C6whinnit

Hi all,
Not sure if this question has come up before, did search but couldn't find anything.
When i start the car in the morning the exhaust sounds normal, but after sitting during the day i start up and the baffles are stuck open after about 15 minutes of driving the exhaust goes back to quiet mode.
While i love the loud exhaust it has me as to why it does this. It seems to happen after the car is sitting out in the heat all day, pressure builds up? This has just started happening.

Thanks in advance.

RicK T

Sounds like a vacuum leak somewhere. Just start at the actuators on the mufflers and trace as much as you can but it may be a leak in an inaccessible area.

GaVette61

This thread has a schematic of the vacuum lines: https://www.corvetteforum.com/forums...ed-closed.html.

The line runs from the back of the intake manifold to the solenoid in the rear bumper. Good luck. I had a problem but mine was only the solenoid valve.

C6whinnit

Thanks, i'll take a look this weekend.

madmatt9471

Try triggering the baffle with a pen or your fingers when it has been sitting in the sun to see if they are Sticking -

My thoughts are that if it was indeed a vacuum leak it would stay open all the time - you can check either way and use a vacuum pump on the lines to ensure there are no leaks, plug the opposite end.

Perhaps, by sitting in the sun it is heating up the NPP module and not allowing it to function properly - if at all possible try sitting it in the shade and see if the same thing occurs at the end of the day -

Keep us posted on any findings - then we'll move onto the next step

Thanks,Matt

C6whinnit

Thanks Matt,
It definitely appears that it only happens when the car has been sitting all day in the sun i get this issue. I'll see if i can find a shady spot and see what happens. Will also check to see if the baffles are stuck as well.

Thanks

Kevin

C6whinnit

Baffles move no problem manually whether hot or cold, I have put the car in the shade later in the day and it definitely makes a difference. Out in the sun all day exhaust is loud, in the shade normal sound.