Knock sensor replacement issues.

[ScottyBoy]

I just did mine last week. I have heard on another forum that it is imperative to torque the knock sensors to EXACTLY 15ft/lbs , no more and no less. If torqued more than 15, it will be overly sensitive and give you a false knock sensor trouble code. I suspect that this is what your issue is. I had to actually go out and buy two torque wrenches when I changed mine. Luckily, Harbor Freight was having a Father's day sale and had them on sale for only $10 each!
I would get a 1/2inch drive torque wrench that will read 15 ft/lbs, and pull the intake back off and redo it. You should be able to reuse the intake gasket since its new, and just redo the RTV sealant around the knock sensors.

 

[pnwdan]

Most people don't realize they can use an inch/lb torque wrench as well. 12 inches in a foot X 15 ft/lbs = 180 in/lb

 

[bottomline2000]

And don't put any dialectic grease on the sensors either. Spend the money on the right tools and save yourself the grief. Me personally, I prefer to not use a torque wrench at its highest or lowest settings..getting a 1/4" wrench to fit a 22mm socket is going to be interesting needless to say but possible.

sent from my lollipop

 

[Danzigman]

Did you say you put RTV in the plugs?

Just like bottom line did in his picture.

 

[pnwdan]

Just like bottom line did in his picture.

The giant plugs not the electrical connections though right?

 

[ScottyBoy]

The giant plugs not the electrical connections though right?

That's what I did to mine. I put blue RTV silicone on the rubber grommets that cover the sensors. Plus I made a 1/2 inch U-shaped "wall" around the rear sensor to divert any water or other fluid from settling on the rear sensor. That's what every GM service bulletin says to do when replacing the knocks sensors.
I wish I had a picture of how I sealed it, bug I do have a picture of my old knock sensors. The rear sensor was corroded as all hell, and the front one still looked basically new. There was about an inch of water in the cavity with the rear sensor that I had to suck out with a shop vac. I then blew it out with air to make SURE that it was dry before installing the new one.
I guess you can look at my picture and figure out which sensor was the rear sensor.

 

[pnwdan]

That's what I did to mine. I put blue RTV silicone on the rubber grommets that cover the sensors. Plus I made a 1/2 inch U-shaped "wall" around the rear sensor to divert any water or other fluid from settling on the rear sensor. That's what every GM service bulletin says to do when replacing the knocks sensors.
I wish I had a picture of how I sealed it, bug I do have a picture of my old knock sensors. The rear sensor was corroded as all hell, and the front one still looked basically new. There was about an inch of water in the cavity with the rear sensor that I had to suck out with a shop vac. I then blew it out with air to make SURE that it was dry before installing the new one.
I guess you can look at my picture and figure out which sensor was the rear sensor. [emoji38]

View attachment 64045

That's pretty wild. I swapped my engine at 165k and mine didn't look like that. They looked clean. Nothing in there.

 

[ScottyBoy]

That's pretty wild. I swapped my engine at 165k and mine didn't look like that. They looked clean. Nothing in there.

About 2 years ago I pressure washed my engine to clean it, because I was replacing the valve cover gaskets that were leaking oil down the heads. I bet that's how the water got in there. The knock sensor code started popping up about a year ago, and I would clear it then it would go away for a few weeks then pop up again. Then around 6 months ago it pretty much came right back on no matter how many times I reset it with my code reader. So this repair has be on my "to-do list" for about six months now, But it hasn't been a top priority because I don't drive my truck as much anymore since I'm unemployed. It sits in the driveway most of the time. But we had to take a road trip this week, and I did NOT want to be crammed in the damn Altima for six hours, so I went ahead and fixed everything on the Burban that needed to be fixed. I replaced the knock sensors, air filter, cleaned the throttle body, got two new tires, and replaced a window regulator all to prepare for this road trip.

 

[Danzigman]

The intake crimped the wire on the harness when I reinstalled the intake.

 

[pnwdan]

The intake crimped the wire on the harness when I reinstalled the intake.

Damn