EDIT: FIXED. Was a slipped clamp on a boot. Read below for more detail.

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I've had a strange sound for the past few months.

When I get on the accelerator beyond about let's say 40% of its travel, I hear a whistling sound that sounds like it's coming from the middle of the dashboard. It happens only when I'm in gear and moving down the road. It does NOT occur when I'm stationary and rev the truck. It comes and goes in concert with the position of the throttle pedal. When I keep the pedal stationary, it doesn't change, but if I press down it gets louder, and if I let off it goes away. It mostly comes on at about 2000 RPM, but sometimes comes in a little lower or higher than that.

The video linked below shows the problem. It really sounds like it's coming from inside the truck. You can hear that the engine noise sounds much farther away than the whistling sound.

Any ideas on how to fix this? I'm slowly going insane.

Thank you. Specifics on the truck are below in my signature. This happens in all DP Tuner settings, for what it's worth.

Strange whistling sound from Excursion - YouTube

 

Wow, never heard anything like that before. Almost sounds like electrical noise. Hopefully someone will come along with experience with this. Only thought I would have is either a leaking boot, although I would think it would get worse at higher RPM or Boost. Another thought is condition of the compressor wheel if it is touching the housing, have you removed the intake to check the wheel?

 

Make sure that all of your clamps on the charge air tubes are tight and none of the rubber boots have any holes in them.

 

Sounds like electrical noise to me too. I will try the under the hood suggestions you guys have made, but I personally think it may be the electronic door ajar chime that's somehow being activated continuously. And I may be nuts to think that.

Does anyone know where the chime itself is? I have been under the dash but haven't been able to locate it.

 

Is it really that loud, sound like air, at a high rate, check spider boots at intake, or compressor wheel howling, that's wild, please lets us know what you find.

 

One of the most puzzling things is that it does not make the sound when I'm in park and rev the truck. Which also makes it harder to isolate the sound. I'll try your suggestions too.

 

If it was electrical I wouldn't think it wold change pitch like it does as your RPMs increase. I would have to agree wit the others... Check all of yourIC tubes-n-boots. Also the spider itself to make sure nothing is loose. THe turbo does sit about center dash just on the other side of the firewall.

Did this start right after you put in the tuner or eventually start later afterwards? I am thinking with the tuner, increased boost pressure...something came loose.

 

I've had the tuner in for three years or so. Nothing else has changed under the hood since then.

I will check all that. What is / where is the spider?

Have also ordered the Dieselsite boot replacement kit, though I don't see any obvious loose clamps or cuts in the boots. Should be able to swap that in over the weekend. http://www.dieselsite.com/19995-2003...fter12198.aspx

 

THe spider is where the turbo splits into diff directions for the IC and the inbound exhaust. (Best explanation I have...sorry).

In the kit you posted though...THere should be more than 4 boots. I think there are 6 to include the boots for the IC tubes then the two for the turbo....
I am sure someone will chime in to smack me if I am speaking wrong.

 

Exactly right. I found that a clamp had slipped off the lower boot on the passenger side. Went ahead and replaced all the boots with the Dieselsite boots, and the problem is now solved.

Amazing that the whistle sounded so loudly in the passenger compartment. I guess it's a little like a teapot whistling when there's a leak in the charge air system.