Mechanics

CHEVY RESONANCE/WHINE NOISE

2000 Chevrolet Camaro

Noises problem
2000 Chevy Camaro 6 cyl Two Wheel Drive Automatic 64000 miles

There is a Resonance/whine noise that just started and it is most noticeable from in the car, it is not coming from engine compartment. It sounds like it is in the car under dash, under the floor shift console or from the middle to rear of the car.

The Car runs great, no stumble, no hesitation, starts all the time.

It happens a few minutes after I start it up and will sometimes will get louder/lower or go away for a few moments. Hot or cold makes no difference. When the car is in gear and I accelerate it goes away, when I come off the gas at a stop light or at idle in gear it is there. When I place the car in neutral and rev the motor it does NOT go away.

I thought it was the fuel pump but when I rev the motor at idle it is still there. It seems only when in gear under acceleration is when it goes away.

Is there something on the transmission, vacuum leak?
Fuel pump; but only disappears under acceleration?

Apparently, I did not remember asking questions before but I did so I will make a donation. Sorry

Peter
Avatar
Baran220
November 5, 2009.



Hello and thanks for the donation!

The best place to start with this issue would be inspecting your transmission and gearbox fluids. If they look or smell burnt, replace it. If they are OK, it maybe a failling torque converter. Whining noise in this area is very hard to diagnose without simply raising the vehicle and inspecting every component in that area in person so you can listen for the sound.

I want to thank you but it is not a transmission problem.

I service and check fluids constantly, fact is I am anal where it comes to this.

The best I can guess is the Fuel pump but what bothers me is that when I put the car in park of neutral and rev the motor the sound is still there. Only when in gear and under acceleration, even slight acceleration it stops. Otherwise the car runs like a champ, no bad shifts, no hesitation, no nothing other than this insane noise!

I live in Rochester, NY and the car has never seen snow or salt BUT since the weather has been good I took the car out the other day.

The noise was gone. But I know it will rear its head again.

No, I do not smoke anything just in case you are wondering. The noise is real others have heard it but have no clue.

Updated 11-9-09

I have one that may stump the best but I hope not!

I have a 2000 3.8 V6 Auto with 64,000 miles. Car runs great, great condition, no problem at all with anything EXCEPT: I just starting hearing a resonance noise/hum but only in the passenger compartment, it is not coming from under the hood. It happens a few minutes after I start the motor and whether the motor is hot or cold does not matter. I have run 150 miles @ 75 mph or 10 miles, same sound, same symptoms.

The resonance noise/hum stops but ONLY when I am in gear and under acceleration, even slight acceleration but comes back when I slow down and sit at idle at a light. Once I hit the gas it goes away. Sometimes it is a low hum and other times it is very noticeable.

NOW, If I put the car in neutral and rev the motor the sound does NOT go away BUT once I put it in gear and accelerate its gone until I slow down again.

Fuel Pump?
Vacuum Leak on the tranny under the floor shift console?
Sending Unit in the tank?

It is not exhaust?

I cannot tell where this is coming from?

The only thing that has been a problem is the sending unit in the gas tank it does not give me an exact reading of fuel at the gauge.

Please give me some clues?

Tiny
Baran220
Nov 10, 2009.
Okay, so the engine must have load on it to cause the noise. Does it do it if you put the vehicle in gear but stay at idle without accelerating?

Bluelightnin6
Nov 10, 2009.
" bluelightnin6" wrote: " Okay, so the engine must have load on it to cause the noise. Does it do it if you put the vehicle in gear but stay at idle without accelerating?&Quot; Actually " bluelightnin6" it is just the opposite of what you wrote above.

The noise goes away under load, even under slight acceleration the noise gets faint or goes away. The noise is only present at Idle whether in drive, or in neutral, (this is an automatic).

The strange part is this; if I am in Park or neutral and rev the engine the noise is still present. It is only when I am in gear and under acceleration is when it disappears. Since, if when I am in Park or neutral and rev the engine and the noise is still present, in my opinion it should eliminate a fuel pump problem unless the fuel pump reacts/vibrates differently when in gear and under acceleration?

This noise is an actual high pitched " hum", not metal/mechanical. It is as if there is some sort small electric motor or PUMP running and humming until I hit the gas in Drive.

Believe me, I know this is strange. I have had vehicles in the past that produced a " Resonance" noise at certain times but it was usually caused by a drive shaft or tire when running at speed.

Tiny
Baran220
Nov 11, 2009.
Haha, I understand. Sorry for the late response. I was just getting some input from some other techs on here. Here is what one is thinking that really seemed like a good possibilty.

" What you thing about trany oil pump whine when engine running park, neutral oil pump turns. When accelerating pump speed increases and possible whine stops. Ie. Road noise etc. &Quot; Can you listen closely to the pump to see if this is on target? Or you are positive now that it is coming more from the fuel pump / tank area than the tranny area?

Bluelightnin6
Nov 11, 2009.
[quote=" bluelightnin6" ]

" What you thing about trany oil pump whine when engine running park, neutral oil pump turns. When accelerating pump speed increases and possible whine stops. Ie. Road noise etc. &Quot; Blue,
This is something to truly investigate but wouldn't you think that the tranny pump would be a more noticeable and distinctive sound and give up its location? I have noticed that the shifts are a bit more harsh but I attributed that to the 60K Fluid Flush that is due. I checked the fluid and it is not burnt or low.

" Or you are positive now that it is coming more from the fuel pump / tank area than the tranny area?&Quot; It is one of those noises that you think you hear over there, then over there, then over here. I feel like a dog chasing my tail.

BUT, I will take your advice on the tranny.

I have locked down this hum from three place. 1) Under dash, 2) Under floor shift console, which could be the tranny and 3) From the rear of car which could be the fuel pump.

Question: Would a bad fuel sending unit in the tank make a hum like this? I have had problems with the sending unit sending wrong readings to the fuel gauge.

Tiny
Baran220
Nov 11, 2009.
Sorry all,

Been busy so I did not post what was found.

The resonance noise was a heat shield around the catalytic converter, specifically the upper heat shield.

I was on a 400 mile trip when a rattle got so bad from under the car I went into a local repair shop 300 miles from home. What they thought was a catalytic converter lower heat shield vibrating turned out to be the upper heat shield.

This was discovered after they ripped the lower heat shield off.

The fix was to " metal" strap the upper heat shield to the converter because the upper shield is necessary to prevent the catalytic converter heat from coming into the the floor boards.

This stopped the resonance noise.

Strange things, resonance noises. Heat from the catalytic converter?

Now I will have to spend $400.00 to change the catalytic converter even though it is still good.

Does anyone know if a " new heat shield" can be done independently?

Tiny
Baran220
Dec 29, 2009.
The cat. Converter does not have to be replaced if it was just a loose heat shield vibrating. The shield can be mounted back properly and the same converter can be used.

Thank you, bluelightnin6

Unfortunately the lower part of the heat shield was destroyed, the upper is still there. They used a wheel cutter to break the welds.

Is there a way/method to find/install a replacement shield either new or used from a junk yard?

Tiny
Baran220
Jan 5, 2010.
Any exhaust shop should be able to replace the heat shield for you, they may have to cut some hangers to let the exhaust drop down but they can definitly replace it. Finding a replacement for a 2000 camaro is probably going to be fairly easy too since a lot of young kids drive them and wreck them alot. Your local salvage yards should be able to help find it for you.

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