5.4 Exp - whining/humming when decelerating
Thread Starter
|
Postmaster
Joined: May 2002
Posts: 3,028
Likes: 1
From: Annapolis, Maryland
5.4 Exp - whining/humming when decelerating
Hi all,
This is my first time posting on this forum, and you guys seem to know a lot. I have a 99 Expedition 5.4L that makes a kind of "airy" high pitched hum, but only when you let off the gas and the truck's in gear. It kind of sounds like those toys kids have, you know, the plastic tubes that whistle when you spin them around? but it only does it when I'm in Drive and and I let the gas off - I can't duplicate the sound sitting still.
Any ideas?
XXL
This is my first time posting on this forum, and you guys seem to know a lot. I have a 99 Expedition 5.4L that makes a kind of "airy" high pitched hum, but only when you let off the gas and the truck's in gear. It kind of sounds like those toys kids have, you know, the plastic tubes that whistle when you spin them around? but it only does it when I'm in Drive and and I let the gas off - I can't duplicate the sound sitting still.
Any ideas?
XXL
Thread Starter
|
Postmaster
Joined: May 2002
Posts: 3,028
Likes: 1
From: Annapolis, Maryland
5.4 Exp - whining/humming when decelerating
>I certainly don't know alot but my guess would be something
>in the driveline. Where is is coming from?
I thought about that, but it sounds like it's coming from under the hood - I found out today that if the truck's been sitting, when it hits fast idle in the morning and you put it in gear, it makes the noise for a second. I'm going to have my girlfriend sit in there, foot on the break, and put it into reverse while I pay attention. Hopefully I can isolate the noise.
My suspicion is that it has something to do with the intake - It did it before my K&N FIPK installation, but it seems to be louder now. I'll let you know of my findings...
Thanks for the reply
XXL
>in the driveline. Where is is coming from?
I thought about that, but it sounds like it's coming from under the hood - I found out today that if the truck's been sitting, when it hits fast idle in the morning and you put it in gear, it makes the noise for a second. I'm going to have my girlfriend sit in there, foot on the break, and put it into reverse while I pay attention. Hopefully I can isolate the noise.
My suspicion is that it has something to do with the intake - It did it before my K&N FIPK installation, but it seems to be louder now. I'll let you know of my findings...
Thanks for the reply
XXL
New User
Joined: Apr 2002
Posts: 7
Likes: 0
5.4 Exp - whining/humming when decelerating
OK, I am lost now. You said in gear. Does that mean you are moving or just putting it in gear? Let's hear the details of your test. By the way, make sure you are out of the way when your girlfriend has her foot on the brake while you are looking. My wife always has this evil grin when I ask her to do things that might kill me.
Thread Starter
|
Postmaster
Joined: May 2002
Posts: 3,028
Likes: 1
From: Annapolis, Maryland
5.4 Exp - whining/humming when decelerating
Test didn't work...
Anyhow, it only happens when there's a "load" on the engine (when it's in drive or reverse). Can't get it to hum when it's in park. I also have to rev the engine above 2500 - it's really apparent when I rev it up, but it doesn't shift, so it decelerates (engine braking) as soon as I let off the gas, it happens. It can be best described as a hum, but high pitched. I think it's some sort of intake or vacuum leak. I've put on a K&N FIPK and it seems to be louder now. I also replaced the PCV valve. Maybe I yanked a hose loose?
XXL
Anyhow, it only happens when there's a "load" on the engine (when it's in drive or reverse). Can't get it to hum when it's in park. I also have to rev the engine above 2500 - it's really apparent when I rev it up, but it doesn't shift, so it decelerates (engine braking) as soon as I let off the gas, it happens. It can be best described as a hum, but high pitched. I think it's some sort of intake or vacuum leak. I've put on a K&N FIPK and it seems to be louder now. I also replaced the PCV valve. Maybe I yanked a hose loose?
XXL
Post Fiend
Joined: Jan 2002
Posts: 5,859
Likes: 7
From: USA
5.4 Exp - whining/humming when decelerating
This could be caused by the thermostatic clutch fan,
the hub itself is fluid filled with heat or cold could be causing your noise.
also powersteering pump or altenators can cause noises
Try turning on all accessory's at idle
have you changed back to stock filter setup to see if it goes away?
just some thoughts!
Rich
Ford Trucks Built Tough!
not with rocks
Watch out "X" Mayor of Truckville
the hub itself is fluid filled with heat or cold could be causing your noise.
also powersteering pump or altenators can cause noises
Try turning on all accessory's at idle
have you changed back to stock filter setup to see if it goes away?
just some thoughts!
Rich
Ford Trucks Built Tough!
not with rocks
Watch out "X" Mayor of Truckville
Thread Starter
|
Postmaster
Joined: May 2002
Posts: 3,028
Likes: 1
From: Annapolis, Maryland
5.4 Exp - whining/humming when decelerating
I haven't tried putting the stock intake back on, because the sound was there before...
I think it may have something to do with a hose...can't shake the feeling....
I doubt it's the alternator/PS Pump, 'cause it's got a "breathy" air sound to it...it sounds like air is whistling back through the intake when I let off the gas, and it's whistling at me...
XXL
I think it may have something to do with a hose...can't shake the feeling....
I doubt it's the alternator/PS Pump, 'cause it's got a "breathy" air sound to it...it sounds like air is whistling back through the intake when I let off the gas, and it's whistling at me...
XXL
Trending Topics
Freshman User
Joined: Mar 2002
Posts: 41
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
