timharber

I thought this would be the best place to ask.

I have a 2005 Hummer H2 that keeps throwing a bad knock sensor code. I'm going to replace both sensors and the harness but having not ever opened up an LS engine, what else would you replace or upgrade while the top end is apart?

Thanks

Tim

conan

iTrader: (5)

Intake manifold gaskets.

timharber

I was planning on all of that but having never worked on an LS, I didn't know what else made sense. I'm an old gear head and noty familiar with these LS engines.. Would it make sense to replace water pump, thermostat, oil pump?????? anything? I'd love to say I was putting twin turbo's on my H2 but that's not in the cards yet!

R6cowboy

iTrader: (3)

Other than intake manifold gaskets, I can't think of anything else. The intake on the LS motors are extremely easy to remove and install. No point replacing any perfectly working components unless it's very high mileage unit.

conan

iTrader: (5)

Nothing else needs to come off other than the intake. Be sure to put your hand behind the intake and feel for the big vacuum hose to the brake booster. You can get it stuck on the oil pressure sending unit and break it when you pull it forward. Just slide the intake forward slowly and move the hose out of the way when needed.

tigersooner

Should I replace the knock sensor if upgrading intakes ?

Mercier

iTrader: (15)

I would. Water collects in the holes where these are installed and corrodes them. Real design issue.

See top of pic at the following link.. I used (grey in this pic) silicone to build a little ring up around the holes so that when water/etc. gets under the intake it will hopefully mostly flow around the holes instead of in. The harness has rubber stoppers built in but they don't seem to keep the moisture out. Eventually though condensation will find its way in there and do its own damage but not as quickly as water flowing right in. You'll find a foam baffle under front and rear of the intake designed to keep junk/water out but they aren't 100% effective.

http://1drv.ms/1uzXeiR

Once I go back in there this weekend, I am thinking about drilling a couple of small holes in the rubber grommets and put a tube in there to discourage condensation collecting there. Then again, this vehicle lives in the garage now so that may be overkill.

Good luck!

tigersooner

Does autozone or other shops have replacement foam baffles? Is there higher density better foam to buy?

Mercier

iTrader: (15)

Not that I have seen but I haven't checked everywhere. I can tell you Autozone around here doesn't seem to have it. I also purchased TBSS/later style truck intake new and it did not come with the foam baffles. My Jeep doesn't see mud anymore so I just left them out the last time I had it off. Not sure if that will bite me eventually but knock sensors were swimming and completely shot so I figured it couldn't get much worse.

It's possible that the foam baffles harden and/or shrink over time and become less effective but I have never had my hands on a new set to make that call.