I was throwing codes like a bitch and my tech-o-meter was busted.

Upon ripping the intake off, I noticed the top of the rear knock sensor was wet. When I took the knock sensor cable off I noticed the entire sensor was under water. Apparently, every time I went through a car wash or drove in the rain the water went under the intake, over the valley cover and right into the kncok sensor holes. I'm sure this had been happening for a long time since the sensor was corroided from the water.

1. I removed the LS6 valley cover, replaced it with a new one. I used high-temp silicone on the black cable plugs to ensure the sesnsors remain dry.

2. I checked the resistence of the cable - OK

3. Replaced the cam sensor, and MAP sensor

4. took the sponge off the back of the LS6 intake and reassembled unit

It has been running fine for two days now with no check engine lights. Even my tech-o-meter works great...

I suppose we can add this problem to the growing list of GM defects that we Gen 3 owners love about our cars.... So far I can think of these:

1. bad oil pumps that go dead often
2. rings and pistons that slap
3. rocker arms that spill their needle bearings
4. push rods that bend like my elbow
5. lifters that collaspe
6. flooding knock sensor caves

Remember this - next time - do not buy a GM hot rod!

 

Considering the numner of factory defects in the Gen 3 series engines GM should recall these dogs...

 

Yeah, but in spite of all of that, we STILL love these things!

And the knock sensor issue is a known issue, one that GM will fix for free if you take it into them. They do just what you did....replace, dry, & silicone.

 

Yeh, they are fast as hell but watch out for GM's little surprises!

Now we all know why GM has the worst resale value of any vehicles except the Yogo....

 

Really?

 

You say that they replace knock sensors for free....is this only for warrantied cars or anybody???

 

ttt.... does anyone know??

 

Na....my new knock sensor cost $75 bucks from the rip off GM dealer.... I assume knock sensors are dealer only items....right?

 

Not at all - rockauto.com has them for $34.

 

I should NEVER buy anything from the GM dealer in my town!

 

I hope my sensors stay dry.

 

Has anyone else had the wet knock sensor problem?

Thanks,,,

 

I was planning on replacing the knock sensors when I do the intake, thanks for the lead on cheap parts.

 

BS!!!!! I KNEW IT!!!!



I took it to my local chevy dealer last time there was a knock sensor problem on my car and the service writer was fighting with me...I threw the knock sensor code, had my friend Jeff replace em and throw the LS6 manifold on there, I wasn't present for the install but he said they were COVERED in oil....I'm sure water is getting in there too....maybe I should stop cleaning my engine...

 

Hey Robert, I had the same problem a couple years ago. I did most of the stuff you mentioned: replaced both sensors and the wire, removed the foam square under the intake, made silicone dams, was careful where I routed the wire before installing the intake, and my reason for responding is to tell you that the problem was completely solved, no more codes or issues whatsoever, and it's been over two years since I fixed it. I'm glad to hear that you removed the foam square because it's notorious for "wicking" up water that gets near the back of the intake. Even though the problem is solved, I'm very careful about washing my engine, and I try to keep water away from the back of the intake.

What's cool about these cars is that once you get these issues solved, you got a kickass muscle car.

This is beside the point, but I had a lot of engine noise before my cam install, and after changing the springs, pushrods, and retorquing the header bolts, the engine sounds tight as hell. You can hear the valvetrain working like a sewing machine, but it sounds tight and healthy.

I love the heck out of my car after making up for GMs deficiencies. It's DEFINITELY worth it.

Long live the GREAT f-body!!!!

 

there is a TSB out on this problem. I had mine replaced and when they took them out, the old ones where harder then a rock.

 

WicketMike : will you please post the the TBS # as I have the problem
Thanks. Johnny
PS::please PM me in case I lose this post

 

yes I would love this TSB number also...



the dealer fought with me telling me it wasn't an issue and just to fork over the 500 dollar labor charge...I believed them and had a friend replace the sensors about 5-6 months ago....I am REALLY ticked off now because it's throwing codes again

 

i dont have the number anymore.
I found out about this on the corvetteforum.com about 1-2 years ago. i think they had a sticky or something for tsb's.

 

I have the same problem my bank 2 sensor is under water now in the middle of replacing it