Strange blowing/sucking air sound when in P

[thomas1984]

Hi!

I just got my car started after a couple of shitty 6 months. I can't believe the cash I paid for this car and how many problems I've got with it. Feels like an endless shitstorm. What I have done in the engine compartment is:

-Re-routed the PCV system with new hoses and PCV valve as the previoues owner installed it incorrectly.

-New sparkplugs.

-New rotor.

-New distributor cap.

-New spark plug cables.

-New choke heater tubes and gasket as the old one leaked, although all this choke stuff is not installed. The carb uses a manual choke.

-Valve cover bolts tightened, they were completely loose, all of them!

-Cleaned and tidied some cable.

Now to my question. I started her up in P and it sounds like a fan blowing air or something is sucking air. But, if I put the transmission into D or R the sound dissapeares. Strange! I have a video of the car running in P. Although, the quality isn't the best I suppose you will hear the blowing/sucking sound. Any ideas what it might be? :huh:

https://goo.gl/photos/dnSqjBdiumjo3HPv6

 

[Carolina_Mountain_Mustangs]

With the car in Park you have a faster idle so maybe you have a vacuum leak that you do not hear as much when in gear due to slower idle. Check vacuum lines for cracks or splits. The make a smoke machine to do this if you know a mechanic that has one.

 

[eddyw]

Hi Thomas,

Maybe a hint:

do you connect the vacuum throttle diafragma modulator assembly on your C6 tranny correct?

:chin:[/align]

 

[thomas1984]

Hi Thomas,

Maybe a hint:

do you connect the vacuum throttle diafragma modulator assembly on your C6 tranny correct?

:chin:[/align]

Maybe it's cracked or fallen off. I've not touched any vacuum lines for the tranny but it's worth a check. ::thumb::

I have a can of start gas I could try and gently spray around the vacuum lines. Most vacuum lines are new and fresh but you never know!

 

[kcmash]

I agree with the modulator valve theory. You should not be able to hear an air leak at idle. The modulator will make a slurping sound if it is the problem.

Cheap and quick to fix!

 

[thomas1984]

If I have a modulator with two outlets, which I've read was for extra vacuum for emission equiped engines, do I understand correct that I should hook up the line from the outlet on the side of modulator and plug the standard outlet in the middle? Darn, writing english on my smartphone is hard, I keep getting suggestions to ute swedish for all words I write.

 

[eddyw]

If I have a modulator with two outlets, which I've read was for extra vacuum for emission equiped engines, do I understand correct that I should hook up the line from the outlet on the side of modulator and plug the standard outlet in the middle? Darn, writing english on my smartphone is hard, I keep getting suggestions to ute swedish for all words I write.

I have plug off the little beside.

 

[thomas1984]

Thanks Eddyw. I'll check it out.