GTE Electrical Whine

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2837GT
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Joined: Wed Aug 06, 2014 7:55 am

GTE Electrical Whine

Post by 2837GT »

My GTE has started making a strange electrical whine audible in the cabin.
It happens when the key is turned to the on position before I press it in to start the car.
The car starts as normal.
The noise continues.
It seems to come from behind the dash, but it is hard to be sure.
I will have a proper look later, I think it will be a good idea to start removing fuses and see if the removal of any of them stop the noise.
Any thoughts on this and possible causes would be welcome !
Thanks in advance...

Update: I have removed the top fuse on the LH panel. The noise stops. So it is something to do with the starting system.
The noise is coming from the engine bay, not from behind the dashboard as it first appeared.
Any ideas welcomed...
2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Update on update.
More oh a screech than a whine now, perplexing !
Note all interior fans are off, and this is (almost) definitely coming from the engine bay.
As I said above if I take out the top fuse in the LH bank (coils/starters) it stops.
I also tried disconnecting each coil, no difference.
Maybe something in the starter motor?
John Vardanian
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Re: GTE Electrical Whine

Post by John Vardanian »

I would install a sort of a dB meter ap on my phone and chase it that way.

john
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2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Good plan John, will give it a go later.
2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Hi John, I did as you suggested the noise is loudest (99 dB) in the engine bay by the coils. Marginally louder by the drivers side coil (LHD car). Taking the leads out of the coils makes no difference. Can you think of a likely suspect in that area?
Thanks, Graham
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tyang
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Re: GTE Electrical Whine

Post by tyang »

Hi Graham,

This is a new one to me. The top left fuse should only operate the coils, so if the noise goes away when the fuse is removed, you can further isolate the circuit by looking at the wires that are fused on one side of the fuse junction. You said the noise does not go away when you take the wires out of the coil, so that means something else must be on the circuit. Look at the fuse junction in question and determine which side is being fused. There should be more wires on one side of the fused circuit than the other. This should be the side with wires heading to the coils. You can disconnect them with a flat bladed screw driver one by one, and eventually the noise should stop. Trace that wire, and it should lead you to the source.

Let me know what you find.

Tom
'63 330 America #5053
2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Thanks Tom, will do so and will report.
John Vardanian
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Re: GTE Electrical Whine

Post by John Vardanian »

Graham, I gather from your descriptions that first, the sounds is a screeching type, (like coming from a dry motor bearing) and secondly, it is the loudest near the coils, which is also where your heater box is (correct?). How sure are you that the fan motor is not the culprit? Have you actually killed the feed to the fan motor(s)? In my car the fan motor is on rheostats switch, and if the r/s blade is not properly parked the motor will continue spinning, even if the switch is off.

john
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chris
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Re: GTE Electrical Whine

Post by chris »

Hello John,

I agree that this would be also my first thought but for the connection to the upper left fuse. Graham says it stops as soon as he removes this. Assuming the wires are still according to the wiring diagram this fuse is connected to the coils and the alternator/ generator regulator based on the excellent wiring diagram for the S3 I have from Kerry. Therefor I would check for the coils as already suggested as well as for the underdash regulator by disconnecting them. What I do not know is how much the wiring between a S3 and a S1 differs.

Christopher
2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Gentlemen, thank you for your assistance.

John the noise is hard to describe but is not like a bearing in a fan.
The noise occurs when the fans are off and their respective fuses removed.

The noise persists with the key in position 2 but the engine not running.
The sound is more electrical than mechanical.
I have disconnected the positives from both coils, no joy.

There are three wires that run into the right hand side of the top left hand fuse.
Following Tom's advice I removed one, and the noise stops.

This wire runs from the fuse holder along the bulkhead and disappears behind the metal cover bolted onto the bulkhead.
On the front of this cover is the bonnet catch.
I have run out of time to investigate further today but do we know what lies behind this cover
chris
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Re: GTE Electrical Whine

Post by chris »

Graham,

directly behind the bonnet catch is the blower motor for the interior. Are you sure that it is not that? Use a stetoscope or long screwdriver to touch it and listen if sound comes from it.

Again, from my S3 wiring diagram from Kerry I assume 3 wires on the fuse you mention. Two to the coils, one to the regulator. Have you tried to disconnect the regulator? I described on fchat in your thread were you wil find it.

Christopher
2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Hi Chris, that will be my next task.
I am sorry for the slow progress but I have very little knowledge of auto electrics.
I have turned the blower motor on and off, it sounds absolutely normal.
Further when I remove the fuse that would disable the blower motor the whine continues.
I will repeat the process tomorrow to be sure.
Also i am sorry about posting across the two Ferrari forums, to be honest I much prefer this one, though uploading pictures here is frustrating.
I will look at the regulator, and check your F’chat post again. As i understand it the regulator functions to control the voltage produced by the alternator (my car has an alternator rather than a dynamo). The noise comes on when the key is turned so the alternator is not generating voltage.
Where is the regulator located ?
What does it look like.
Is it capable of making a noise?
Can it be replaced easily ?
I am on the verge of handing this over to a professional classic car electrician, but even if I can’t fix it myself, the more I know, the less it is likely to cost me !
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tyang
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Re: GTE Electrical Whine

Post by tyang »

Hi Graham,

The voltage regulator on an early car might be mounted on the fuse panel down towards the bottom of the panel. The early ones are about 3inches by 2 inches and have a steel cover that might be black. The later cars have a red plastic voltage regulator mounted inside the car behind the glove box. It's sometimes under the carpet. look up under the dash in the passenger foot well. From your serial number, I think it should have the regulator mounted in the engine compartment on the fuse panel.

The VR could possibly make this noise.

Tom
'63 330 America #5053
Jimmyr
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Re: GTE Electrical Whine

Post by Jimmyr »

Some additional input on Tom's note; the red voltage regulator (Marelli) is a solid state type and cannot make any sound (ditto for the Lucas). The black voltage regulator with the metal cover is a relay type and can make a buzzing sound even when the engine is not running. Put your hand on it as you may be able to feel the buzzing easier to locate the source.
2837GT
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Re: GTE Electrical Whine

Post by 2837GT »

Ok , this is interesting. I decided to check functionality with the mystery wire disconnected.
The objectionable noise ceases,
None of the electrics operated from the central console cease to be operational.
The starter motor woks and the engine turns over.
However the battery needs a charge. The car has been started a good few times during this investigation without a drive.
I will charge it tonight.
Tomorrow I will try to start the car with the wire disconnected.
IF the car starts, what can the wire be for?
IF it doesn’t I will start the car with the wire connected and the noise blaring,
So, if it only starts with the wire in place I suspect it is something to do with the coils.
If the car starts without it, and everything works without it, I am inclined to tape it off and ignore it, at least until the car can be given to an experienced autoelectrician

Does that sound logical ??
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