[cmitchell17]

Originally Posted by 6spdhyperblue

I’m gonna try to weld a little dot up against the ceramic part this weekend as a last ditch effort. I think it’ll work, Stay tuned

Did the welding work?

[6spdhyperblue]

My mig is curved can’t get it in there

[18ss376]

If removing the NPP valves with an aftermarket axle back exhaust without NPP will you get a CEL?

[18ss376]

Anyone?

[grampa_ss]

No, you will NOT get a CEL. I just installed MBRP axle backs a week ago. I just taped up the NPP plugs so no dirt could get in and left them hanging.

[18ss376]

Originally Posted by grampa_ss

No, you will NOT get a CEL. I just installed MBRP axle backs a week ago. I just taped up the NPP plugs so no dirt could get in and left them hanging.

Thank you, mine are about to rattle my brains out. I bought a Kooks axle back to replace the stock NPP muffler.

[18ss376]

Originally Posted by MAGAUSA

The only resolution to the npp rattle is to cut the units out. It is a total defect with these cars - which, key up the lawyers, is a part of the emissions system. I had the "fix" done by the dealer of them squirting epoxy into places where mechanical harmony couldn't be achieved by the engineers. WHAT A F-ING JOKE. Put some caulk into it dude and it will be all good. F-ing idiots. So just either live with the annoying dysfunction or cut out the cancer and go after market. That is what GM is telling us to do.

Exactly!
Why reinvent the wheel, just keep the exhaust system like the older cars.
No AFM or NPP vavles. I hate this crap.

[cmitchell17]

I think I heard someone say maybe on this forum, that putting into stealth mode and locking the valves closed causes more wear on the pin and makes it more susceptiable to the rattle. I believe mine were fixed for a while after the dealer did the TSB at about 30k or 40k. I used HP tuners to turn the startup rumble off so it wouldn't be so loud on startup, so I guess that could be why the epoxy fix didn't work for me, but I can easily see a lazy dealer just putting some epoxy on without thoroughly cleaning and it not working.

I can't really figure how having the valves closed on startup could wear it out faster, but I agree theres got to be a better fix without having to by an insanely overpriced exhaust system replacement. For example Flowmaster has just the replacement pipes and with their own valves, but I would almost rather live with the rattle than waste $700.

[s346k]

i pulled the fuse. no rattle...?

[cmitchell17]

Originally Posted by s346k

i pulled the fuse. no rattle...?

Make sure you pull the back seat down so you can hear it.

[s346k]

what back seat

[JCunningham]

the Flowmaster American thunder mufflers rattle too. my factory NPP muffler started to rattle after 6000 miles so i replaced it with the flowmasters. sounds great but the fm started to rattle after 3000 miles. it only rattles when closed or i can only hear the rattle when they are closed. Iv been thinking about putting a bushing or a sealed bearing on the butterfly shaft.

[MAGAUSA]

Originally Posted by 18ss376

Exactly!
Why reinvent the wheel, just keep the exhaust system like the older cars.
No AFM or NPP vavles. I hate this crap.

Plenty of auto manufacturers are able to source/engineer valved exhausts that work. GM, apparently not.

[MAGAUSA]

Originally Posted by cmitchell17

Make sure you pull the back seat down so you can hear it.

There's no rattle then because they are open.