Dreaded knock sensors

[H0E2]

Okay first I did search around and gathered a lot of information.
2002
Chevrolet Tahoe
5.3L V-8 Vin: Z (FLEX)
Mileage:194,362
4x4

Recently back in February iirc I replaced my intake manifold gaskets. I went with the expensive Fel-Pro gaskets. As I seen from research and various member suggestions I replaced both knock sensors and the harness. Everything was great until today I was cruising onto the highway and the SES came on. Plugged my scanner in (I keep it in the truck now) and got P0332 low input or no communication (something along those lines) Now three days ago a buddy and I took our Hoe's back some state game land for a little "off-road" fun. Plenty of puddles and mud some decent size water splashing as well. I'm sure what happened is water made its way into the valley center and filled those holes.( I did not RTV around the knock sensors) this brings me to my question. I read a DIY thread about creating a "Dam/Diverter" with RTV my question is that they are all specific about not completing the full circle of RTV....why???? What will happen if I seal them up? And why not while I'm at it seal the valley like on the old 350's you use RTV for valley centers. What harm will I do if I seal this up tighter then a frogs rear? As you guys know it's not exactly the easiest job changing these and parts are not cheap. I am getting a new intake manifold gasket I never re-use but just to clarify can you re-use the Fel-pro IMG? (Steel one) thank you in advance.

 

[Coatwolf]

Not sure why they emphasize not doing a full 360 on the RTV unless they want a pry point later.... but I did my knock sensors and gasket and new wire harness and COMPLETELY sealed the caps with hi temp rtv and I have had zero issues. I would just seal the crap out of them.

Im **** - I would use all new parts again if I had to redo this job...just to be sure. I used the FEL PRO gasket too but would replace it - I hate doing "RE-WORK" if that gasket doesn't re-seal you will have to do it all over again... my 2 cents

 

[OR VietVet]

First, I would never ever reuse a gasket or seal, IMO. Then I found this:

The Chevy knock sensor is located below the intake manifold of the vehicle. The intake manifold will have to be removed to access the sensor. Once the intake manifold is off, take out all the foam from below the manifold. Replace the knock sensor located on the rear and check for any corrosion or water intrusion. In case there is any corrosion in the sensor or wiring then both the sensor and harness will need to be replaced. Then apply a bead of silicon RTV around the opening of the rear knock sensor and leave a gap in the sealant at the rear of the opening. This will prevent water from getting trapped and damaging the new sensor. Reinstall the intake manifold with new gaskets to complete the procedure.

 

[H0E2]

The light has gone off but then we got some heavy rain and it came back on so I plan on replacing them soon after I get my hoe some new rubber. I am going to seal the new knock sensors completely and for the new harness I'm going to wrap that in electrical tape and the plastic wire loom hopefully never have this issue again.

 

[joshualmarley01]

We did these in a 2003 Silverado and found out the wiring harness was bad. Bought a new pigtail from a dealer and all is well.


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[Mondo]

@joshualmarley01 We did these in a 2003 Silverado and found out the wiring harness was bad. Bought a new pigtail from a dealer and all is well.

So it wasn't the sensors? Just harness? Is it possible to replace with out removing manifold.

I am also getting knock sensor code but just keep clearin. But I heard that it makes the truck run a little hesitant. And burning more fuel any truth to it. I feel it's sluggish out of stops.

 

[ezdaar]

Cannot, replace harness without removing manifold.


Yes it makes the engine run like poop.
Dead knock sensors put your timing on a flat no advance table. This makes it sluggish from a stop and consumes rediculos amounts of fuel as a safety measure to control potential spark knock.

Replace both sensors and the harness with oem parts and seal the caps.

 

[joshualmarley01]

I 2nd ezdaar


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[H0E2]

I bought everything Genuine GM parts except my manifold gasket that's the fel-pro my light went out after it dried out and has never come back on so I put it on the back burner for now. Ended up rebuilding my Rear spider gears finally went so went ahead and replaced everything bearings seals and gears etc painted the rear. One of these days I will do the knock sensors but for now it's okay.

 

[ezdaar]

]That's great, just be aware the damage is done and they are corroding.

But when you do get around to swapping them. Take the time to insulate the bottom or your intake manifold. It will greatly help,reduce heat soak and help engine from pulling timing due to heat.

Will post link to a site that sells pre cut stick on insulation when I can find it again.

The pic at this link is a forD manifold, but the list has part number for you
https://www.heatshieldproducts.com/automotive/component-specific-heat-shields/i-m-shield

Will try to find the pic of your intake, insulated asap
Here is their product. There is another I'm trying to find, that's three times thicker.
paceperformance.com/images/F132020975.jpg