harness. It's the same location on all first gens, but the wires are different colors. Mine did not match up with my ESM so I had to trace wires, but the location is the same for all.

The connector on the top of the passenger side valve cover, toward the front. There are two connectors mounted there, a gray one on the right (left in the picture) and a green one on the left of the vehicle (right facing in the picture). You want the green one on the right. There are a lot of wires in this connector.

The wire which sends voltage from the knock senor to the ECU is the off-white one, it's on the bottom right of the plug that pulls out of where it is mounted on the valve cover. I have cut and pulled back the loom material. In this picture I have turned the wiring connector so the wire is now on the top right. The shielded ground is a gray wire just below on the right (you can't really see it in the picture).

Now here's the trick. There are two terminal that come out of the knock sensor With the Maxima harness, there is only one wire coming from the connector, but two to the harness. It's a small coax cable. The two terminals are to check the resistance of the knock sensor, but only one sends voltage to the ECU. Which one, I had to figure out. This is also why I don't get why the resister mod works. The knock sensor sends voltage to the ECU, it's cold resistance is 500 - 600ohms, but it sends about 2.5 volts to the ESU at idle. It's a piezo electric generator (think speaker in reverse) and generates voltage through vibration from the engine. When the engine knocks, it increases the voltage and you get an error code P328. If it fails, you get either P328 or P327 (low voltage). Although I digress, I don't get how or why the resistor mod works, but others say it does and I don't need that argument with Brent. Perhaps one of you electrical gurus can explain why.

Find and cut those two wires on the bottom right of the harness. Give yourself about one inch from the connector so you could resolder the wire if you make a mistake.

You are connecting the new wires on the ECU side of the harness, which is the part that unplugs off the valve cover (towards the front of the truck). Strip the wires about 3/8" and cover the wires in the plug so they don't short (I used small shrink wire wrap). Solder two new wires about 8" long on the harness and cover with shrink wrap.

Here's where I relocated the knock sensor. I played with several locations and this seemed to fit the best and was clean and out of the way. Check the torque specs since you are working on an integral, sealed engine part. The SC is 20ft/lbs.

This is the harness I made. Again, you can get the $20 Maxima one, but I had no luck with it. If you do, you cut off the male end plug and solder those wires into the harness. I took the knock sensor to Radio Shack and got two small blade terminals for less than 50 cents

I used a voltage meter to figure out which terminal on the knock sensor was used. You can just experiment. There are only two. Once the wires were soldered, I slipped on the blade terminal onto the knock sensor and filled the connection with black RTV.

Here's the finished product.

I hooked up my laptop to the truck, started it up; cleared the old code and viola...code is gone!

Here you go

http://www.nissanoffroad.net/messageboard/index.php?topic=1921.0