Whistle under hood

[sunbum]

I have the KKM air induction kit installed and am quite happy with the results but I do
have a question:
It seems that from ~2000-2500RPMs when stepping down on the gas, I'll get a lil whistle from under the hood, whether it's at 45mph or 70mph. It's just when I'm in that range and pressing down/in the first inch or so on the accelerator. Otherwise, it is quiet under there.
Any clues what's making the noise? I've recently oiled the filter and ensured the seal was tight, so that shouldn't be the problem.
Felsman has a 97 and also noticed this in his and he doesn't even have the kit, so I'm not sure what it is... help us? Dead Link Removed
Thanks in advance.

[This message has been edited by sunbum (edited 01-14-2000).]

[This message has been edited by sunbum (edited 01-14-2000).]

 

[Gopher]

i've heard of a lot of people having this sound when they have a throttle body that was bored out. Could be the throttle body..just a thought..If you ever purchase a larger throttle body, buy the BBK 66mm. Alot of the others you see are stock bodies machined out and these are the ones that give you that whistling sound.
Brian

 

[RVerdejo]

My 96 EB V8 started doing that after I cut two 1.75" holes in the air filter housing. Turns out it was the air bleed hole in the throttle plate...extra airflow made it whistle when under very light accel.

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Don't Worry about things you can control...
Don't Worry about things you cannot control.

96 Eddie Bauer AWD V8
Two other cars that aren't Explorers

 

[Jac78]

I installed the KKM tru-rev kit a few weeks ago and noticed a sort of "whistle" too. I get the whistle in and around 4th gear when I'm really stomping down on the gas pedal.

As far as I know it comes from the fact that the air filter is now exposed. I knew ahead of time to expect "noises" from the intake, because friends have open air filters in their import "racers".

You may have also noticed the noise that sounds like the air-filter is taking a "gulp" of air when you hit the accelerator. I wouldn't take the whistling as something wrong! Dead Link Removed

~Jorge*
92 XL V6 4X4
Flomaster Exhaust
KKM Tru-Rev

 

[raven2]

I had a whistle under the same conditions on my 91, but did not have any mods made, my whistle turned out to be the bearings in the altenator.

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91 Sport

 

[mikefox]

I also have this condition in my '95. The only mod to it is a Dynomax cat-back system. I have been waiting to buy the KKM kit. I don't have any idea what could be causing the whistle type noise that only seems to happen around 2000-2500 rpm at any speed and only under load. If you are in park and rev it up I don't hear it at all. Will have to do some more checking. Maybe power braking it might cause it to make the noise and then I can pin point it out. Other than that I love the vehicle. Dead Link Removed

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mike fox
95 XLT 4D 4X4

 

[sunbum]

Thanks for all the great replies... I guess it's nothing to worry about then, but it's odd that I didn't notice it until I put in the KKM, though others without are saying they they get the whistle. Interesting.
I guess the answer is to get larger tires so I hear a hum instead of a whistle. Dead Link Removed
I tried to fix my formatting in my orig post to save lines, then it shows a new line for each edit I did. Oy. Dead Link Removed

 

[LukeDog3D]

Check your air tube for small holes or cracks. I had the same problem on my '92. I think the air tube was a bit brittle from age and heat, and when I installed my kkm, I had to wiggle the tube around, which made two small cracks at the flexible part near the throttle body. It would whistle as you described. I found the cracks a few days later and sealed them with silicone.

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[Paul Gagnon]

What you are probably hearing is normal intake noise. When the air rushes into the engine it makes noise as it goes through the intake tract. The noise is always there on any car. Normally it is not too loud because of the design of the stock air cleaner box. They are designed to be quiet, which is also what makes them restrictive.

With your new open element filter you will hear all kinds of intake noise. It is the price that you pay for a higher flowing air cleaner.

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Paul Gagnon
Calgary, Alberta
"No Brain, No Pain"
Dead Link Removed

 

[felsmann]

Well, I can tell you all that the noise is there without any modifications. I have had this for months and thought it was normal. It started after the RETARDS at the Ford dealer serviced my throtle body.

I just installed the K&N Injection Performance Kit and the noise is now a little loader, but still only apparent on those pedal ranges mentioned by you guys.

Another For service F*** up that we have to live with.

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Juan Felsmann
'97 Sport 4WD
Warrior Twist

 

[felsmann]

So did we ever figure out how to fix this problem???

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Juan Felsmann
'97 Sport 4WD 5spd
Warrior Twist
www.explorer4x4.com/thaven_juan.jpg

 

[gerry]

I started noticing a whistle on cold mornings, a couple of minutes after start-up.

Mine was different then what has been described here, as it was independant of throttle position and only lasted for about a minute or so.

The dealer sez it was from the IAC, is a common complaint, and fixed it by adjusting the throttle stop to a faster idle. So far it hasn't come back, but it has been warmer outside in the mornings.

gerry

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2000 4x4 XLT SOHC V6

 

[felsmann]

Well, good point there. My problem started last June after the dealer replaced my IAC. However I never complainted about it and now it's out of warranty.

The only thing I noticed that may not be normal is this plastic cap on it. It's ablack cap that is pretty loose. Can you check on your and see if it's loose on it too?

Thanks!

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Juan Felsmann
'97 Sport 4WD 5spd
Warrior Twist
www.explorer4x4.com/thaven_juan.jpg

 

[felsmann]

PROBLEM SOLVED!!!

God, I'm glad I was able to figure this one out!! You guys experiencing the same thing as myself and sunbum have to do this:

Get yourself a can of AC Delco Throtle body (or carburator cleaner) aerosol and take the boot off your throtle body, turn on your car and empty the whole can!! (just follow the instructions on the can)

keep in mind that you need to put the boot on and off since your MAS will need to read some airflow or your car will stall. (Although in my case, as I was was spraying into the throtle body with the boot off, it would not stall, but I would put the boot back on right away after spraying)

I so GLAD!!

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Juan Felsmann
'97 Sport 4WD 5spd
Warrior Twist
www.explorer4x4.com/thaven_juan.jpg

 

[Ray Lobato]

Hey Juan,
So what you are saying is that your throttle body was dirty, and the cleaner cleaned it to the point that it does not make this sound anymore?

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Happy Wheelin'
Ray L.
97 XLT 4X4 4.0L SOHC
Dead Link Removed

 

[felsmann]

Ray,

Yes! you are right. I kind of got carried away on my post. ha ha Imagine how excited I'll be when I get my lift on!!



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Juan Felsmann
'97 Sport 4WD 5spd
Warrior Twist
www.explorer4x4.com/thaven_juan.jpg

 

[felsmann]

Well, guess what. I was wrong! I don't know I could not tell last night, but it is still there.

I guess it wont go away until I get a new throtle body.

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Juan Felsmann
'97 Sport 4WD 5spd
Warrior Twist
www.explorer4x4.com/thaven_juan.jpg

 

[pistol_fish]

I'm begging some one to discover what's causing the whistle. It only happens between 2000-2500 rpm at any speed and only under load. (as previously stated) and the tone of the whistle raises as you increase throtle and lowers as you back off. If you are in park and rev it up, you don't hear it at all. I've counted at least 10 posts on this board (I'm sure there's more) that report this problem. I have the KKM induction but the whistle was audible BEFORE I installed my KKM. I was hoping the KKM would be a possible fix. No such luck.

 

[Warren]

Three possibilites;

Dirty IAC (idle air control solenoid), remove and clean passages with Gumout spray cleaner.

The PCV valve could be gummed up and hanging at just the right opening value to cause a whistle, clean with Gumout spray cleaner.

Possibility of ..........get this! Crankcase Vent Harmonics, try placing a small restrictor in the crankcase vent line. Example, the vent line should be 1/2" diameter, so try placing a short section (1" long) of 3/8" hose inside current vent line. If the pitch or rpm level changes, this is the area to address.

Warren
http://www.kustomz.com
info@kustomz.com

 

[Hoppy]

Ok Guys, I see that the last post on this was about a year or two ago. I also see that there were numerous replies that asked "So, what is the problem"? I have bought a 1997 explorer 4.0 OHV back in December and since day one of owning it it has done this. It is ALL stock and I have pulled the throttle body off and cleaned the 1/8" of carbon build up on it and to no avail. It still whistles under load around 2000 to 2500 rpm, increasing its pitch as the throttle gets aplied. So, my question is this, once again. What is causing this problem?

Hoppy