VQ35DE loud whining/teapot sound

T

tchuck

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Wow, so I just finished buttoning up the engine bay on FX#2, and upon startup its idling at 3k rpms and I'm hearing this crazy loud whining sound. It actually sounds like the supercharger is still installed. I thought the crank pulley could be rubbing against the outer timing cover but after removing the belts and crank pulley the noise remains. It is rpm dependant and does not appear to be getting worse over time. (I've only run it for maybe 2min total)

Here's a sound clip. It's louder than it seems in the video...
https://www.youtube.com/watch?v=L-nQ2L-oi_0&feature=youtube_gdata_player

Here's the breakdown of what's happened with it over the last few months:

1) It had a Stillen stage 4 supercharger, with 440cc injectors, a walbro 255 fuel pump, and a custom tune by technosquare. The motor was quiet as a mouse when I drove it into my driveway.

2) Supercharger, injectors, intercooler, oil cooler, crank pulley, trans cooler, N2o cooling kit, and headers were removed.

3) Stock injectors, intake plenum, and exhaust manifolds were installed. Throttle body was cleaned. Ecu was reflashed with the "back to stock" rom from Uprev.

The noise is so loud its hard to pinpoint, but if I had to guess I'd say it's coming from the timing cover area.

Thoughts? Comments? Jokes? The only thing left to do is fix the driver's door and I can get this thing out of here. I'm not stoked about this turn of events. :(
 
sounds like an air leak. are you sure you put on all the hoses in the back of the plenum? what about that gasket thats under the lower plenum did you put that back in?
 
I'm going to pull the plenum right now but I really can't imagine that's the issue. It sounds like a train screeching to a stop. I'll update in a couple hours.
 
If you give a little gas does the noise go away? this happens only when the engine cold?

and for a vacuum leak get a spray can of carb cleaner or spray bottle of water. Carefully spray around all the things vacuum related. If the idle changes while performing this test, your know where your problem be.
Check your idler pulley and alternator
 
I never pressed the throttle while the engine was on. It was already idling at 3k rpm - I didnt want to push it on an ice cold motor...

Too late for the carb cleaner trick...
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y4a9u9at.jpg

I'm going to reassemble the plenum with new gaskets (I reused the old ones before) and eliminate an air leak from the list of possibilities.

Also, I removed the crank pulley and the noise remained.
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apejumas.jpg
 
Sure sounds like vacuum/air leak. There are a bunch of different hoses so it's not hard to forget one or not quite get it on right. I think my stock plenum gasket also got bent during spacer installation, so that's another thing that can happen fairly easily.
 
wow, that was going to be the first thing i'd say, remove the damper and run it with no belts, hopefully it is just an air leak, hard to really tell from the video but on my laptop it sounds really cool, like a jet idling up on the tarmac :)

if it's still there and sounds like it's coming from the timing chain area you can use a long screwdriver like a stethoscope, just press the handle to your ear and the end to different areas to try and localize the sound.
 
Well, if it was an air leak it's gone now. It's too late to test it now but I just pulled the plenum assembly off, cleaned all the mating surfaces...
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teba7y7e.jpg
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...applied a thin film of RTV sealant on both sides of the new gaskets...
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pu5e2a5e.jpg
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...and put it all back together.
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ryzyze8u.jpg

I'm not sure if I'll get a chance to fire it up before tomorrow evening but I'll update this when I do. I should mention that part of the reason I don't think it is an air leak is the volume of the sound. It's REALLY loud. Like significantly loud than the blower was at full steam. Crazy loud. It also doesn't sound like air to me. It sounds like a train stopping in a hurry. Metal on metal sound, not a whistle. That said, I've never heard a sound like this one...

And finally, as if starting the whining wonder three or four times around dinner time wasn't annoying my neighbors enough, at about 10:30pm I leaned over the radiator, squishing the keys in my jacket pocket. This A) started FX#1, and B) set off the panic alarm on FX#2. My head was probably 16" from the horn at the time and it took about 30sec to shut everything down. Good times.
 
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All the air hoses were/are plugged in, and I'm happy to report that after replacing the old gaskets the noise is gone! I am seriously shocked that an air leak could be that loud, but I guess that was it. I did notice that, unlike the gasket between the upper and lower plenums, the gasket between the lower plenum and upper intake manifold is not a reusable (flat) type but rather a crushable one time use type. Note to self...

Thanks dudes!
 
:good:Good to hear it was a simply air leak. Which gasket causes the leak?

Hmm curious why you think the metal gasket between the lower and upper plenum is not re-usable. I did not have any problem reusing it with the Crawford plenum swap and then reuse it again to swap it back to the stock plenum. Must be my luck!
 
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Yeah, I replaced that gasket with the MD iso-thermal one. I don't remember the stock one, but the MD one you are supposed to soak in oil, and it's a bit thicker like it relies on pressure to seal correctly.
 
la_fx35 said:
:good:Good to hear it was a simply air leak. Which gasket causes the leak?

Hmm curious why you think the metal gasket between the lower and upper plenum is not re-usable. I did not have any problem reusing it with the Crawford plenum swap and then reuse it again to swap it back to the stock plenum. Must be my luck!
Click to expand...

Between upper and lower plenum - reusable.

Between lower plenum and upper intake manifold - not reusable.

I'll take some pics when I get home.
 
Ok good, I originally understood, then got confused. Is the non-reusable one thicker? I feel like I remember seeing an outline in it from getting crushed.
 
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