A Most Annoying Wine...

[phantomjock]

Not the kind in a Box... but a WHINE under the Hood.

Looked in all the forums. Not the under pax seat alarm. Not an "alarm." The engine must be running. No change with RPM. No difference AirCon On/Off. More obvious with the electric fans off - but still there either way.

Replaced the Tensioner Pulley - even lubed with lithium grease - noise remains. Replaced the belt - no change in the whine. Belt is tight and doesn't appear to be slipping.

If you want to hear it - it is in the ZIP file attached an mp4 file. Fortunately (for me) it is just at the top end of my range, so not so annoying - but,
I DO hear ABOUT it...

Thoughts? Suggestions. All welcome. TIA.

Cheers - Jim

[booster]

Engine running but not rpm dependent is a pretty off combination and eliminates most stuff it could be.


The climate control fan is right there, and they run it all the time that there is any selection other than totally off on dash control so that might be possibility. Motor can make some odd noises, as can fans with "stuff" in them. The dampers are also controlled with gear motors for the most part, also.



If the bypass of the hydroboost was slightly open in might also make some noise.

[phantomjock]

booster -

Some good ideas for me to checkout. The whine "seems" to be on the passenger's side - but audible through the entire bay. Your thoughts on the climate fan would make sense - it is on the right side - yes?

I'd think the hydroboost would be more obvious on the driver's side.

I'll keep digging! BTW - a mechanic's stethoscope was no help!

Thanks.

Cheers - Jim

[phantomjock]

Small Block Chevy (SBC 350-383) has been my forte. I'm diving into the engine (bay) and surrounds getting a bit acquainted with the 6.0L LS in my RT. This started out chasing a high pitch whistle. SO far:
It is NOT:

1. The tensioner pulley [replaced]
2. The Idler wheel [also replaced], or
3. The Belt.

I did a short run with the belt off, and the whistle/whine persisted and was consistent in pitch and volume regardless of throttle position. The air conditioner pump belt was still on. It has been replaced as a matter of PM.

Now, I've removed all the bits in the engine bay [battery, coolant overflow tank, belts, etc] and disassembled/removed the interior engine cover. I now have access to a vacuum port on the aft right (passenger's side) of the Intake manifold. Looks nothing like any of the pictures I've seen. The line does go to the "T" that then connects to the Vacuum Reservoir, and the airbox controller. NOTE: this image is not "Exact", but representative.


I'll replace the vacuum lines and the "T" check valve. Picture




In my checking things out, I saw this:


It looks like it "should" have some type of hose on it. The end is barbed. It is located on the right side of the engine - facing forward, just adjacet to the fuel rail and the coil over plugs. It almost "looks" as it should have a fuel line attached to it.
What is it? Any guesses? Should it connect to "something?" What?

Anxious for suggestions or comments.

TIA.

Cheers - Jim

[phantomjock]

OK -

Did a bit of sleuthing. Still not sure what the fitting is for:


But there appears to be an opportunity to add a Fuel Rail Pressure Sensor to the opposite side:



That schrader valve is on the opposide rail - shown vertical in the drawing.

The mystery fitting definately is part of the fuel rail system. But why - still unsure? If nothing else, it looks as if it should at least be covered.

Waiting for the Tee Check Valve to arrive tomorrow. Do some reassembly and check for wine!

Cheers - Jim

[booster]

I haven't dug into any of that on our 07, but on the 96 Buick 350 the fuel rail has a Shrader valve on it also. The factory service manual says it is for relieving fuel pressure if needed to service things that are pressurized and also to connect a fuel pressure test gauge. I have used the fitting for both functions.

[phantomjock]

Thanks booster!
Were your fittings covered?
Just seems to be something that might make sense.

Cheers - Jim

[booster]

Originally Posted by phantomjock

Thanks booster!
Were your fittings covered?
Just seems to be something that might make sense.

Cheers - Jim

Mine did still have a cover on it, but from what I hear on the old GM station wagon forum I am on most of them on vehicles are missing. It is just a plain old tire valve cap like on vehicle or bicycle wheels. I have a whole drawer full of various versions of them. The factory on that was on it, if it was factory still, was just like you see on lots of tire valves. Maybe a skull one would look nice.....

[phantomjock]

Isolated, odd location, difficult to see. I'm thinking maybe a flashback to the60's;

"Have a Strange Day"



Cheers - Jim

[phantomjock]

I MAY HAVE neglected to include ALL the facts in my earlier posts. The whine under the hood was also accompanied with a Check Engine Light. It was throwing Codes P0171 & P0174. These both are indicating the 2 banks are running lean.

These codes could occur if the MAF in the intake is dirty - or a vacuum leak aft of the MAF. The situation can also occurr if there is a crack in the PCV valve tubing or a stuck open PCV.

fIRST PRIORITY - I cleaned the MAF, aNd did a test run. Still a whine. I then removed the entire intake short ram from the engine. With a test run - same codes and still that annoying whine. The MAF may not be the source of the Codes! But what about the whine? The same source?

I removed the belts and did a short run of the engine. I confirmed the whine was NOT from Pulleys, Belts, or Driven Accessories. None-the-less, I replaced the tensioner and idler pulleys for good PM, and the belts also.

Next attack - Identify and find all the vacuum lines and begin an inspection and test of each and the full system.

Finding a good picture of these is not easy. The Express Van 2500 shares similarities with the Silverado, and Astro Series and even the Safari. There were some diagrams under these models - but few specific to the Express 2500. Best I could find was this one:


First and easiest to work was the check valve and vacuum test the reservoir.


Easily done, but when I put pressure on the system - it didn't pump up. There was definately a leak - still.


That led me to the PCV as a good posibility.


Access is not easy. Removing the passenger seat made it easier to then remove the interior engine cover.

It appears that the Chevy LS 6.0L May NOT actually have a PCV. It has a ported fitting in the aft of the left cylinder head cover - but it "just looks" like a PCV. Looking inside, it appears to be empty inside - just a small hole at the base - and impossible to remove from the head.

I removed then checked the hose/tube under water with pressure and capped off. And - yes, a leak at one of the hose ends. Now a new part is on order. I could just buy new hose ends, but a new item adds a bit of confidence. Once tested before installation!

I've been in contact with one of the online "Help Forums." (Specifically, 2carpros.com) There is a suggestion to consider replacing the Throttle Body Base "O" Ring. What the heck. The engine bay is getting pretty empty, and the new PCV hose doesn't arrive for a few days. And the local parts store has an O-ring in stock.

The only problem with loading up the Parts-Cannon - then firing... you never know what fixed the problem!

More to Come.

[booster]

Do you have a way to read the fuel trims? That might give a clue to codes being thrown. Low fuel pressure comes to mind right offhand, especially if the trims are on max added fuel allowed and still running lean. O2 sensors would also not be switching constantly and would be locked on lean voltage.


Not a lot of stuff affects both banks. MAF sensor, idle air motor if it uses one, fuel pressure, injector voltage, throttle body stuff, EGR if it has one. Intake manifold leak, primarily in the rear of the intake to block IIRC.

[55 Nomad]

I have a 06C190V with 6.0 engine that i had those same codes. Lean fuel mixture on both banks. Went thru the compete intake system and no leaks found. I did find my oil fill tube was not fully installed in the valve cover grommet. Properly installed oil fill tube cleared codes and they haven't returned in over two years.

[phantomjock]

55 Nomad;
I did find my oil fill tube was not fully installed in the valve cover grommet. Properly installed oil fill tube cleared codes and they haven't returned in over two years.

I've seen that obscure reference in my sleuthing. Do you recall hearing a "whine" too- or whistle?


booster - once I reassemble and do a run, I'll check for the Fuel Trim. Might be stored. I'll take a look. Adds anther range of issues - fuel pump/regulator/filter. Oh Joy!


Cheers - Jim

[booster]

Originally Posted by phantomjock

I've seen that obscure reference in my sleuthing. Do you recall hearing a "whine" too- or whistle?


booster - once I reassemble and do a run, I'll check for the Fuel Trim. Might be stored. I'll take a look. Adds anther range of issues - fuel pump/regulator/filter. Oh Joy!


Cheers - Jim

Your fuel trims should be stored as long as the battery has not been disconnected. It would the long term fuel trim (LTFT) that would show what you need.

[phantomjock]

Thanks -but I have been disconnected for a couple of days - so no luck gettint the codes I suppose.

55 Nomad: Was that just a push into place - twist to tighten - or a full-on remove and replace? I see several variations on that operation. I'll check after breakie!

Cheers - Jim

[phantomjock]

55 Nomad - Thanks for the idea. But I was grasping at straws and wishfully thinking...

All 3 are tight and no movement; Oil filler port, Oil Dipstick, and Transmission ditstick.
Next stop; LAPS for a gasket and pull the throttle body. Still waiting for the PCV hose/tube to arrive.

Ain't Hot-roddin' Fun!!

Cheers - Jim

[55 Nomad]

No, I don't recall a whine or whistle. The oil fill tube is a push in and mine was not inserted correctly allowing air to enter the engine. I don't know how that would affect the fuel trim but when I correctly installed it the fuel trims went from maxed out lean to normal. I hope this helps.

[phantomjock]

Thanks -all three seem solid in their mounts. I'm waiting on parts... My just get some tube/hose to connect the PCV to the block and reassemble. Then I'll give a pressure/vacuum test before firing up.

Meanwhile, replacing the hood latch and cable. RockAuto just dropped off my new bug screen - last one on close out. (OOPS - cross post.)

Cheers - Jim

[phantomjock]

R&R the Throttle Body:

Found a ring of "crud" along the bottom:


Cleaned it all up and looked much better (this is the top - bottom is as clean now):


Re-installed with new gasket.

Dug around the engine with the interior cover off and located this Vacuum Port (I've seen it referenced for use with Cruise Control Units, Brake Boosters, etc - but nothing on my engine):


Any ideas?

In summary here's where I've been: (items completed checked off):


Reattached the belt, and fired up.
Whine remains. More frustrating than annoying. Noted that it persists momentarily when the key is shut down. Then quits. More noticible with the fans on than off.
[Does this suggest load on the alternator? No difference with foot on brake/off, or A/C on/off. Most puzzeling.]

I'll work codes tomorrow Need to reinstall air intake for full test.

Cheers - Jim

[phantomjock]

The whine persists with all belts - On - or -- Off. A/C and main serpentine belt - either on or off the engine. The whine persists with the new throttle body gasket installed. Even there with the air intake 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?

LINK:
https://youtube.com/shorts/uI6zvz1aY6s

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 cover for the throttle body and apply the pressure at the intake and use the soap.

Comments and thoughts are much appreciated.

Cheers - Jim