Hi Pitched Electronic Noise...

AWD Chaser · 03-04-2006, 07:23 AM

I posted aboot this a while ago, but now it's a bit more frequent and really starting to annoy me.

Intermitently when driving along, I get this high pitched frequency noise, so high pitched you can just hear it but it's really loud.... almost like your ears are ringing.

Anyways, the problem is it only happens when driving, and never lasts longer then 10 seconds before it goes away so I can never trace the source of the noise. It happens with or without the aircon on/off, radio on/off, cruise on/off. Can anyone please help!!!!

It sounds like it comes from somewhere around the dash. I doubt this noise would be coming from the engine bay... not loud enough.

tex · 03-04-2006, 08:26 AM

Maybe a crook electrical relay, they sometimes do this when buggered.

Racecraft · 03-04-2006, 09:02 AM

some have a siren fitted to the low water alarm... Clean the sensor in the header tank if you have one fitted

AWD Chaser · 03-04-2006, 09:08 AM

Nah. No low water sensor for me. AU3 Futura.

I know that capacitors and relays and stuff can cause this high pitched squealing, but which one and where. The bigger problem is, is that this is an ex police car, so there is extra wiring and relays everywhere they I may not know of etc...

Any ideas?

Racecraft · 03-04-2006, 09:11 AM

It might still have the siren though even without the sensor in the tank.. IIRC alot of the police packs had them fitted.. I'd have to do some ringing around to find out how to disable it though, or where it the trigger is for that matter

XR6-VCT-2000 · 03-04-2006, 03:24 PM

i doubt weather this is ya problem , allthough what you described sounded like my problem right to the tee !...
My old ford laser used to do this - and from my experience with buggered capacitors i thought that was the problem (sounded electrical high pitched to me and most others who heard it too ! ) , i searched hi and low , had the complete dash out checking all electrical parts ( as it sounded like it was coming from behind the dash ).....
lol .. in the end - never was able to fix it , put it all back together etc etc then i met another bloke a few months later who suggested maybe it was the front wheel bearings running a bit dry on grease... i pulled them out / got them repacked with grease / and sure enough that was the problem ... i couldn't believe it , like as you had decribed above, with like my car too - if you was sitting in the car it sounded really electrical high pitched (only happened when driving it) - like a buggered capacitor or something and only lasted for about the first 10 to 15 seconds of driving ..
lol - i don't wanna lead you down the wrong track ! - so make sure you check everything else first, but if you never find the problem it might be worth looking into ??
...yeh i know they are a sealed ball bearings unit and shouldn't need to be repacked with grease before they finish their lifespan and all but it still happens apparentlly , not everyhting comes out of the factory perfect ! ..lol
good luck with it anyway ;) .

AWD Chaser · 03-04-2006, 05:07 PM

Well, if that is the case, how would I go about greasing them up woman! (scot accent) being a sealed unit and all. With my experiance of pulling out dashes, I would rather pull apart a wheel assembly then a whole dash, esp a newer car too...

svo347 · 03-04-2006, 05:22 PM

Are you married :P

XR6-VCT-2000 · 03-04-2006, 05:28 PM

As i said - check everything else out first , as i wouldn't want to have you do the above and find it's not the problem ! - it might be - it might not .
But as far as them being a sealed bearing unit and getting them repacked with grease, if you remove them and take them to a bearing place or a good mechanic with a hydraulic press , they can pop the centre out , check out how much grease was actually in them , clean them all out , check the bearings while at it (might need new complete new bearings unit!).. if the bearings are ok then just a repack with grease and they seal them back up again/press the centre in again. That was with the ford Laser front wheel sealed bearing units/ was a front wheel drive so they may vary a bit to the AU !!... but that being said i can't see it being much different , bearings are bearings regardless of front or rear wheel drive and a sealed bearing unit is a sealed bearing unit imo - so it should be possible to just repack the bearings with grease if thats all the problem is .
Again --> good luck with ya problem , i only originally left this as a post for a last resort if your going nuts with no luck finding the source of the hi-fequency noise.
I am not stating that this is your problem !!!! , just maybe - as it is possible for a tadd dry bearings to make that noise , very rare , but possible .. gl ;)

oh , just thinking too , the AU bearing units would probably be rather larger than a small ford lasers bearing units, so the beaings might have to be heated up first for them to be able to pop them open , being much thicker metal housing and inner around the bearings - thus burning out any of the original grease left anyway - wouldn't be good if you wanted to inspect how much grease was originally in them ..

AWD Chaser · 03-04-2006, 05:36 PM

Hmmm. I may just have to put up with it until the next service. Thing is, the bearing issue is a much easier place to start then the electronics, as my car is more complicated then a standard (exeption of high series).

Quote:

Are you married

Almost.... I just want to buy my plasma first... lol

XR6-VCT-2000 · 03-04-2006, 05:40 PM

Quote:

Originally Posted by au3 chaser

Almost.... I just want to buy my plasma first... lol

ahahahah ..lmao , now your a bloke who's got his prioritys right ! ..lol

: the plasma is a must first ! ..lol

GK · 03-04-2006, 07:19 PM

Why would you bother taking the bearing out, taking it to a joint to open it up, then to regrease and refit?

Just try everything else first, and if the problem persists, just replace the bearing closest to the noise! Front right, right!

GK

TwistedEL · 03-04-2006, 09:29 PM

Most of the capacitors will be in:
BEM
ECU
If you don't have climate control it won't be there.
Maybe the trip computer if one's fitted.

If you can hear coming form the dash while driving I'd say it's not the ECU
So the smart money is on the BEM...

It could also be a very small vacuum leak, that would squeal.

Just some simple suggestions before mucking with the bearings.

AWD Chaser · 03-04-2006, 11:07 PM

It's not so much of a squealing noise as it is a high pitched frequency noise... almost like when you can tell a computer monitor or TV is turned on...

richo77 · 04-04-2006, 02:53 PM

I know exactly what this is. I had the exact same problem with my AU, Ford warranty covered it after blaming my alarm of all things. It turned out that they have it in their 'common problems with AU' bulletins they get.

The high pitched noise came when at about 3,000 revs and didnt stop till the revs were right down to idle. Problem drove me nuts, was thinking of getting rid of it at one stage because of it.

It is called an 'actuator' on my service invoice.. it is the mechanism that changes the direction of air flow. At the moment it will be stuck in between air flow directions meaning as air is forced through a small gap it makes that annoying noise. You need to pull apart the dash (a huge job apparently) in order to replace the part.

Sorry if i havent explained it properly.

Cheers
Nathan

AWD Chaser · 04-04-2006, 09:53 PM

I might just see some obvious things when it happens again (RPM, heater temp) and see what happens if I floor it.

richo77 · 05-04-2006, 03:13 PM

I was able to track it down by switching from 'Recirc air' to 'fresh air'

XR6-VCT-2000 · 06-04-2006, 01:49 AM

yeah the AU's "so called" fresh air does stink a bit..
As far as the high pitch noise you are hearing , maybe yo are going deaf ! , ringing ears is the first sign of deafness ! ..lmao ..jokin ! ;) next you'll be forgeting to turn your indircator off ! ( like some other deaf dude in these forums complaining about he can't hear his indicators .lmao ) ..
joke joke joke !!! ..lol

AWD Chaser · 06-04-2006, 03:52 AM

If i'm deaf, does that give me an excuse to lean on the horn? lol.

:

allan · 07-04-2006, 03:08 PM

I had a similar problem in an old commodore and then noticed it in my mates EL Fairmont. I'm positive that it is a vacuum leak or restriction in the the vacuum lines for the ventilation system. It only occured at a certain speed in the commodore and no matter what you did it was there. Bloody holdens. In the EL we played with the recirc/no recirc switch and it dissapeared. Try some changes with the vent system next time and maybe it will dissapear like the EL