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Discussion Starter #1
Hey guys,

As some of you may know, I just picked up my first RSX a little over a week ago. Since then I have been performing a lot of maintenance including spark plugs, VC gasket, intake filter, oils and fluids, etc.

Yesterday I decided to clean the throttle body and IACV with CRC cleaner so I removed the parts, cleaned them as best I could, and reassembled all the pieces.

When I started the car up there was a loud shrill whine at idle that would seemingly go away when I hit the accelerator pedal.

I went back and disassembled everything I did the first time around to make sure there wasn't anything loose or forgotten. Everything was in its right place and connected properly.

Any ideas? Here is a video (you may want to lower your volume just in case. It's loud)

https://drive.google.com/file/d/0Bz0qO6w84Iy8MXdHTURNNk4yeGM/view?usp=sharing
 

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One thing that stands out to me is how high your idle is. Being that you were working with the idle control, and I'd take a hard look at that. not sure if the small fan in the IAC can make that loud of a noise, but you could unplug it to see if it goes away. With out the assist, it will idle poorly, but it may be quiet, and then you may know at least whats making the noise.
 

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Discussion Starter #3
Hi Marko, thanks for the advice. The idle was near 2k because it was a cold start. I can't recall if it's normally at 2k for cold start. I ordered another iacv with sensor so I'm waiting for that to come in the mail.

Hopefully the replacement solves the issue otherwise I'll have to look elsewhere.
 

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Thanks Jax! I'll look into that too. Do you know of a good lubricant to use on pulleys?
Not that I could recommend. I know some local Auto parts stores sell belt and pulley dressing (lube) which is supposed to stop squeals, but I've always stayed away from them as I've heard they cause belts to rot? Not sure how true that is.
 

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Discussion Starter #7
Ah, yeah. It's probably best to replace them. I'll let you guys know what happens when I get the new iacv.
 

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Never use belt dressings. One thing I should have asked is if it changes with RPM's. A tensioner or pulley bearing can squeal before they seize and blow apart. That sound is so loud you would think it bigger than just belt squeal. A dowl or yardstick to the ear, can pick up nasty bearing noises. Place the non ear end on hard parts (pumps, alternator, water pump) and you will hear a nasty bearing. Just some additional things before you overspend on wrong parts.
 

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Discussion Starter #9
So, my thinking was, because the sound started AFTER I cleaned the TB and IACV, it has to be one of those parts. I bought a super cheap aftermarket IACV for $30 just to see if it will fix the problem. If it does, I will go ahead and buy the proper OEM part and if it doesn't, I will consider looking at the TB and making sure it properly opens and closes.

The serpentine belt is not in bad shape but I will replace it as part of my maintenance routine. As far as pulleys go, I doubt my issue is a result of that. Before I messed with the intake side, the car idled fine (at 800rpm, except for when I turned the steering wheel so I ordered a pressure switch), didn't vibrate or make any weird noises. It was running perfectly fine in my opinion.
 

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Generally agreed. But it *could* still simply be an air leak. My vacuums and shop vacs can sound like that when the hosees are in just the right positions.
 

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Discussion Starter #11
That's very true shoegazer but I double checked that everything was tight. I guess I could have torn a boot or hose seeing as how they are old and brittle.

What's the best way to determine if it's a vacuum leak?
 

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That's very true shoegazer but I double checked that everything was tight. I guess I could have torn a boot or hose seeing as how they are old and brittle.

What's the best way to determine if it's a vacuum leak?
The only scientific method I can advise is to just apply pressure here and there, push and pull a bit, etc... and generally see if you can make the whistling change by fuxing around with a connector, hose, or clamp.

You can also grab a paper towel tube and hold it to one ear and try to localize the area. Belts and bearings are generally on the passenger side. The intake stuff is mostly on the driver's side.

You can also take a video where you hold the phone (and aim the mic) to specific areas very close up. Play it back and note where it was when it got louder.
 

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Discussion Starter #13
Haha the Brawny Stethoscope?!

Thanks, Shoe, if the new IACV doesn't solve the problem then I'll start tackling potential vacuum leaks. Realistically, I will be replacing as much rubber hose as I can.
 

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If you think there is a reasonable chance it is a vacuum leak, you can lightly spray some brake clean or carb cleaner around the gaskets and vacuum lines. If there is a leak the engine will stumble or change rpm in a noticeable way.

If you think the noise goes away when the accelerator is pressed, first manually actuate the throttle from the engine compartment. If it changes you may be able to localize the location, it also significantly reduces the number of possible sources if it is throttle position based.

Next, check if it is engine speed dependent by waiting until the engine is warmed up and see if the whistle is still there and if it is the same pitch. So if it makes noise while the throttle is set at the same position and it makes the noise at high-idle warmup and normal idle, manually move the throttle to the high idle by hand and see if it goes away.
 

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Discussion Starter #16
If you think there is a reasonable chance it is a vacuum leak, you can lightly spray some brake clean or carb cleaner around the gaskets and vacuum lines. If there is a leak the engine will stumble or change rpm in a noticeable way.

If you think the noise goes away when the accelerator is pressed, first manually actuate the throttle from the engine compartment. If it changes you may be able to localize the location, it also significantly reduces the number of possible sources if it is throttle position based.

Next, check if it is engine speed dependent by waiting until the engine is warmed up and see if the whistle is still there and if it is the same pitch. So if it makes noise while the throttle is set at the same position and it makes the noise at high-idle warmup and normal idle, manually move the throttle to the high idle by hand and see if it goes away.
Thanks One, this approach makes a lot of sense in terms of narrowing down the possibilities. I will keep this in mind during the troubleshooting.

Smoke machine. Shows leaks right away. There are DIYs out there showing how to make them.
That's not a bad idea, Bath. I'll look into doing some smoke tests when I'm getting ready to replace hoses.

The IACV replacement came in today so tomorrow I will get back in there and hopefully this solves the whine issue. I'll post updates.
 

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That's very true shoegazer but I double checked that everything was tight. I guess I could have torn a boot or hose seeing as how they are old and brittle.

What's the best way to determine if it's a vacuum leak?
Unless it is a very small leak, the idle would surge up and down once the engine warms up.
 

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Discussion Starter #18
Ok, so, I went out again and installed the new aftermarket IACV. I'm getting pretty quick at this job since I've done it so fast lol. Anyways, to my surprise, after I started the car up the noise was gone!

I was super happy - the idle was behaving normally and there wasn't anything strange about it. After I let it run for 30 seconds or so I revved it and the noise came back...

I'm thinking there is a leak between the intake manifold and the throttle body or the gasket isn't the proper shape for the inlet. I'll have to go back once again and see how the gasket sits.

If there needs to be some shaving or adjustment I'll do it, but if that doesn't solve the problem I'll have to do vacuum leak checks.
 

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Discussion Starter #19
The whine was the result of a vacuum leak between the TB, gasket, and IM. Not sure how this happened but I cleaned the surfaces of each with brake cleaner and replaced the gasket and the whine was taken care of.

Weird issue to have happen. Thanks for all the help everyone
 

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The whine was the result of a vacuum leak between the TB, gasket, and IM. Not sure how this happened but I cleaned the surfaces of each with brake cleaner and replaced the gasket and the whine was taken care of.

Weird issue to have happen. Thanks for all the help everyone
Hi there, I have a Honda Accord that is making this noise only at idle and once it's warmed up.

I had it at a mechanic and they broke it down and put it back together. It has been belts, pulled, water pump, timing belt, tencheners, a/c,

I'm at a loss..
 
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