Mechanics

"WHISTLING/REV" NOISE WHEN GAS

1995 Ford Explorer

Noises problem
1995 Ford Explorer V8 Four Wheel Drive Automatic 280000 miles

Alright, here's the low down: Anytime I accelerate past 35 mph as soon as I let *off* the gas (to either stop or slow down) a noise from the car engine area begins to make a " revving or whistling" type of high pitch noise. It immediately stops if I come to a complete stop or if I provide even the slightest amount of gas. I can also manipulate the noise (making it stop) if while braking I keep just a hint of pressure on the gas pedal. The RPM's slow down in time w/ the speedometer when the pressure is removed from the gas pedal. Also, the car does not in any way feel as if it is trying to " fight" my deceleration and the engine (as a whole) does not sound like it does when you begin accelerating. I have been unable to recreate the noise by sitting in neutral and revving the engine to simulate the same strain the engine may experience when going above 35 mph. It seems the problem is isolated to only occurring when the car is actually in motion. Lastly, my RPM's are all as they should and the engine is not sounding or acting as if the transmission is having any difficulties shifting to any speed. Any ideas would be extremely welcome. - Rob
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Sephiroth0574
April 25, 2010.




Could it be the fan clutch? Does it sound like a fan noise?

I'm not car repair inclined myself so I can only pass suggestions/idea along to my friend who is working on it. I can, however, attempt to give you a better description of the noise.

It reminds me of the sound that is made from a childhood whistle from the dollar store. The 1-2 inch long plastic tube you would place in your mouth and the harder you blew the higher the pitch would be and if let alone it would "wind down" in speed & pitch rather than abruptly stopping like a traditional whistle.


http://www.2carpros.com/forum/automotive_pictures/520918_2813whis6x15_1.jpg



The green one in the middle is the one I'm thinking of.
Hope that helps.

Tiny
Sephiroth0574
Apr 26, 2010.
Have your helper check for vacuum leaks too.

Let me know what you find.
Joe
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Will do Though it will be about this time next week before I can get back to you with results (I won't get my truck back to his place until Sunday).

There was a new symptom I just experienced about a half hour before I wrote this to you.

I was backing out of the driveway (idle speed) and the sound kicked in while in reverse, all " power" (reversing momentum) stopped (giving it gas did NOT stop the noise or allow the truck to move more) and as soon as I placed it in neutral it stopped.

I figured since this was a new piece of the puzzle it was worth tossing your way. Thanks Rob

Tiny
Sephiroth0574
Apr 26, 2010.
THis is a tough one. To me that sounds like a throtle position sensor (TPS). However, that wouldn't cause the noise. Let me know what you find. I'll be waiting.

Joe

Joe,

While we're waiting for the weekend to come and go so I can tell you if any of your suggestions panned out re: my Ford Exploder, I bought a 2nd vehicle on Wednesday. '93 GMC 1500 Pickup. 173,000 approx.
I used to work @ AT& T and the majority of their fleet was GMC trucks. I have noticed an identical problem (that I had while @ ATT w/ their trucks) with my " new" one.
As you are driving (or parked) the odometer will wildly kick from 0-max multiple times and @ the same time all the lights on the dash go nuts.

There appears to be no rhyme or reason to the " glitch".
Lastly, when the battery light flashes in the cluster of flashing lights the engine begins to sound like it wants to stall yet once the battery light blinks out again the engine resumes its steady hum.

Dashboard cluster maybe?

Thanks, Rob

Tiny
Sephiroth0574
Apr 30, 2010.
They did have problems with the cluster. Before replacing it, however, have the body control module tested. When they go bad, things can get crazy.

Joe,

Well, the weekend was semi-productive. The loud " growling" noise from my bad hubs is gone (replaced left & right), but the problem I mentioned to you is not. However, my buddy was able to check all the ideas you suggested and while they didn't pan out he did think of a possibility that he is 99% certain it is (based on on-line forums describing exactly the same symptoms) - The transfer case. The additional research he did uncovered that the pin that goes into the chain that helps control the 2x4 to 4x4 feature my explorer has can wear an oblong hole in the chain when fluid levels are not maintained (guilty) or just over time. At that point there is slack in the chain anytime I let off the gas, etc and the " whistling noise" is all the links in the chain dragging on the inside of the case. We're planning on taking it out Thursday/Friday and looking @ salvage yards (I do have 280,000 miles approx, so buying new doesn't seem feasible) to find a matching replacement. Any additional tips regarding trouble we could encounter in our project would be welcome or if you think that we might be chasing shadows I'd like to hear from you. Thanks Rob

Tiny
Sephiroth0574
May 4, 2010.
It very well could be the problem. Especially with that many miles. I just wanted everything checked before you start replacing parts. As far as the transfercase, make sure to get a direct replacement part (same year make and model).

Let me know how it goes.


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