Chasing down intake whistle (SOLVED)

jeep_boss

jeep_boss

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My Jeep is producing a whistle noise between 1800 and 2400 RPMs. I suspect that it is coming from my theottle body / IAC, as it wasn't present prior to me cleaning it a couple of days ago.

The best way that I can describe this whistle is (on the 4.0L motor with a CAI), the air sucking noise that the intake makes when you punch the accelerator - this whistle is like an exageration of that sound note.

The audio does not pick it up when I record video.

I did buy and install a new TB gasket. The only thing noticable different would be the orintarion of th aluminum booster block thing (name escapes me) that bolts underneath the TB - it's seated 90 degrees CCW from where it sat before. There is threading inaidenof that aluminum block exposed to incoming air, however, I don't see how that would influence this whistling noise.

All of my new exhaust manifold bolts are secured too.

What do you guys think? I can't figure out what could have changed after cleaning my TB, so I'm scratchng my OCD driven head trying to find the source :/
 
cliffish said:
Yeah...I almost would be lighting the molotov cocktail by now!
Click to expand...

Trust me, I have been close!!!

Whistle is pretty much gone now. I disassembled and reoriented the aluminum lifter block back to where it was. Now it just sounds like it used to. There is that faint intake sound kind if like an old VW Beetle, but it is just what I have thought to be a normal happy 4.0L noise.
 
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I had a whistle similar to what you describe. I noticed a vacuum line was missing from a nipple on the intake manifold. The line comes very easily so maybe give that a look. May or may not help but this forum helped me out a bunch, just trying to pay it forward.
a3bf893ba18a0bff3b62432eba2c354e.jpg


Sent from my SAMSUNG-SM-G891A using Tapatalk
 
I had a whistle similar to what you describe. I noticed a vacuum line was missing from a nipple on the intake manifold. The line comes very easily so maybe give that a look. May or may not help but this forum helped me out a bunch, just trying to pay it forward.
a3bf893ba18a0bff3b62432eba2c354e.jpg


Sent from my SAMSUNG-SM-G891A using Tapatalk
 
ridinsurf66 said:
I had a whistle similar to what you describe. I noticed a vacuum line was missing from a nipple on the intake manifold. The line comes very easily so maybe give that a look. May or may not help but this forum helped me out a bunch, just trying to pay it forward.
a3bf893ba18a0bff3b62432eba2c354e.jpg


Sent from my SAMSUNG-SM-G891A using Tapatalk
Click to expand...

My issue was different and involved the throttle body and/or IAC. Although I recently replaced my vacuum line, I'm the one that pointed you to your passenger side battery area ;-)
 
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I have a whistle also ..it will come and go ....when I open up the throttle body by accelerating it will go away when it happens ..i have also tried tightening the intake no help ..
 
ridinsurf66 said:
I had a whistle similar to what you describe. I noticed a vacuum line was missing from a nipple on the intake manifold. The line comes very easily so maybe give that a look. May or may not help but this forum helped me out a bunch, just trying to pay it forward.View attachment 112929

Sent from my SAMSUNG-SM-G891A using Tapatalk
Click to expand...
Where does that vacuum line run to mine just went missing
 
Dealing with a whistle after the engine heats up or about 5-10 minutes of driving.

Wheezing whistle appeared after installing aluminum KN air intake. Hose clamps bent the aluminum; aluminum didn't seat properly in filter; rough edges on aluminum mating up with throttle body. Fixed all of those issues with a tube of gasket maker and some aftermarket tubing/hoses.

Sharp whistle appeared only on deceleration, down to 1500-2000 rpm then stopped. Or, whistle went away after revving in neutral or park at stop lights.

Replaced PCV valves and connected hoses. If the PCV valves shatter or require a Dremel to remove, just buy a Dorman valve cover from the parts store. Saves time and effort for WJ owners like myself.

There's an idiot on YouTube I followed advice from that said to replace the tubing with clear reinforced tubing bought from Lowe's/HD. Garbage advice. That tubing is rated for low temp high pressure. Warped under the hood. Replaced with tubing from auto parts store.

0.5" for PCV valves. 0.5" connects to KN aluminum piping. Will need the Dorman valve tubing kit that has a 0.5" to 0.25" tapered hose connector and a 0.25" to 0.25" connector. Run a short 0.25" tubing between the tapered connector and the 0.5" tubing off the back PCV valve. The tapered connector can be forced onto the metal nipple on the intake manifold. I put hose clamps on the PCV valves, KN nipple, the joiner and the connector to eliminate the whistle.

New whistle appeared. Three vacuum nipples on the side of the intake manifold were warped or lose. The nipples vary in size: 0.25" , 0.3125" , and 0.375". These nipples lead to other components via brittle plastic tubing connected with various size hose connectors. Just buy 3-5 feet of 1/4, 5/16 & 3/8 tubing to eliminate the plastic pipe-tubes. Completed these three. Whistle stopped for a day.

Whistle reappeared, somewhere on the driver's side, around the intake manifold again. Sounds like it's between the valve cover and throttle body but closer to the firewall.

Lost on next step. Have heard some say it's a failure of the metal gasket between the exhaust/intake and head. There's no way to test this with WD-40 much less reach around all components on a WJ. I realize this is not a WJ forum but the engine is same or similar up through 2006 in the Wrangler. Solutions should be similar.

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jeep_boss said:
My Jeep is producing a whistle noise between 1800 and 2400 RPMs. I suspect that it is coming from my theottle body / IAC, as it wasn't present prior to me cleaning it a couple of days ago.
Click to expand...

It's funny how these old posts are the gift that keeps on giving! It had a whistling sound, and, it was generated by more than one issue, in my case, it was just the Throttle Body Gasket. Interestingly, I found a Throttle Body space for 38.00 on Amazon warehouse that came with gaskets, so I was like what the heck, even though I'm skeptical about that stuff. This is insane, but on our 4.0L Automatic, it made a HUGE difference in throttle response from a stop. I mean big time! It also helps to get on the interstate.

You can distinguish between the "Winter Whistle" and the throttle body sound.


 
Actormike said:
It's funny how these old posts are the gift that keeps on giving! It had a whistling sound, and, it was generated by more than one issue, in my case, it was just the Throttle Body Gasket. Interestingly, I found a Throttle Body space for 38.00 on Amazon warehouse that came with gaskets, so I was like what the heck, even though I'm skeptical about that stuff. This is insane, but on our 4.0L Automatic, it made a HUGE difference in throttle response from a stop. I mean big time! It also helps to get on the interstate.

You can distinguish between the "Winter Whistle" and the throttle body sound.


Click to expand...

I assume the spacer is providing you with results = to results that were previously achieved by pushing the gas pedal down further.

A $4.00 fel-pro gasket would have solved the whistle, but if you're happy that's great.
 
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