NPP stays open... doesn't close. Why?
Thread Starter
Heel & Toe
Joined: Apr 2023
Posts: 15
Likes: 0
NPP stays open... doesn't close. Why?
Howdy
I just acquired a C-7GS LT2. It's good to be back in a Vette! The previous owner may have made some changes to the NPP. IDK. The valves stay open all the time. I went thru the engine mgt and tried all the settings. The fuse is in place. What should i try next?
thanks
I just acquired a C-7GS LT2. It's good to be back in a Vette! The previous owner may have made some changes to the NPP. IDK. The valves stay open all the time. I went thru the engine mgt and tried all the settings. The fuse is in place. What should i try next?
thanks
Safety Car
Joined: Dec 2012
Posts: 3,858
Likes: 1,863
From: St. Louis Metro East IL
The NPP fuse is in the under hood fuse box. It is labelled EXH2 on the schedule...
EXH1 fuse is the V4/V8 exhaust valve.
Fuse numbers have changed over the years, but the actual position has not.
Just to clarify...
Ron
EXH1 fuse is the V4/V8 exhaust valve.
Fuse numbers have changed over the years, but the actual position has not.
Just to clarify...
Ron
Instructor
Joined: Feb 2018
Posts: 227
Likes: 23
If u see an add a fuse attached to a small black box then someone installed an after market valve switch. Try pressing the 2nd or 3rd button on ur home link buttons on the rear view mirror to open or close the valves.
Drifting
Joined: Jun 2013
Posts: 1,428
Likes: 478
From: Maryland, USA
well if changing the exhaust management in the infotainment system doesnt change anything regardless of car mode
then i would lean towards fuse as well and/or even ensuring it wasnt bypassed at the actuators at the mufflers for some reason / somehow.
do the mufflers look factory?
then i would lean towards fuse as well and/or even ensuring it wasnt bypassed at the actuators at the mufflers for some reason / somehow.
do the mufflers look factory?
Last edited by mdformula350; Apr 13, 2023 at 05:36 AM.
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
All good ideas in here.
Check the fuse
Engine bay fuse box:
For the 2014, it is fuse 41.
For the 2015 - 2018 it is fuse 42.
For the 2019 - it is fuse 87
If the fuse is there AND it tests good, next idea
Is there an "Add a circuit" in the fuse slot?
Get rid of it and plug the correct fuse in the slot
Still have a problem?
Check to see if the wiring to the muffler and NPP valves is connected
Please show us a nice close-up of the exhaust tips (A picture is REALLY worth a 1,000 words)
Then come back and let the gurus resume their crystal ball gazing for you.
Elmer
Check the fuse
Engine bay fuse box:
For the 2014, it is fuse 41.
For the 2015 - 2018 it is fuse 42.
For the 2019 - it is fuse 87
If the fuse is there AND it tests good, next idea
Is there an "Add a circuit" in the fuse slot?
Get rid of it and plug the correct fuse in the slot
Still have a problem?
Check to see if the wiring to the muffler and NPP valves is connected
Please show us a nice close-up of the exhaust tips (A picture is REALLY worth a 1,000 words)
Then come back and let the gurus resume their crystal ball gazing for you.
Elmer
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Supporting Vendor
Joined: Aug 2007
Posts: 1,453
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From: CT
Good... they most likely pulled the fuse for it so that the flaps stay open all the time... which is what you want...
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS LS3, short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake, catch-can, ported/polished TB, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS LS3, short-throw shifter, NPP perf. exhaust, BMR strut-tower brace, Cold Air Inductions cold air intake, catch-can, ported/polished TB, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
Thread Starter
Heel & Toe
Joined: Apr 2023
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Drifting
Joined: Apr 2020
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From: MN
On mine the actuator hing was broken. The shop had to weld it back in place. Have no idea why that would even happen. It was like that when I bought it. Works great now.. Check that if it isn't the fuse.
Race Director
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Just because the fuse is there doesn’t mean it’s good. Replace it and see if that takes care of it.