Noise on startup, goes after 30 seconds

[moorej91]

Hi, This is my first time on here. I purchased a 2.0 omega estate automatic about 3 weeks ago. When I first start the car up there is a "whurring" sound for about 20 to 30 seconds then it stops and is quiet. It is not engine rev related and does not seem to affect engine performance. Over the last couple of days it seem to get worse. It has been mentioned that it might be the fuel system pressurising itself.
Any help would be appreciated.

[Chopsdad]

Does the noise come from the engine bay? or could it be the vents opening inside the cab for the air con system?

[Craig_R]

The one thing i can think of it being is the secondary air injector pump is on its way out

Dont worry about replacing it do some searches on secondard air injector pumps and you will know what i mean

[Matchless]

It sounds like the secondary air injection pump mounted under the front of nearside front wing. The bearings in these get noisy. Find the pump, its above the horns, reach up and there is a connector on top of it. Unplug the cable and see if that stops the noise.
You dont need this system for Mot so can leave it disconnected but its best to blank-off the pipe where it leads to the exhaust manifold.

[wastedperfection]

Mine does it (2.5v6 manual)

Isnt it the fan just doing some sort of self test?

It is definitely coming from the fan that cools the engine

Matt

[TheBoy]

Mine does it (2.5v6 manual)

Isnt it the fan just doing some sort of self test?

It is definitely coming from the fan that cools the engine

Matt

Are you sure?  Secondary Air Injection pump, as described by Matchless above, is the most likely candidate...

[Dazzler]

Secondary Air Injection pump, as described by Matchless above, is the most likely candidate...

I agree, mine does exactly the same, nothing to worry about

[STMO123]

....only when it's cold outside.

[Matchless]

....only when it's cold outside.

No. The ECU will turn the pump on at every start-up and turns it off when lambda sensors start working properly or a time-out occurs, whichever is the soonest.
Takes longer to heat the exhaust and lambdas when its cold so pump will run for longer.

[moorej91]

Thankyou for everyones reply, wish I had joined sooner. I am not exactly sure where the noise is coming from, but it does sound like it is more to the nearside front wing as suggested by some of you. Will it be a problem if it fails, will it let me down. I dont know wether it is connected but The engine electronics warning light came on today and stayed on. When I restarted the car after about 2 hours the light went out as usual.
Could this be a problem waiting to happen. How much could I expect to pay if it is the secondary air pump? Could you tell me of a reliable garage in the cannock staffs area that do a good job and are competitively priced.

Thanks again all

[rpont]

Could be a hole in the air hose that goes from the vacuum valve mounted at the top of the radiator fan to the non return valve. Mine has failed twice and always blew the hole in the underside so that you couldn't see it. Eventually discovered that the metal non return valve had failed allowing hot exhaust gasses to the pipe.

[TheBoy]

Thankyou for everyones reply, wish I had joined sooner. I am not exactly sure where the noise is coming from, but it does sound like it is more to the nearside front wing as suggested by some of you. Will it be a problem if it fails, will it let me down. I dont know wether it is connected but The engine electronics warning light came on today and stayed on. When I restarted the car after about 2 hours the light went out as usual.
Could this be a problem waiting to happen. How much could I expect to pay if it is the secondary air pump? Could you tell me of a reliable garage in the cannock staffs area that do a good job and are competitively priced.

Thanks again all

To find out why eml came on, do the 'paperclip test' and report codes back here...

[moorej91]

I used to do the maintanence on all my old cars when I was younger, but not recently. Could you tell me what the "paperclip test" is, I pressume its to short out and overide something but what.

Regards

[TheBoy]

I used to do the maintanence on all my old cars when I was younger, but not recently. Could you tell me what the "paperclip test" is, I pressume its to short out and overide something but what.

Regards

Yes, details in FAQ section

[curly]

hi there,the noise you are expereancing on start up is the secondary pump that runs for anything up to 60 seconds depending on out side temp,from inner wheel arch area that actually is a cat converter pre heater so it gets the cat/s warmed up quicker than the engine can to bring the lamda sensors in operation quicker and thus gives you economy and low emissions in a reasonably quick time,and stops it running to rich,which is why when you start up the idle should be about 1200rpm,then when pump stops drops to850rpm,then temp gauge moves up normal 700rpm (v6)so it stops stalling through ecu,so in a nutshell perfectly normal on all models inc vectra/astra,hopr this helps you ,good luck,curly.