Vacuum Lines Diagram needed?

Ken,

Thanks so much for the quick response. I have done the, "Run the engine with belt off" - still the whine. Note: I did not remove the AC belt, but I ran it again with it wet (spray) and still the whine.
I'm working in the Driveway so I must wait for the rain to pass. I'll replace the PCV, and the Check-valve-Tee and hoses that go to the HVAC, and the belt on AC and its tensioner pulley for good measure. I'll use your diagrams to check other hoses too.
I did also have a P0171 and P0174 - bot suggest MAF needed cleaning - Did that. Also the PCV - will do that next.
Overall, the van runs fine, no idle problems - or rough on acceleration. MPG a bit down around 12-12.5 at 70 mph. [ It is a 2008 Chevy Express 2500 Roadtrek camper Van, a bit of weight on and drag too.]
Attached is a 30 sec video of the whine. I don't suspect the added Short Ram Intake, as the whine is there even with it removed! Appropriately Titled - A Most Annoying Whine!

Checking back in. I removed and serviced the Throttle Body and installed it with a fresh gasket. The photo will show a large amount of "Crud" at the 6:00 position on the throttle body. Cleaned that all off and suspect that was an easy air-leak potential for the P0171 and P0174. In a practice engine run, without the air intake installed - the 'whine" persists. Can't speak to the codes - still working the whine.
I did note that the whine persists a moment after shutdown. Does that suggest a vacuum that remains and then finishes - or? It is difficult to place its exact location. Interestingly, it gets a bit louder with the electric fans on - suggests alternator load - maybe?

I've also replaced the vacuum lines as shown (in green with a check mark) on the diagram. Some more to check. Thanks in advance! Cheers - Jim

Ken -
I wemnt out to do jyust as you have suggested. OOPS! My Express Van has a Hydroboost with no booster and check valve to pull.
Instead, we ran it again, this time with my wife under the car. She is very suspicious of the air conditioner compressor - and perhaps the idler pulley. I have a new one in hand and will install it first thing in the morning and see where we are. With that accomplished, I'll reinstall the intake etc, and give it a go. Te check codes./ At least we may have that sorted - if not the whine. We'll know in the morning.

KEN -
Thanks for the continued support! The whine persists with all belts - On - or Off. A/C and main serpentine belt - either on or off the engine.
Yes the Air Intake is an after market - but the whine is there with it On or Off.

As I continue to chase this whine, I came upon an idea. My plan is/was to use an inflation technique.
1. Close the off the throttle body
2. Add small pressure to the system
3. Escaping air could be found using soap solution.

Using a small hand transfer pump, and a rubber glove, I pumped up the glove (attached to the throttle body).
My observations:
1. I was able to pump past the butterfly. (Engine not on).
2. The glove deflated in under 20 seconds.
A couple of thoughts came to mind. Should the butterfly be "air tight" when closed? If not, that explains how it filled.

Then, as it deflates, can I correctly assume, that excess pressure (very small) is escaping through a leak? Or, is it bein distributed through the open/partially opened valves on the cylinders?

I am considering using a small compressor (tire inflator) to apply continuous pressure at one of the vacuum ports and chasing leaks with soap. Bad idea? What pressure would be OK? Or, I can fabricate a coer for the throttle body and apply the pressure there and use the soap. Your thoughts are much appreciated.
Thanks.