Knock Sensor or O2 Sensor

Whatsup...

Recently my milage has been awful, as low as 14.1. I also notice a slight loss in performance. The seemingly happened after I had my WSP y-pipe installed. I might be wrong though.

I ran an ECU check after i got it installed and it now throws a knock sensor code. I saw in an earlire thread that THT said sometimes the knock sensor code actually means an O2 sensor is messed up. I dont have an 02 sensor code though.

I dont want to go buy a knock sensor then not have the problem be solved. I dont know if i hear a pinging noise, is there a way to check?

thanks.

...is there a way to check? thanks.

O2 sensors produce nice on/off signal fluctuating between 0 to 1V, frequency depends on rpm. Measurable with dmm from ECU pins and/or O2 connector wires, connectors. ECU has also selftst for O2.

For KS you need a tester (for some reason ?? ECU cannot always detect), buy or lease or goto a shop for this specific tst. Dead KS means real bad mpg. Bypass resistor is one way to tst, gives performance boost IF KS is dead. See http://www.cardomain.com/ride/748507/9

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Thanks a lot, you are very knowledgeable.

Unfortunately, as a 21 year old, I really dont oknw much about electricity and bypassing and resistors, etc.

I was able to locate the knock sensor on my 95, but its very hard to get to.

Assuming the KS is dead...how do i bypass it?

It does not really give step by step instructions on your site.

....how do i bypass it?...


Get any resistor, 0.5Mohm is ok. Unplug KS connector. Push the resistor into connector, ECU-side. Hit tst the autobahn...

see at http://www.cardomain.com/ride/748507/9
http://memimage.cardomain.net/member_images/4/web/748000-748999/748507_157.jpg

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Get any resistor, 0.5Mohm is ok. Unplug KS connector. Push the resistor into connector, ECU-side. Hit tst the autobahn...

see at http://www.cardomain.com/ride/748507/9
http://memimage.cardomain.net/member_images/4/web/748000-748999/748507_157.jpg

.


got it...i think im just gonna get a new KS though. any estimates as to time required to install if the intake manifold has to be removed?

got it...i think im just gonna get a new KS though. any estimates as to time required to install if the intake manifold has to be removed?

Dunno as I havent done that job :)

Over 100 yrs engines have survived w/o KS. Maybe its the modern drivers who cannot comprehend and will not adj/clean engines if knocking occurs. ...or stereos?

Stealership will give you a quotation, time & spares. Thats 2x price u should pay, third of the time for first DIY.

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got it...i think im just gonna get a new KS though. any estimates as to time required to install if the intake manifold has to be removed?


It will cost several hours labor plus about $150.00 for a sensor. About $450 to $500. I found a shop that specializes in Nissans, they made a special tool and replace them in 20 minutes. I bought a sensor on ebay for $100 including shipping

It will cost several hours labor plus about $150.00 for a sensor. About $450 to $500. I found a shop that specializes in Nissans, they made a special tool and replace them in 20 minutes. I bought a sensor on ebay for $100 including shipping

yeah i can get one for 70 on ebay shiiped.

my boys dad owns a garage, hopefully i can him to do it pro bono.

i think im gonna try the bypass.

keep in mind i have a 95, walt, and i konw you have the earlier generation so the set up in terms of the knock sensor is differnet.

when you say disconnect the sensor...do you mean...

unplug the sub harness from the KS itself, then shove a resistor in where the sub harness normally connects to the KS?...

is that right? or is there another part of the connector towrads the front of the engine that is a lot easier to access that i am going to be putting the resistor in?

...where the sub harness normally connects to the KS?...
...

I guess theres only one KS connector, engine bay. As its disconnected, KS is dead weight, computer side now floats and needs input. This is a pull down resistor, which affects (pulls down & stabilizes) ECU input.

After bypass, do not lend the car "for Colorado holiday trip for friends". Theyll accidentally fill 87octane, then, (not hearing noises) will push pedal uphill. Engine: 4 minutes lifetime left...

Lots of cars I've driven have produced ping. When its heard, loosening pedal will stop this (=less load). My Opel had the mech adv broken; terrible noise uphill. Engine doesnt die immediately if ping happens, one has to drive accordinly, less load, higher rpm. Our forefathers drove 100years without KS... Ignorant ppl will definitely blow engine; that is why Nissan & others want to include a safety device.

I guess theres only one KS connector, engine bay. As its disconnected, KS is dead weight, computer side now floats and needs input. This is a pull down resistor, which affects (pulls down & stabilizes) ECU input.

After bypass, do not lend the car "for Colorado holiday trip for friends". Theyll accidentally fill 87octane, then, (not hearing noises) will push pedal uphill. Engine: 4 minutes lifetime left...

Lots of cars I've driven have produced ping. When its heard, loosening pedal will stop this (=less load). My Opel had the mech adv broken; terrible noise uphill. Engine doesnt die immediately if ping happens, one has to drive accordinly, less load, higher rpm. Our forefathers drove 100years without KS... Ignorant ppl will definitely blow engine; that is why Nissan & others want to include a safety device.


http://www.courtesyparts.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CP&Product_Code=22060-A32

there is a picture of the harness. as you can see it connects in two places...one to the KS itself, and one somewhere else. where should i be putting the resistor?

by the way...is the pic in ur avatar from 'The Black Hole'?

....avatar from 'The Black Hole'?

- When u put the KS in your pocket, all wires connected, you have only one free connector, one choice: plugin the resistor.
-Even if you put that short KS-wire in your pocket (shown in the pic), you still have left one open KS-connector under the hood - one choice: if this connecter wiring is followed, ECU will be found in the opposite end. Its like the pic on this thread, above.

put .5MΩ here↓-or- here↓
ECU________┌ _______┌ _K
ECU¯¯¯¯¯¯¯¯└ ¯¯¯¯¯¯¯└ ¯S

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Avatar: Whoa! It took one year for anybody to ask. In a way it is as u say: My carriage horses=VGE has two throats. The picture is from one throat, plus some phot-o-chop. In a way its the 'eternal sucker', source of my pwr....

- When u put the KS in your pocket, all wires connected, you have only one free connector, one choice: plugin the resistor.
-Even if you put that short KS-wire in your pocket (shown in the pic), you still have left one open KS-connector under the hood - one choice: if this connecter wiring is followed, ECU will be found in the opposite end. Its like the pic on this thread, above.

put .5MΩ here↓-or- here↓
ECU________┌ _______┌ _K
ECU¯¯¯¯¯¯¯¯└ ¯¯¯¯¯¯¯└ ¯S

-------------------------------------------------------

Avatar: Whoa! It took one year for anybody to ask. In a way it is as u say: My carriage horses=VGE has two throats. The picture is from one throat, plus some phot-o-chop. In a way its the 'eternal sucker', source of my pwr....

i wish i had pictures to show you. theres so mayn damn connectors.

i wish i had pictures to show you. theres so mayn damn connectors.

holy shitttttt. i just figured it out...checked the code...its gone! took it for a test drive...hollyyy shitttt..

below 3000 the thing is an animal again. im so happy.

i am getting an 0505 now, which i hear is common...what is it?

...below 3000 the thing is an animal again. im so happy.
i am getting an 0505 now, which i hear is common...what is it?

...sorry, I must have missed your q:
0505 No self diagnostic codes present (http://www.cardomain.com/ride/748507/21)

I had same feelin after bypass 'surgery' 2yrs ago. Now either keep the beast on hi octane diet or plan for new KS. Periodic [seafoam or smtg] cleanup will not hurt; peek on plugs will tell if thats necessary. Compare to NGK.com troublechart pics.

HUGE PROBLEM.

jsut yesterday, with the KS still bypassed, started getting a huge shudder. the car is vibrating almost violently. its not throwing any codes tho. i just got the spark plugs replaced too.

any ideas? it couldnt be the knock sensor could it?

i mean the thing is bypassed, how could it cause a prob. (and yes ive been using 93 octane the whole time.)

Smooth runnin engine has all cylinders workin in sync. If/When one or more cyl misses in this concert, balance is lost. ..."a huge shudder"

What is needed for this smooth concert: air, spark&injection-on time.
1. If missing is constant with same frequency, its highly probable that spark-or-injection misses constantly on one cylinder.
2. If its random, more likely the whole chorus has hiccup = control is amiss and/or fuel delivery is intermittent.

Point 1: Spark plug or coilpack bad. And/or injector bad.

Point 2: One critical input sensor [not KS] to control malfunctioning, or the controller (ECU) starved or gone nuts

- Check plugs, listen to changes as coilpacks are disconnected/swapped. Check ECU voltage. If no suspect there, try gas/injector cleanup, also make sure of fuel pressure

Smooth runnin engine has all cylinders workin in sync. If/When one or more cyl misses in this concert, balance is lost. ..."a huge shudder"

What is needed for this smooth concert: air, spark&injection-on time.
1. If missing is constant with same frequency, its highly probable that spark-or-injection misses constantly on one cylinder.
2. If its random, more likely the whole chorus has hiccup = control is amiss and/or fuel delivery is intermittent.

Point 1: Spark plug or coilpack bad. And/or injector bad.

Point 2: One critical input sensor [not KS] to control malfunctioning, or the controller (ECU) starved or gone nuts

- Check plugs, listen to changes as coilpacks are disconnected/swapped. Check ECU voltage. If no suspect there, try gas/injector cleanup, also make sure of fuel pressure


finally got a code. 0605 cylinder 4 misfire. checked the coilpack. fine. checked the injector, no reading whatsoever on ohmeter. the other two registered fine. i guess its a bad injector!

Good job from you & ECU error code! Disconnectin coilpack/injector plug(s) will have no effect on cyl4, contrast that to any other. Next, injector s-hoppin...