Every housing sub-development has that one self-appointed “Noise Nanny” neighbor.
You know the one, probably by name, definitely by house location. Heaven forbid your throaty Corvette’s exhaust rubble reach her one good ear.
The Regular Production Option (RPO) listed as NPP was G.M.’s answer to the dreaded Noise Nanny for C6 through C8 owners. The NPP option is a vacuum-controlled valve on the factory exhaust, which the electronic control unit (ECU) controls.
The “nuclear propulsion package,” as we refer to it, opens the exhaust valve at the start for a few seconds, then closes so you can quietly slip out of the neighborhood.
From there, it will open and close based on RPM and throttle position. If your Corvette has the NPP option, you can easily install the “Mild to Wild” system to open or close the exhaust butterfly with the press of a button on a key chain remote.
It was an excellent solution for us until one fateful day when the fuse blew and the exhaust butterfly valve stuck in the open position on our 2013 Grand Sport.
Immediately the Noise Nanny’s evil “Eye of Sauron” gaze fell upon us, and we knew we had to act. A call to Rick Newton, co-owner of Garmon Automotive Service in Stone Mountain, got us into the shop to diagnose the problem.
Pop Goes The Fuse
Rick Newton, co-owner of Garmon’s Automotive Service, understood our “Noise Nanny” dilemma all too well. Apparently, he’s got one of his own in his sub-development.
Over the years, Rick has fixed countless NPP problems. In fact, judging by how quickly he diagnosed the problem, we’re guessing he could have fixed it blindfolded had we asked.
We didn’t, but on second thought, that would have made an entertaining video for our YouTube channel.
So, back to the problem at hand. The first obvious step in the diagnostic was to check the fuse inside the passenger side cabin.
Yes, it had popped. But unfortunately, the replacement fuse Rick installed also blew, evidenced by the melted metal ribbon and the cloudy glass encasing.
At this point, he reminded us that car fuses pop when an electrical component draws a stronger current than it is designed to handle due to a malfunctioning device.
Rick went on to say defective switches and faulty wiring are common causes for fuses blowing. Still, any mechanical issue with a motor or an electrically motivated moving part can be an issue.
At this juncture, we were crossing our fingers that it wasn’t a worn or broken wire issue between the fuse and the rear solenoid. Those usually take much longer to track down and fix.
There would have been no joy in that task. Fortunately, as it turned out, the wiring wasn’t the culprit.
Engineering Prowess?
The next step was to take out the two passenger-side tail lights to get to the solenoid. Now, you might think this would be a daunting task.
Au contraire, there is only one screw holding each tail light in place, which is either an example of G.M.’s engineering prowess or just a clever cost-saving measure. You be the judge.
I just know my C6 steering wheel looks surprisingly similar to one found on a Chevy Cobalt SS and a handful of other G.M. products of that era. Come to think of it, the steering wheel on the C3 looked a lot like one found on a Chevy Vega.
Eerie coincidence, no doubt. But I digress.
Either way, we could see the covered solenoid with both tail lights safely taken out. Inserting both hands into the tail light openings, Rick had to rely solely on experience and manual dexterity to disconnect the solenoid.
Subsequent testing revealed that the original equipment NPP solenoid had opened and closed its last. A vacuum gauge was hooked up to test the system further to ensure the mechanicals were in good working order.
The SLEEP Act
In short order, Rick from Garmon’s Automotive Services had our exhaust decibels down to “Noise Nanny-approved” levels. And how quiet is that, you might ask?
As you might surmise, we’re not a certified acoustician with lab-quality equipment. But we’ve been able to gather unofficially that at idle, standing outside of the car about 5 feet away from the exhaust with the valve closed; it puts out 65 decibels.
With the exhaust open, it’s in the vicinity of 74 decibels. Here again, don’t quote us on that, but yes, there is a substantial difference in volume and ground-rumbling tone with the valves open.
Why do we bring it up? Why should you be concerned about your exhaust decibels?
Well, New York State, for example, seeks to curb motorists and repair shops from illegally modifying the exhaust on vehicles and motorcycles to be excessively loud.
The SLEEP Act – which stands for Stop Loud and Excessive Exhaust Pollution – was signed into law by New York Governor Kathy Hochul on October 29, 2021, increasing the maximum fines and penalties motorists and repair shops face for violations related to loud exhausts.
Apparently, the “Noise Nanny” mindset has reached the state level. Is your particular state’s mandate far behind or a possible national law?
Either way, that’s a discussion for another day.
Thanks go to Rick Newton, co-owner of Garmon’s Automotive Services, for replacing our “Mild to Wild” solenoid so we won’t rattle the neighborhood.
Business Information
Website: Garmon Auto Service
5484 Five Forks Trickum Rd, Stone Mountain, GA 30087
(770) 921-7854
Email: [email protected]
Store Hours: 8 am – 6 pm Monday thru Friday
Closed on Saturday and Sunday
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