lwise4

When I got this car both flappers were open.

I finally got mine to close the flappers by replacing the fuse that the previous owner had pulled and reattaching a vacuum hose that was pulled off of one flapper.

I now have a mild to wild setup with remotes and it will not work! I pulled it back off and left the fuse out and the flappers remained closed!

I thought that pulling the fuse would open them up?

Does anyone have the circuit layout for this system?

I drove the car on the highway today and with the fuse out 3500 RPM did not open! With the fuse in 3500 RPM did not open! As I mentioned, when I got the car both flappers were open and would not close but there was no fuse and there was a vacuum line off of one of the flappers. As soon as I hooked up the vacuum line both flappers closed. I ordered the Mild to Wild and it will not activate the flappers. There is a link in the next response that I will study this week.

RicK T

I don't have the circuit diagrams. Post 9 in here gives the SM troubleshooting process for most of the system. It might help.

https://www.corvetteforum.com/forums...post1579920143

1pt4brd

Am I going to run into extreme problems if I get to have the NPP installed? I found one for sale. Not going to be available for a few months.

lwise4

I have no idea. I bought my car with it already equipped! I am just trying to get it working!

K9KUZ

Curious about the price...I put the NPP on my '05 without any problems. But paid a bunch - $900! ouch.

1pt4brd

Not sure about price. Guy selling is still using. We will discuss price when he has it off.

RicK T

It's generally an easy, straight forward swap.

But there is a compatibility issue. GM slightly changed the angle of the passenger side pipe in '09. So if your car is an '05-'08, the only NPP system that is a straight PnP swap is the '08 set. If your car is an '09+ then you would need an '09+ NPP set.

You can mix different years by also swapping the x-pipe.

Russkier

Change the batteries in the remotes, they only last a year or two.

lwise4

The batteries are good. Troubleshooting is with the last page of the installation instructions. The unit is new as are the remotes.

GaVette61

I really don't know what your problem is but I know if you pull the fuse or the solenoid goes out, the open position is sort of the default. Being closed and never opening doesn't make any sense. Did you ever get a response from the M2W vendor?

LMB-Z

Make sure you are getting vacuum at the switch behind the passenger side tail lights. Mine was not working until I replaced this. Can't remember exactly what its called.

IDSRVIT

Was the car running when you reattached the vacuum line that was off? That would be the only way the flappers would shut since they need vacuum to close.

The NPP circuit I believe is pretty simple. I've never actually played with it but, the vacuum I know comes from the intake manifold and goes to what I can only assume is some type of electric solenoid monitored by the computer. Once the engine hits 3500 RPM the solenoid shuts off the vacuum to the NPP valves and the baffles opens which gives you the extra rumble.

If you're fuse is connected (make sure you verify the fuse is good) and the Wild2Mild is connected properly and still not working then I would check the solenoid next.

KyJim

sounds like the exhaust solenoid needs to be replaced. I have attached a pdf of the valve and its location

YLOC6

Yes with the fuse out they are OPEN 100% of the time AKA "Wild" replacing the fuse should close the inbound pipes until you reach 3500 RPM. I remember before I removed my fuse mine would "stick" in the closed position.
I'm thinking of installing a "Mild to wild" switch soon.

MH663

weathermaker

Before you installed the M2W the flaps were closed and did not open. Correct? So, if there isn't vacuum at the flaps and they are closed, then the flaps are stuck. Try to move them with your hands to see if they move freely. If you have vacuum there all the time then it's the solenoid, possibly.

lwise4

Yes I did! His response was "the installation looks good". I emailed Him this morning and asked what's next?

lwise4

I ran the car up to 4000 RPM's a couple of times today and the flappers did not open! As I said when I got the car the flappers were open all of the time. The fuse was removed and a vacuum line was off of one of the flappers. I replaced the fuse and the vacuum lines and now the flappers will not open at 4000 RPM nor would they open with a mild to wild installed?

I don't think it is a good idea to remove the hose line as I am sure that is the same as a vacuum leak? Is the absence of vacuum to the flappers what opens them?

IDSRVIT

As several of us have noted, the only electrical component is the solenoid which sounds like it's not working. Have you checked that?

lwise4

I have not. I just printed out the picture that another kind forum member posted. I will look at it post haste! Thanks for the reminder!