NPP Rattle fix?

biker2k · 03-19-2019, 11:10 AM

Has anyone successfully fixed the npp rattle permanently with the epoxy or otherwise...

I have that rattle but I am pretty sure they wont honor my warranty with the rest of the exhaust work I've done ….

if so what EXACTY was done to fix it....

otherwise I guess ill live with it...

6spdhyperblue · 03-19-2019, 07:10 PM

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

njweatherman · 03-22-2019, 07:52 AM

Have you guys tried pulling fuse#51 to keep the valves open all the time? That may help with the rattle.

biker2k · 03-22-2019, 12:52 PM

I want to keep npp functionality

enzia35 · 03-22-2019, 05:59 PM

You can do the TSB fix yourself, making sure everything is cleaned correctly.

cmitchell17 · 03-22-2019, 06:49 PM

Keep in mind if you have an automatic you have the same valves further up in the exhaust that rattle the same way. The bad part about it is the exhaust is welded up and no way to get epoxy to it.

6spdhyperblue · 03-22-2019, 06:57 PM

The tsb failed twice here. Gonna try putting a bead there tomorrow

6spdhyperblue · 03-24-2019, 02:49 PM

They are further in than I remembered. No way getting the mig in there

I went into hptuners and tuned out the rattle so it’s either open or closed. The part open is when it’s rattling. Not worth anymore of my time.

RobbyBeefcake87 · 03-25-2019, 11:47 AM

I'm suffering a bit of npp rattle as of late. Thought it was the check valave getting stuck but it's definitely the npp rattle. I always have it on track exhaust but if I flip to touring for a few minutes then back to track it goes away. That's seemed to keep it quiet for about a month or so.

cmitchell17 · 03-25-2019, 06:22 PM

I just took my whole exhaust out and cut out the section with the AFM valves. After all that money spent and time and effort, the rattle is still there, so it wasn't the AFM valves rattling at all apparently. I have already had the epoxy fix done under warranty, I can't remember if that worked initially, I think it maybe did, but now its back and apparently its the rear valves again. At least I can get to the rear valves easy, but now ive cut up and ruined a perfectly good exhaust and when I put it together it was kind of a hack. I can't believe we have to deal with this, i'm way out of warranty now.

MAGAUSA · 03-27-2019, 10:35 PM

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.

cbr1100xx · 04-06-2019, 12:43 AM

Quote:

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.

I assume NPP rattle would also potentially affect '19s as well?
I'm looking at a base '19 SS w/no NPP. Maybe it's better that way. Can just add the GM performance exhaust for a bit more sound and be done with it.

6spdhyperblue · 04-06-2019, 06:30 AM

Quote:

Originally Posted by cbr1100xx

I assume NPP rattle would also potentially affect '19s as well?
I'm looking at a base '19 SS w/no NPP. Maybe it's better that way. Can just add the GM performance exhaust for a bit more sound and be done with it.

If you don’t need dual mode, you can always buy the quad tip valance and something like a corsa for a similar price to the npp option

cbr1100xx · 04-06-2019, 01:55 PM

Quote:

Originally Posted by 6spdhyperblue

If you don’t need dual mode, you can always buy the quad tip valance and something like a corsa for a similar price to the npp option

I like dual mode exhaust. The look and the sound. I just don't want to deal with the NPP rattle if it comes.

And I've got a decent deal on a base '19 white 1SS manual (no NPP). $32761.
I don't care that much about the valance or quad look. I'd just add the GM performance exhaust for non-npp.

03-19-2019, 11:10 AM	#1
biker2k Drives: 2018 2ss 1le Join Date: Jan 2018 Location: Huntington, NY Posts: 474	NPP Rattle fix? Has anyone successfully fixed the npp rattle permanently with the epoxy or otherwise... I have that rattle but I am pretty sure they wont honor my warranty with the rest of the exhaust work I've done …. if so what EXACTY was done to fix it.... otherwise I guess ill live with it... __________________ 2018 2ss 1le roto fab dry, Stainless works 1 7/8 lt to 3'" x pipe with highflow cats to stock npp, soler 95mm t/b, edelbrock 2300, LT4 fueling , jms bap and dsx flex fuel, 618/620 on e45 rwhp Jannetty Motorsports tuned

03-19-2019, 07:10 PM	#2
6spdhyperblue Drives: 6th gen Join Date: Aug 2013 Location: US Posts: 3,675	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 __________________ ‘22 2SS 1LE M6 Summit White - RF, Flexfuel, LT2 intake, 95mm tb, ATI udp, VT ramair, full 28” dragpack - 11.68@122 ‘16 1SS M6 LT2 intake + boltons on DR 11.0@126+ (Sold)

03-22-2019, 12:52 PM	#4
biker2k Drives: 2018 2ss 1le Join Date: Jan 2018 Location: Huntington, NY Posts: 474	I want to keep npp functionality __________________ 2018 2ss 1le roto fab dry, Stainless works 1 7/8 lt to 3'" x pipe with highflow cats to stock npp, soler 95mm t/b, edelbrock 2300, LT4 fueling , jms bap and dsx flex fuel, 618/620 on e45 rwhp Jannetty Motorsports tuned

03-22-2019, 06:57 PM	#7
6spdhyperblue Drives: 6th gen Join Date: Aug 2013 Location: US Posts: 3,675	The tsb failed twice here. Gonna try putting a bead there tomorrow __________________ ‘22 2SS 1LE M6 Summit White - RF, Flexfuel, LT2 intake, 95mm tb, ATI udp, VT ramair, full 28” dragpack - 11.68@122 ‘16 1SS M6 LT2 intake + boltons on DR 11.0@126+ (Sold)

03-24-2019, 02:49 PM	#8
6spdhyperblue Drives: 6th gen Join Date: Aug 2013 Location: US Posts: 3,675	They are further in than I remembered. No way getting the mig in there I went into hptuners and tuned out the rattle so it’s either open or closed. The part open is when it’s rattling. Not worth anymore of my time. __________________ ‘22 2SS 1LE M6 Summit White - RF, Flexfuel, LT2 intake, 95mm tb, ATI udp, VT ramair, full 28” dragpack - 11.68@122 ‘16 1SS M6 LT2 intake + boltons on DR 11.0@126+ (Sold) Last edited by 6spdhyperblue; 03-25-2019 at 05:50 AM.

03-22-2019, 07:52 AM	#3
njweatherman Drives: 2018 Camaro 2SS, redline edition Join Date: Jun 2013 Location: Hackettstown, NJ Posts: 209	Have you guys tried pulling fuse#51 to keep the valves open all the time? That may help with the rattle.

03-22-2019, 05:59 PM	#5
enzia35 Drives: '16 Garnet Red 1SS Join Date: Mar 2014 Location: College Station, TX Posts: 3,450	You can do the TSB fix yourself, making sure everything is cleaned correctly. __________________ '16 Camaro 1SS '18 Miata GT Gone: '01 Camaro, '14 Camaro, '90 Miata

03-22-2019, 06:49 PM	#6
cmitchell17 Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016 Location: US Posts: 1,201	Keep in mind if you have an automatic you have the same valves further up in the exhaust that rattle the same way. The bad part about it is the exhaust is welded up and no way to get epoxy to it.

03-25-2019, 11:47 AM	#9
RobbyBeefcake87 Drives: 2018 Camaro SS 1LE Join Date: Aug 2018 Location: Tampa Florida Posts: 1,980	Rattle I'm suffering a bit of npp rattle as of late. Thought it was the check valave getting stuck but it's definitely the npp rattle. I always have it on track exhaust but if I flip to touring for a few minutes then back to track it goes away. That's seemed to keep it quiet for about a month or so. __________________ 2000 Miata - aventi storm wheels, roll bar. 2019 Mustang GT pp1 - svt pp2 wheels, mbrp cat back, sync 3 upgrade, p1x procharger + stg2 intercooler. 2018 Colorado zr2 - zr2 sport bar, showcase spare tire. 2018 Camaro SS 1LE - GM cai, black bowties, suede knee bolsters, 1le plate frame, black fuel door, dark tails + 3rd brake light, euro side markers + led's, GM all weather floor mats, velossatech big mouth, GM strut brace. 2017 Corvette Grandsport (sold) - untouched. 2006 GTO (sold) - iat relocation, air box mod, monero side marker lights.

03-25-2019, 06:22 PM	#10
cmitchell17 Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016 Location: US Posts: 1,201	I just took my whole exhaust out and cut out the section with the AFM valves. After all that money spent and time and effort, the rattle is still there, so it wasn't the AFM valves rattling at all apparently. I have already had the epoxy fix done under warranty, I can't remember if that worked initially, I think it maybe did, but now its back and apparently its the rear valves again. At least I can get to the rear valves easy, but now ive cut up and ruined a perfectly good exhaust and when I put it together it was kind of a hack. I can't believe we have to deal with this, i'm way out of warranty now.

03-27-2019, 10:35 PM	#11
MAGAUSA Drives: 2017 Hyper Blue 1LE Join Date: Dec 2016 Location: Tampa Posts: 579	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.

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