help diagnose whining noise

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skep419

skep419

5.9 Magnum 4 speed afficionado
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[ame="https://youtu.be/rRs82czLQjE"]https://youtu.be/rRs82czLQjE[/ame]

noise changes with throttle.
 
Can barely hear it in the video, but it sounds like an electrical noise.
Like a coil or spark noise of some kind.

Was the radio on, or on and turned down?
Where is your coil mounted?
Inside by chance?
 
TrailBeast said:
Can barely hear it in the video, but it sounds like an electrical noise.
Like a coil or spark noise of some kind.

Was the radio on, or on and turned down?
Where is your coil mounted?
Inside by chance?
Click to expand...

no change with radio unhooked

on the intake
 
denso alternator
attachment.php
 
It sounds late,, what's the timing..??

I don't hear a whine as much as a "whistle" maybe vacuum leak..

but it's late...

Does it have the air filter on, If not ,, see what it sounds like the the A/Filter on..

cheers
 
I hear more of a whistle. Some of the other noises are more normal. I'll think about it.
 
It is kind of a whistle noise. No vacuum leak. Air filter is on. Sound is coming from inside the car. I'm leaning towards some kind of electrical/alternator issue. It sounds like a stereo ground loop that changes with load.
 
I would say spray a little water on the belt, but if you are sure it is inside, probably some sort of radio interference. Instead of just turning off the radio, can you disconnect the speaker?
 
magnumdart said:
I would say spray a little water on the belt, but if you are sure it is inside, probably some sort of radio interference. Instead of just turning off the radio, can you disconnect the speaker?
Click to expand...

That's what I would try, because even though the radio may not be on or playing the amp can still transfer noise.
 
unhooked the power to the radio. also i only have rear speakers and the noise is coming from the dash area.
 
skep419 said:
unhooked the power to the radio. also i only have rear speakers and the noise is coming from the dash area.
Click to expand...

In this case I would use a short section of hose and start stethescoping for the noise.
 
What other electronics are installed? CB, GPS, power booster, EQ, FM converter, 10,000 watt sub woofer amp, automatic electric antenna, dedicated memory hot wire. Is the noise left, right or center to the dash? Have you tried disconnecting the alternator? Does the radio play ok? That just sounds like a pulley squeak. If it didn't change with engine speed I would wild guess blower motor noise.

Did you try the water trick?
 
Your OEM alt gauge is showing negative, did you leave a wire on it? maybe source of electrical, hot wire it see if it goes away. sounds like air though, vacuum controls on the heater/AC box? if it goes away at throttle dump and comes back its probably vac
 
TrailBeast said:
In this case I would use a short section of hose and start stethescoping for the noise.
Click to expand...

i can sure give this a try.

magnumdart said:
What other electronics are installed? CB, GPS, power booster, EQ, FM converter, 10,000 watt sub woofer amp, automatic electric antenna, dedicated memory hot wire. Is the noise left, right or center to the dash? Have you tried disconnecting the alternator? Does the radio play ok? That just sounds like a pulley squeak. If it didn't change with engine speed I would wild guess blower motor noise.

Did you try the water trick?
Click to expand...

Just a standard working Sony CD player with 2 6x9s. It's hard to tell exactly where it's coming from but it sounds like center of dash.

Breadburner said:
Window gasket leak.....
Click to expand...

Changes with throttle

grjammer said:
Your OEM alt gauge is showing negative, did you leave a wire on it? maybe source of electrical, hot wire it see if it goes away. sounds like air though, vacuum controls on the heater/AC box? if it goes away at throttle dump and comes back its probably vac
Click to expand...
I think I left it hooked up to power the fuel gauge. Aftermarket heater. No factory box.
 
doesn't do it cold. Only at operating temp.

I will try unhooking alternator
 
I'm kinda with inertia(post9), vacuum. I cannot ever recall a throttle position whistle-sound not being carb or intake related. But, boy, it's being inside is a real poser allrightey!
 
AJ/FormS said:
I'm kinda with inertia(post9), vacuum. I cannot ever recall a throttle position whistle-sound not being carb or intake related. But, boy, it's being inside is a real poser allrightey!
Click to expand...

It's possible since he said it only does it when warmed up.

Did we ever get an answer as to if gassing it makes it go away for a second till vacuum comes back up?
 
Remove the alternator belt and drive it a short distance.
 
Do you have a mechanic's stethoscope. The less expensive ones are very reasonable. I think I paid $8.00 at HF for mine. I had a similar noise once, and it wound up being the bearings in my alternator. One would expect a grumbling noise, but it was more of a high pitched squealing or whining. Anyway, with a stethoscope, you can touch things one at a time and very likely track down that noise.
 
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