[smokingv6]

Hi, I have a 19 SS all stock, except i just had a muffler shop delete my muffler and the 4 npp valves . Sounds great, but after 21 miles of driving the check engine light came on. The electronic portion of the valves were unbolted and ziptied out of harms way, and are still plugged in. (Code P12ea) Maybe I need to unplug them to make the
light go away? Ive heard everyone on here say that should not turn cel on. I try to clear code but it stays on. Please advise

[WhiteMale]

There are 2 NPP valves, it sounds like they pulled the AFM valve's in the midpipe which you cannot do w/o throwing codes.

[ember1205]

Originally Posted by WhiteMale

There are 2 NPP valves, it sounds like they pulled the AFM valve's in the midpipe which you cannot do w/o throwing codes.

Yep. The two that are partway through the exhaust and NOT connected to the muffler are required for the AFM to work correctly. Either those need to go back on, or AFM now has to be tuned out. Additionally, the valves need to be wired to the harness, still, or the car will throw codes for other reasons.

[cellsafemode]

Originally Posted by ember1205

??? Wrong thread?

Wow, very wrong thread. not sure wtf happened.

[ember1205]

Originally Posted by cellsafemode

Wow, very wrong thread. not sure wtf happened.

I mean... going electric COULD be a way to delete a muffler.

[cellsafemode]

Originally Posted by ember1205

I mean... going electric COULD be a way to delete a muffler.

depending on how frequently you get ticketed and potentially worse by the police (or whatever may happen due to annoyed neighbors) for your loud exhaust ...it might even be a cheaper way to do so.

[smokingv6]

Thanks for all the responses. I may get those 2 put back on. They seem like they don't restrict a whole lot compared to the almost flat sections that I removed due to clearing the extra bars for my convertible. At the same time, I will also add electric cutouts right before the secondary converters. Noise is not an issue with me or my neighbors .

[smokingv6]

Originally Posted by WhiteMale

There are 2 NPP valves, it sounds like they pulled the AFM valve's in the midpipe which you cannot do w/o throwing codes.

Do they sense a flow, or monitor back pressure somehow?

[Mark114]

Originally Posted by smokingv6

Hi, I have a 19 SS all stock, except i just had a muffler shop delete my muffler and the 4 npp valves . Sounds great, but after 21 miles of driving the check engine light came on. The electronic portion of the valves were unbolted and ziptied out of harms way, and are still plugged in. (Code P12ea) Maybe I need to unplug them to make the
Iight go away? Ive heard everyone on here say that should not turn cel on. I try to clear code but it stays on. Please advise

You may need to install these on the AFM valves in the center of the exhaust or tune AFM out. Search through the exhaust subforum to see what others have done.

https://www.awe-tuning.com/news/awe-...d-c7-corvette/

[ember1205]

Originally Posted by smokingv6

Do they sense a flow, or monitor back pressure somehow?

When the ECU is dropping the motor down to 4CYL mode, those get closed to create additional back pressure. If they are removed, the computer will throw codes due to lack of back pressure in 4CYL mode.

The flat sections of the exhaust create no appreciable difference in the back pressure that affects how the motor runs.

[smokingv6]

Originally Posted by Mark114

You may need to install these on the AFM valves in the center of the exhaust or tune AFM out. Search through the exhaust subforum to see what others have done.

https://www.awe-tuning.com/news/awe-...d-c7-corvette/

Update....I added 2 AWE brand AFM simulators , and drove 23 miles, seems to be ok so far, fingers crossed.

[lt4camaro]

You need the simulators that bolt on to the electric motors that are ziptied to the underside of the car. Cut the zipties, bolt on the simulators and re ziptie to the undercarriage.

[smokingv6]

[QUOTE=lt4camaro;11224901]You need the simulators that bolt on to the electric motors that are ziptied to the underside of the car. Cut the zipties, bolt on the simulators and re ziptie to the undercarriage.[/QUO

I did that, seems to be fine so far....