P0332 Knock Sensor 2002 Sierra..help !

alwcurlz · April 22, 2009

New knock sensor.

New knock sensor wire harness.

Knock sensors in, wire harness setup.

Here is what we used to seal things up.

I wasn't satisfied with the instructions provided in the TSB by GM so I did what made sense. I put a bead

of sealant around the recessed area so it would seal where it should and the extra would squish up. See

next images. I should also note that these rubber grommets were coated with some kind of silicone libricant

so I used a purple cleaner and wiped them off clean before putting sealant on, otherwise it likely won't stick.

This looked great! Sealed up nicely!

alwcurlz · April 22, 2009

Next one went in nicely as well.

I then put sealant around that wire as the seal wasn't that tight on this one grommet either!! Not sure

what these guys are thinking.

Letting the sealant cure some with a wrench holding it in it's installed position. The path you see is what

path we chose as well.

alwcurlz · April 22, 2009

Ive got a 2000 sierra 2500 6.0l i do have the knock sensor codes, but it runs very smooth except a slight shake at idle. it gets crappy mileage and seems kinda slow, but i dont have a ses light?

I would like to know what the code means. Like could it mean something else is making your engine knock, or is it always a bad sensor?

I personally have powerwashed my engine twice, since ive owned it and its seen some mud soooo.

also do u always have to replace them or just clean then up?

Hey there, I replied above with my experience. I don't think you'll be able to clean them. It is likely you'll need to replace the sensors and wire harness. It is a fairly inexpensive repair if you can do it yourself. Just remember to buy the wire harness and intake seals. Good luck!

2500sierra · April 22, 2009

wow, those look bad, i bet mines terrible too i bought my truck from a country town, and im pretty sure hillbillies raped it with mudding. But i cant say im not guilty of that a time or two

thanks! so much for the pictures, lol who needs a manual.

so how did you clean up the holes, i assume the knock sensor isnt aginst oil (like not a open hole into the valley right?)

I also noticed u did a bead all around, the TSB was pretty stern about not doing that, in my opinion im 100% with you, seal em up! I bet that was just so another mechanic would have a starting point to removing them again.

ill defiantly be doing this soon, ive got a broken leg at the moment but within the next month or so ill do it, along with the O2 sensors, water pump, and rear main seal

the only thing im still curious about is, is that code just to say the sensor is bad, or can you really have a serious knock that just triggers it? but my engine runs very smooth except a bit rough at idle.

also did he notice and performance or mileage improvements.

Thanks again!

alwcurlz · April 22, 2009

wow, those look bad, i bet mines terrible too i bought my truck from a country town, and im pretty sure hillbillies raped it with mudding. But i cant say im not guilty of that a time or two

thanks! so much for the pictures, lol who needs a manual.

so how did you clean up the holes, i assume the knock sensor isnt aginst oil (like not a open hole into the valley right?)

I also noticed u did a bead all around, the TSB was pretty stern about not doing that, in my opinion im 100% with you, seal em up! I bet that was just so another mechanic would have a starting point to removing them again.

ill defiantly be doing this soon, ive got a broken leg at the moment but within the next month or so ill do it, along with the O2 sensors, water pump, and rear main seal

the only thing im still curious about is, is that code just to say the sensor is bad, or can you really have a serious knock that just triggers it? but my engine runs very smooth except a bit rough at idle.

also did he notice and performance or mileage improvements.

Thanks again!

Yeah, those sensors were covered badly with rust on the outside. I should have cut them open to see if the inside was affected but, I think it was only the connector which couldn't be repaired and expected to be reliable. You don't want to have to pull all that intake and all the other junk again to replace/fix it. The knock sensors on GM engines don't enter any oil/water jackets so no worries there. Just cleaned/scraped off the excess junk in the hole and vacuumed it out. I don't want to go in there again so I sealed it up good. The knock sensors are from what I've read, A/C volt producing devices that send a signal to the computer. They will pick up the knocks but, I'm not sure how pronounced they need to be before there's a signal sent. I'm guessing they send a signal all the time from the slightest vibration since the computer detects a faulty sensor while there is no apparent knocking sound. When you have a faulting knock sensor, it's like the oxygen sensor; the computer uses the last good input settings and stays at that setting. That will affect your fuel mileage for sure. My brother noticed a big difference in rough running to smooth, and better mileage.

Sidenote: I'm planning to replace these sensors and wire harness/gaskets, etc on my truck. I'm hoping that may take care of this valve clatter I'm experiencing. I had the rear main seal replaced when I had the transfer case taken out for suspected noise/seal replacement. I must warn you that replacing the rear main seal itself is going to be quite expensive! Also, make sure to replace the seals on your front diff. The input shaft seal and pass side output tube seal go bad on all these trucks. Make sure to at least check the fluid level on the front diff. Mine was never looked after and the bearings went bad. Run me over $700 just to replace bearings/seals on the front diff. Cost me $1,000 to have the transfer case dropped, input/output seals replaced and rear main seal replaced. The rear main seal if done by itself was at a cost of over $600. Can buy a lot of oil for that much!

Hope this info helps and hope your leg heals up good!

2500sierra · April 22, 2009

ya i really wish it didnt have a rear main seal leak. The screwed up thing was when i bought the truck the bellhousing was spotless, and i saw the truck on 2 sepetate occasions so it wasnt like he just cleaned it. then within a week a nice puddle sat underneath my truck.

but im definatly not going to try that one on my own, 600$ is worth it to me so i can take it back and bitch when it leaks again after a month lol.

Thanks again once i get around to changing the knock sensors ill post my results here.

Draenor · April 22, 2009

You should of placed some tape of stuffed some rags in the intake runners. You be amazed on what likes to fall in those.

alwcurlz · April 23, 2009

As for the sealing method I used, there is no explanation why it should not be sealed up. Unless they answer my question "why?", I don't consider it serious. I just think it's some butt covering they came up with for some reason.

alwcurlz · April 23, 2009

You should of placed some tape of stuffed some rags in the intake runners. You be amazed on what likes to fall in those.

How do you know I didn't do that afterwords? My brother used a vacuum cleaner to pull any debris from around the area and inside the ports.

2500sierra · April 23, 2009

well i bought a couple on ebay for under 50$ they are true GM sensors. Ill get the wiring harnes and im sure i need intake gaskets and maybe a TB gasket.

did you use anything on the threads of the sensors like anti-sieze or locktite just wondering?

alwcurlz · April 23, 2009

well i bought a couple on ebay for under 50$ they are true GM sensors. Ill get the wiring harnes and im sure i need intake gaskets and maybe a TB gasket.

did you use anything on the threads of the sensors like anti-sieze or locktite just wondering?

Didn't use anything on the threads. My brother did most of the work since it was his truck. Anti-seize wouldn't be a bad idea though.

2500sierra · April 23, 2009

ya ill probably put them in dry, in case the thread sealer messes with its knock sensing capabilities.

MarkD · April 23, 2009

I did the same thing on mine about a month ago. I tried to reuse the intake gasket, but ended up having to replace it due to a new leak. The gasket was around $40, but I would replace it just to keep from having to remove the intake again.

This is just speculation, but I think the reason for the gap in the silicone dam is to keep water from being retained on top of the plug. It seems as though they are not trying to seal the plug, but keep water away from it.

2500sierra · April 24, 2009

ya i figured something like that too. I really really doubt any water will get into em with awlcurlz method. We have to remember the people that put out that TSB are the same ones that installed those shitty plugs in the first place.