Technical Fuel Computer Buzzing.

[Daytona600]

Hi,
Can you help me, I've been working on my fiat stilo 2.4, and I removed the battery tray and the all the wiring to change the bulb? And I put it all back as I found it, but now the fual computer is making a buzzing noise? It is located top right corner above the air in take it has 2 connecters on the top? Could this be because I have low fuel??
Cheers

 

[Shadeyman]

Could you take a photo of the Fuel Computer so we know exactly what part it is your talking about.

Is it item 6 in the diagram below?

Could it be the thottle body(item 1) thats buzzing?

If it is maybe you need to do the throttle re-learn proceedure?

 

[Yellow Peril]

I think he means the main ECU that sits on top of the throttle body - shown in the centre of this pic with the two black multi-point connectors on top:



If it is, then it isn't specifically related to fuel pumping, and I've never heard of it 'buzzing'.

 

[Shadeyman]

I think he means the main ECU that sits on top of the throttle body - shown in the centre of this pic with the two black multi-point connectors on top:

View attachment 97116

If it is, then it isn't specifically related to fuel pumping, and I've never heard of it 'buzzing'.

The ePER lists it as a "Injection Control Unit" (its what most of us call the "Engine ECU" I think".

Agreed, it deffinately shouldn't be buzzing, don't think there's anything in it that could make a buzzing sound thats why I suggested it could be the throttle thats making the noise as the "Injection Control Unit" sits right on top of it.

Hope its not the "Fuel Control Unit" as they're over a £1000 new.

 

[Daytona600]

Hi cheers for the quick reply, and it's the number 6 on the digram which is making the noise and relearn proceedure ? And I will put the pic of what is making the noise.

 

[Daytona600]

And I just went and had another listen to it and it anit a buzzing noise but maybe either a shorting noise or liked a pump sucking air??

 

[yellowstilo]

the throttle body right under your ecu is powered by a pulse with modulation signal, this means the DC motor for controlling the position of the butterfly flap (?) is switched on and off with a high frequency, the time for off- and on determines the opening percentage of the throttle.
This can be heard as a high pitched sound from the moment the key is turned to the "on" position.
I can't imagine the ecu produces any sound, it 's only a box with electronic parts....

 

[Daytona600]

Ok that does make sense to me know, and ur right that it only happens when I turn it on but I can hear it when the engine is because it's to noisy? But by disconnecting all the wires on the fuse box, will this cause this problem? And if so how do I fix it mate? Cheers

 

[Shadeyman]

See post 2.

 

[yellowstilo]

Ok that does make sense to me know, and ur right that it only happens when I turn it on but I can hear it when the engine is because it's to noisy? But by disconnecting all the wires on the fuse box, will this cause this problem? And if so how do I fix it mate? Cheers

try a throttle body relearn:

key on, don't touch any pedal
wait for 1 minute (don't touch anything)
key off - wait 30 seconds (learned data are stored in eeprom)
ready !

 

[Daytona600]

Ok I will try tomorrow in the morning and I will let u both know how I get on but 1 more thing do I turn on the engine or just on? Cheers

 

[wp3zza]

Hiya mate. I have a 02 stilo abarth (pic in gallery) & its always had the same high pitched wine seemingly from the ECU on turning the ignition to MAR. I would suggest its perfectly normal and don't try tinkering with any connections. As long as your car starts and drives fine with no error messages on the dash you've got nothing to worry about. I presume its a stilo abarth your talking about. Other peoples opinions are fairly worthless (no offense) unless they have experience with the same vehicle.... Hope this helps

 

[Daytona600]

Hiya mate. I have a 02 stilo abarth (pic in gallery) & its always had the same high pitched wine seemingly from the ECU on turning the ignition to MAR. I would suggest its perfectly normal and don't try tinkering with any connections. As long as your car starts and drives fine with no error messages on the dash you've got nothing to worry about. I presume its a stilo abarth your talking about. Other peoples opinions are fairly worthless (no offense) unless they have experience with the same vehicle.... Hope this helps

Hi well it does start first time and the engine light isn't on, on the dash.
But I've never heard this noise before and I've had it for about a year now? It started after I disconnect the plugs from the fuse box to get to the dame light! Was yours making the same noise when you bought it?

 

[wp3zza]

Yeah mines always been the same, however I have had the battery on and off a thousand times when works being done. Try the magic 'throttle re-learn' if you like but as long as she runs sweet with errors flashing on the dash u aint gotta problem trust me. The best thing you can do if you plan to keep the car is to invest in a usb to vag com cable (£20 ebay) and fiatecusan software (£50 full version download). This will enable you to diagnose any engine/gearbox fault using your laptop. A must for any serious fiat owner

 

[Daytona600]

And your car has never had no problem with the noise? And I've had the battery out a few times as well? And never before the noise? Il see if the throttle relearn stops the noise.
And yes I was thinking of getting one because my gf ****ty corsa has a engine fault? And it is cheaper in the long run.

 

[yellowstilo]

personally i don't think a throttle body relearn will stop the high-pitch buzzing sound, that's just the way the damn thing works - the frequency of switching it on-off very fast generates this specific sound, nothing to worry about really....

 

[Daytona600]

Hi I've tried the relearn thing and no joy and also put some fuel in it and still the same noise, but u can't hear it when the bonnet is closed so I'm guessing it must be normal but thank you for all your help every one