E 240 Interior Noise

[DaveG38]

Hi,
Can anybody help me to trace a strange noise in my E240 Auto? The car is a 1998/99 model with just under 40k miles on the clock. The noise is a very high pitched electonic whining whistle that starts the moment the key is put in the ignition and turned to the ignition 'on' position (but silent when the key first goes into the lock). It is clearly audible before start up, and is still there when the engine is running at idle. At higher speeds it is drowned out by road noise etc. It seems to me that this high pitched sound is electronic, and starts up when the dashbord electronics fire up. It is so high pitched that it is impossible to say exactly where in the car it is coming from.

Any clues anybody? Or am I missing something obvious?

Thanks in advance.

DaveG38

 

[television]

Hi,
Can anybody help me to trace a strange noise in my E240 Auto? The car is a 1998/99 model with just under 40k miles on the clock. The noise is a very high pitched electonic whining whistle that starts the moment the key is put in the ignition and turned to the ignition 'on' position (but silent when the key first goes into the lock). It is clearly audible before start up, and is still there when the engine is running at idle. At higher speeds it is drowned out by road noise etc. It seems to me that this high pitched sound is electronic, and starts up when the dashbord electronics fire up. It is so high pitched that it is impossible to say exactly where in the car it is coming from.

Any clues anybody? Or am I missing something obvious?

Thanks in advance.

DaveG38

It could be the injector pump or ABS pump, they all make varying high pich singing noise around 7-8khz

Malcolm

 

[G MAN]

Was it you Malcolm that referred to cars all too often going in for one problem to be fixed & coming out with a new one? An familiar episode for lots of us.
I recently had ,so far , my rogh running problem sorted as posted previously & now have these identical symptoms as DaveG38 above.
The source seems to be under the inlet manifold and may well be the ABS pump ( brake boost pump according to Russian site) a very loud hi pitched urgent tone that fluctuates with use of the brake pedal, but now so intrusive can be heard inside the car when driving.
Don't know the exact cause or solution but wasn't there before things were removed & replaced but may have previously come on with the ignition & then diminished, though now sounds like it' s very upset. Will have to let it persist for now & braking seems unaffected but worrying none the less.
Will try & hit it with a hammer & report outcome.......
Any ideas out there??
s202 Kompressor BTW

 

[television]

Was it you Malcolm that referred to cars all too often going in for one problem to be fixed & coming out with a new one? An familiar episode for lots of us.
I recently had ,so far , my rogh running problem sorted as posted previously & now have these identical symptoms as DaveG38 above.
The source seems to be under the inlet manifold and may well be the ABS pump ( brake boost pump according to Russian site) a very loud hi pitched urgent tone that fluctuates with use of the brake pedal, but now so intrusive can be heard inside the car when driving.
Don't know the exact cause or solution but wasn't there before things were removed & replaced but may have previously come on with the ignition & then diminished, though now sounds like it' s very upset. Will have to let it persist for now & braking seems unaffected but worrying none the less.
Will try & hit it with a hammer & report outcome.......
Any ideas out there??
s202 Kompressor BTW

You could check that all of the vacuam pipes are ok, the ABS pump does not start working until the engine is running. Maybe someone else will know more.

Malcolm

 

[jberks]

Clearly it's hard to say. Odd that you can hear it from the inside of the car as engine bay noise is well damped and I could hear nothing from the engine bay with the doors shut.
I did have an identical whine on my E240 which was the throttle actuator. Gently blipping the throttle whilst the engine is off (ignition on) made the noise waver. Nothing wrong though.

The only other thing I had whine was the fan regulator - it's more of a whistle and comes through the air vents and from above the passenger footwell.

The 3rd thing that comes to mind is the ambient temperature fan - but I believe this is housed in the roof console so i'd imagine you'd have traced that one.

 

[G MAN]

Thanks boys, it's definitely the ABS pump & it's very noisy & vibrating too. Will follow all good practice & resist hitting with a hammer & return to indie to resolve.Definitely not there before the manifold was taken off to replace pipes & valves so i guess somethings not back where it should be . Because the noiseit is affected by the brake pedal I wonder if it related to the switch that causes so many tales of woe ? (The throttle body does hum but a much softer & lower note! )

 

[DaveG38]

E240 Interior Noise

All,
Many thanks to all of you for the varying advice. However, I have now identified the problem - so simple, yet difficult to find. Turns out that the noise disappears immediately on pressing the 'open' button on the Sony radio. As soon as the cover starts to open and disconnects the front, the noise disappears!! So the fault is probably an almost molecular level poor connection on the front cover, which is vibrating when powered and produces this very high frequency whine. Interesting!! Answer is probably to replace the front or the whole stereo system.

DaveG38

 

[jberks]

All,
Many thanks to all of you for the varying advice. However, I have now identified the problem - so simple, yet difficult to find. Turns out that the noise disappears immediately on pressing the 'open' button on the Sony radio. As soon as the cover starts to open and disconnects the front, the noise disappears!! So the fault is probably an almost molecular level poor connection on the front cover, which is vibrating when powered and produces this very high frequency whine. Interesting!! Answer is probably to replace the front or the whole stereo system.

DaveG38

Novel - didn't think of that one, though I didn't know you had a sony!
Actually my Dad's Sony in his W202 does exactly the same thing!