Knock sensor - where is it?

[mishmosh2000]

Well, because my new KS will take a couple of weeks to arrive, I decide to play with the dead old one. On my multimeter, the resistance at the terminals of the sensor itself is infinity (no continuity). Fine, it's dead. Code 0304 told me that (no CEL). Even clearing the ECU would not make the 0304 disappear.

Noticed that the metal bottom of the KS was tarnished/rusted. Also noted a crack to the plastic casing near the terminals with some metal visible. Decide to sand dremel the bottom and put some Automotive Goop sealer to the crack. Well today when I go to measure the resistance, I get a number! It varies continuously from about 14-16 M Ohms. On my multimeter, the KS has polarity. Measuring in one direction, I get no continuity and switching the leads, I get the 14-15 numbers... Putting the KS back in and resetting the ECU, I get NO CODE. I drive around, and maybe it's all psychological, but I feel like the pedal is more sensitive, ie. more power. I know the bottom rust has nothing to do with it but could sealing that crack in the casing do something? It doesn't make sense but my KS is now working (seemingly) and doesn't put up a 0304.

I'm still going to swap in my new KS when I get it but I may just apply Automotive Goop to the top casing to strengthen it...

[PhatBastard]

The CEL came back on today with a 7-7. So, replacing the KS didn't clear up the O2 sensor problem like I had hoped.

I've ordered a new O2 sensor ($82 @ thepartsbin.com).

Also, no noticeable performance gains from replacing the KS.

[shiraza]

Originally Posted by PhatBastard

The CEL came back on today with a 7-7. So, replacing the KS didn't clear up the O2 sensor problem like I had hoped.

I've ordered a new O2 sensor ($82 @ thepartsbin.com).

Also, no noticeable performance gains from replacing the KS.

phatbasard: could you make a page on your site for how to change the rear O2 sensor? i have the same problem. I took it to autozone and they said ks and rear O2 are messed up. they also told me to get trouble shoot before replacing parts, what's that? let me know if ur O2 makes CEL go away.

[THT]

CEL does not come on when the KS trips. Usually, what happens is an O2 sensor goes out and causes the KS code. Change your O2 before the knock sensor. Here's how:

Upstream O2 sensors:

Necessary tools:

*3/8" drive ratchet
*16mm O2 sensor removal ratchet (rent it from Autozone for free)
*OEM upstream O2 sensor(s)
*Anti-seize
*PB Blaster (or WD40)
*Scissors

1. Put the front end of the car on ramps or jackstands
2. Spray the O2 sensors with PB blaster (or other lubricant) to make removal easier; wait ten minutes.
3. Using the O2 sensor ratchet attachment, loosen the current O2 sensors that are installed in the "Y" portion of the Y-pipe
4. Trace the sensor harness up to the engine bay and unplug it. One will be close to the cabin, to the left of the spark plugs; the other will be clipped by the radiator, towards the front of the car
5. Cut the plastic things holding the harness; there will be multiple ones
6. Completely unscrew the O2 sensors
7. Plug in the new sensors to the now-empty connectors that the old sensors were attached to
8. Dangle the sensor from the engine bay to the underbody of the car, taking care to do it SLOWLY so you don't damage the sensor
9. Put a little anti-seize on the threads of the sensors (if there isn’t any already)
10. Screw 'em in and you're done.

Downstream O2 sensor:

Necessary tools:

*12mm wrench
*OEM downstream O2 sensor
*Anti-seize
*PB Blaster (or WD40)
*Scissors

1. Put the rear end of the car on ramps or jackstands
2. Locate the downstream O2 sensor; it is in rear-half the catalytic converter, on the driver’s side (middle of the car is where you should be looking)
3. Spray the sensor with PB Blaster or WD40
4. Trace the harness to the underbody of the car
5. Pull on the harness until the rubber seal pops free
6. Disconnect the old sensor from the harness
7. Apply anti-seize to the new O2 sensor (if it doesn’t already have some); take care not to get the compound on the sensor head
8. Screw in the sensor
9. Connect the new sensor to the harness
10. Jam the excess wiring back into the hole and close it up with the rubber seal
11. Using one of the supplied zip ties, secure any slack wiring.

~THT

[shiraza]

Originally Posted by THT

CEL does not come on when the KS trips. Usually, what happens is an O2 sensor goes out and causes the KS code. Change your O2 before the knock sensor. Here's how:

Downstream O2 sensor:

Necessary tools:

*12mm wrench
*OEM downstream O2 sensor
*Anti-seize
*PB Blaster (or WD40)
*Scissors

1. Put the rear end of the car on ramps or jackstands
2. Locate the downstream O2 sensor; it is in rear-half the catalytic converter, on the driver’s side (middle of the car is where you should be looking)
3. Spray the sensor with PB Blaster or WD40
4. Trace the harness to the underbody of the car
5. Pull on the harness until the rubber seal pops free
6. Disconnect the old sensor from the harness
7. Apply anti-seize to the new O2 sensor (if it doesn’t already have some); take care not to get the compound on the sensor head
8. Screw in the sensor
9. Connect the new sensor to the harness
10. Jam the excess wiring back into the hole and close it up with the rubber seal
11. Using one of the supplied zip ties, secure any slack wiring.

~THT

thanks for the info, appreciate it. in another subject in this forum this is what they said about changing the rear O2.

go under the car. its a 22m bolt head. there should be a plastic covering under the car, pop that off and the rear o2sensor cables should be there, and just unclip and replace with a new one.

it's from this link - http://www.automotiveforums.com/t31933.html

[THT]

Cheston knows his stuff (think he drives a TT 350Z now) but it's a little vague. And it's definitely a 12mm that you need. Good luck. It's very easy to do; before I did mine for the first time, the most I had done to my car was change the oil.

~THT

[James Dwan]

Does the 91 Maxima have (2) o2 sensors as well? I am getting the detonations sensor error & the "Org" suggested replacing the o2 first

[THT]

Wish I could tell you but most of my knowledge is 4th gen related.

~THT

[shiraza]

Originally Posted by James Dwan

Does the 91 Maxima have (2) o2 sensors as well? I am getting the detonations sensor error & the "Org" suggested replacing the o2 first

THT what percent tint is that? I'm thinking of tinting my windows. I think I want it darker than yours are. Is there a picture site that shows you how to tint the them? ...kind of like phatbastards knock sensor page.

[THT]

I don't know as I didn't put it on the car; previous owner did it. I plan to go with 20% all around soon.

~THT

[Slyprince]

Would not have found the KS without you folks. Thanks much.

My service light came on yesterday. Autozone hooked up to it and identified the KS and Bank1 O2 sensor. Can anyone confirm that replacing the O2 sensor might eliminate the KS code? I'm told that if the KS is really bad, that it could mess up the engine pretty good by firing the ignition "off sequence". So if the risk is high, I don't want to chance not replacing the KS.

Thanks for the help.

[i3o2Matt]

Originally Posted by shiraza

THT what percent tint is that? I'm thinking of tinting my windows. I think I want it darker than yours are. Is there a picture site that shows you how to tint the them? ...kind of like phatbastards knock sensor page.

judging by the picture...it looks to me as if his tint is 80%...most of the tint like that is

[shiraza]

Originally Posted by i3o2Matt

judging by the picture...it looks to me as if his tint is 80%...most of the tint like that is

Thanks for the input. I checked ohio law and it says i can have 30% in the front and any % in the back. So i'll be going with 20% in the back.

slyprince:

you can try resetting the check engine light and see if that makes it go away. I was going to do that but tomorrow i'm taking mine to my mechanic he's going to check it. his pc can tell which gave the light first (O2 or KS). I think I will reset it and see if it comes back on or not because it drives fine with no problems or loss of gas mileage.

[THT]

Yes, four out of five times your KS trips, it's because of a failing O2. Change your O2 first, reset your ECU and check for any codes.

~THT

[shiraza]

I reset my ECU and now no CEL. It's been three days now. First it was giving me the code for O2 and KS but after resetting it it's all gone. I think my engine oil was kind of low so that might have triggered it.

Now I'm planning on fixing my clock. It doesn't work. Anyone knows how I can open the panel to take the clock out? and also the knob that makes the side mirrors move.