MaverickFL

I installed a new power wire through the grommet located behind the ECM on the passenger side firewall (LT1). In doing so, I tore the grommet a bit too much which left a bit of an opening around the wire for unwanted noise and smells to enter.

In looking for something to seal it I stumbled upon a nice solution: Weatherstrip Adhesive. I used the Permatex brand but I would imagine other brands would perform similarly. I put it on with a finger, wiping it around the wires to make sure I got a good seal. If you let it firm up for a few seconds before you apply it, it goes on kinda snotty and grabs onto everything. You can see in the picture this stuff worked perfectly. Even though I put 4 or 5 separate blobs on my finger and wiped them around separately, as it dried they all "healed" together perfectly as you can see in the picture, and made a perfect seal. If you apply enough, It dries fairly thick and firm but remains semi-flexible and doesn't rip as I shifted the wires. I've seen some foam type filler products but I really don't think they seal and flex as well as this.
I'm not sure yet about it's resilience to heat, it might get a little soft under enough heat, but in that area I wouldn't think it would get too hot. We'll have to see how it holds up. Sometimes it's hard to find the perfect size grommet, especially if you're passing multiple lines through, so this might work well in those instances.

dailydriver

Good idea, and I got the impression THAT is what they used at the factory as a seal there (or some similar foam sealant like material) in the first place.

Yours was definitely a rubber grommet??

xenergyx

iTrader: (3)

I used flowable silicone it flows around whatever wires youve placed in my case double 8 gauge wires and itll get in the small tiny places and drys fairly well

MaverickFL

You know, probably not, at least not the same rubber that the normal hard black rubber grommets are made of. It's pretty thick around the outside but still softer than a traditional grommet. No idea what it's made of but definitely not a foam.
It has a thinner stretchy "skin" where the wire passed through, that had like a pliable latex feel to it. Overall, its kinda like a condom when it's rolled up, but would not recommend it for that purpose as it ripped pretty easily.

It was my fault, I should have cut the hole more carefully using a scissor or something, I made a slit and tried to stretch it open and it split.

I like the flowable silicone idea, would probably work as well or better but I was just trying what I had on hand. Silicone might hold up a little better to heat, I dunno.