Acceleration 'interference' noise

[ikickass]

A strange noise has recently become noticeable under acceleration on my Seat Leon 1.9tdi (90bhp) ('51plate).

Basically at around about the 1.5k-2k revs mark there is a noise from the accelerator that sounds like 'interference'. It sounds like something electronic – almost like two electric wires a being placed together or the ‘interference’ from a radio. I honestly can’t really explain what it sounds like any better than that.

I can drown it out by turning the stereo up but even then I can hear it in the background.

It doesn’t just occur when the revs reach the above level – I can be driving along without the noise, then when the car reaches an incline it will start. Almost as if once the engine works harder, the noise starts.

The noise didn’t occur before I had the cam-belt and water pump changed 10 days ago. Would this have anything to do with it?

The car is under a warranty (as I brought it 2nd hand recently) but the garage doesn’t seem to know what it is.

Any help or advice as to what to look at would be gratefully received.

 

[craig-pd130]

Is it definitely coming from the throttle pedal area? It could just be a spring or clip rattling, or maybe a bit of loose trim in the engine bay.

If it was something electrical I would think you'd see a check engine light. Have a look under the bonnet and in the footwell with the engine running, and get someone to rev the engine in neutral. See if you can spot the noise source.

 

[ikickass]

Thanks for the reply.

I've taken it to the garage who did the cambelt change. They seemed to think it wasn't related to that as if it were it would make the noise all the time the engine as running (even when revved in neutral)- not just when moving and between certain revs.

He looked under the bonnet and checked a few things but was at a loss. He seemed to think that it was coming from inside the car - something I agree with.

I'll check all the clips etc all around the pedal but have booked it into the Honda dealership (it's covered for 12 months at any Honda dealer) and I must say that out of all the dealerships I've been to they were the most helpful I've ever met. They've booked it in for Friday for me to take it out on a demonstration test drive. (SEAT could really take a few lessons from Honda customer care IMO).

I'll keep you posted on developments just in case anyone else has a similar problem in the future.

 

[Goot]

Can you take an audio recording of it? Interesting to know if it sounds like my "noise"

Goot

 

[ikickass]

I'll have a see if I can record it later - although I'm not overly tech-savvy so have no idea how (will try to rig mobile up to computer later).

Other than the above description my mechanic described it as sounding like a faint spinning of a revolver - obviously I wouldn't know!

 

[muddyboots]

Could be related to the (ventilation) fan blades - maybe there is a leaf stuck of there's some play in the fan shaft, and when the car accelerates, the blades are touching something.

Try turning the fan off completely and see if it stops.

 

[Goot]

Right, this "revolver" sound. It's driving me nuts. Really notice it more now that I'm running Shell Diesel Extra (was on long term BP Ultimate). I need to get to the bottom of it.

Sometimes hear it faintly when the car is idling and out of gear but usually only when accelerating and in gear (in neutral you can't hear it). Doesn't matter what speed or gear engaged - but you notice more when engine noise is low.

I'm going to try and take some audio of it. Quite difficult as the "diesel sound" muffles it on a recording.

Goot

 

[ikickass]

Sorry for delay in replying.

I've had my Leon checked out by everyone I can think of but because the noise only occurs when moving it kinda narrows it down with regards to what anyone can do.

To cut a long story short I took the car to Jamsport, Northampton to use their rolling road to try and get to the bottom of it. They couldn't. They did state that when he jammed his foot right up behind the dash it stopped and that it was in his opinion internal. He checked everything regarding the turbo as from my description he thought maybe it only occured when the turbo kicked in but saw nothing unusual. I have come to the conclusion that it is a 'rattle' from behind the dashboard and there's nothing I can do to stop it. I've wedged stuff up behind the dash but nothing can stop it.

It's not fan / heater related as I've already tried every combination of on / off imaginable...

'My' noise occurs regardless of fuel - whether it's BP Ultimate or Supermarket stuff. There is no difference in the sound of the noise either (perhaps more evidence that it's internal?).

If anyone gets to the bottom of it, PLEASE let me know for my own sanity!

PS: It was recommended on another forum to check the 'clips' on the exhaust directly underneath the handbrake. Apparently this can create a similar noise (happened to posters Skoda Octavia)

 

[Tom B]

Sounds like an earthing issue to me!

 

[ikickass]

How do you mean earthing issue? (sorry not mechanically knowledgable).

 

[Scotty2hotty]

I am getting the exact same noise from my accelerator. When accelerating to 1.2 to 2k revs, the clicking/interference/hard drive clicking sound starts, then stops or quietens higher up the rev range.

I am at a loss as to what is casuing it, I can not localise the sound, but it sounds almost as if it is either behind the dash or behind the accelerator pedal. The noise does not occur in neutral, so I cant have someone look in the engine bay whilst revving, as it only makes this noise in gear