Mystery Noise

[younglion]

Hi guys got a small problem with my 1999 VT when i accelerate a sound comes out of the air vent it sounds like air leaking from somewhere, but its only when i accelerate, myabe its the carbon build up in the throttle body but not sure? anyone else have this problem?

 

[naf33n]

i dunno personally. what motor is it, it might help narrow it down

 

[accentstencil]

Could be a leak from the vent position selector switch or a vacuum hose on the heater control panel. Check to see if you can hear a hissing noise when you select different vent positions with the engine off. If there is no hiss I would say that is the problem.

 

[WinterVX]

I have the same noise while under soft acceleration from under the glove box area...and just yesterday when i started the car up it was running quite rough for a good 30 seconds or so till i pumped the accelerator a few times and cleared it up. It was the same noise and was comin from the same area while not in motion.

Ill have to check that your suggestion out Accent, it comes from the fan area as stated beneath the glove box, but doesnt matter if the fan is on or not, or in any different position. Even when I flick the air con on, i get a slight hissing noise for a few seconds while it kicks in, couldnt be a leak cause the air still gets cold as it should.

 

[accentstencil]

I have the same noise while under soft acceleration from under the glove box area...and just yesterday when i started the car up it was running quite rough for a good 30 seconds or so till i pumped the accelerator a few times and cleared it up. It was the same noise and was comin from the same area while not in motion.

Ill have to check that your suggestion out Accent, it comes from the fan area as stated beneath the glove box, but doesnt matter if the fan is on or not, or in any different position. Even when I flick the air con on, i get a slight hissing noise for a few seconds while it kicks in, couldnt be a leak cause the air still gets cold as it should.

The vacuum tank is situated near the glovebox and it could be leaking or have a loose hose. The vacuum in the tank is used by the vent switch to select the vent positions. If it is leaking it won't store the vacuum and there fore won't alter the vent positions when the engine is off, at least until the vacuum runs out.

 

[WinterVX]

I can change the vent positions fine when the car is off, but after a few changes back and fourth along the line, it will then stop working till I start the car again.

Deffinately a leak in there then?

and would that cause the rough idle and leaking noise I heard last night till i hit the accelerator a few times and cleared it up?

 

[accentstencil]

Sounds like the vacuum tank is OK. Must be some other problem, but I can't think of anything else.

 

[WinterVX]

Still sounds like a loose connection around that area tho, thats where the noise comes from while under soft acceleration. Ill have it checked out when I get a chance.

 

[accentstencil]

There is a hose that goes from the vacuum tank to the engine to create the vacuum. If that is leaking maybe it could make it run rough, I don't really know.

 

[younglion]

i got my car serviced and they fixed it it was the purge hose which i suspected, atleast they picked up on that seeing as they didnt even check my lights and still ticked ok on the report, funny thing was the parkers and tail lights werent working when i took it there. Dodgy bastards, wont be taking it back to them again..... bloody automasters, shouldve known not to take it to them,