Strange Whistle on Cold Start

[Serb404]

Every cold start I get a minor small whistle first few minutes of driving in between 1.5 - 2.0 rpms, it's nothing crazy and goes away after a bit.

I replaced my boot already so it's not that, just curious has anyone had any similar issues only on a cold start, sounds like a supercharger

[X5chemist]

It's likely the secondary air injection pump. Mine whistled at cold start up too. Eventually, it threw a code for it too. Tried three different air pumps. Finally, a third pump turned off the code. I'll have to look up the brand. It was RockAuto most expensive air pump.

[80stech]

The auxiliary air pump will make a vacuum cleaner like noise on cold start but you should notice that without the car moving as well.

[Serb404]

Originally Posted by X5chemist

It's likely the secondary air injection pump. Mine whistled at cold start up too. Eventually, it threw a code for it too. Tried three different air pumps. Finally, a third pump turned off the code. I'll have to look up the brand. It was RockAuto most expensive air pump.

only happens when I drive the car, I don't think it's the air injection pump

Originally Posted by 80stech

The auxiliary air pump will make a vacuum cleaner like noise on cold start but you should notice that without the car moving as well.

only happens when I drive the car, on idle she's perfectly quiet and no issues

[Serb404]

Would this be a possible fix as well?

https://www.youtube.com/watch?v=Pm9VNP7ezTs

[X5chemist]

The code on mine cleared with a HELLA*728124190.

Check the air injection pump hoses.


https://www.youtube.com/watch?v=k400njcEvA0

[Serb404]

Originally Posted by X5chemist

The code on mine cleared with a HELLA*728124190.

Check the air injection pump hoses.


https://www.youtube.com/watch?v=k400njcEvA0

thanks I'll check that this afternoon, not getting any codes on the dash either though

[80stech]

I guess it's possible that the air pump might only be noisy if there is extra back pressure from the exhaust ?? Does it seem to change with that in mind ? (on coast or accel)

You should be able to hear the air pump running on a cold start and then maybe listen for when it quits before driving away so you get an idea of what it sounds like.

[andrewwynn]

There is the valve that goes from sap into the exhaust. If that isn't opening full or some other issue I could see it making a whistle. Too coincidental of the cold start and 90-120 seconds to really be anything not sap related.

Usually the bearing fails and it will make a horrendous noise like the car is trying to hover.

[Serb404]

Originally Posted by 80stech

I guess it's possible that the air pump might only be noisy if there is extra back pressure from the exhaust ?? Does it seem to change with that in mind ? (on coast or accel)

You should be able to hear the air pump running on a cold start and then maybe listen for when it quits before driving away so you get an idea of what it sounds like.

Air Pump runs perfectly, no whistle noise from that at idle, when I'm coasting around 1.5 rpm it makes a slight whistle, goes away after 5 minutes of driving, I can try to grab a video of it possible to help further diagnose

Originally Posted by andrewwynn

There is the valve that goes from sap into the exhaust. If that isn't opening full or some other issue I could see it making a whistle. Too coincidental of the cold start and 90-120 seconds to really be anything not sap related.

Usually the bearing fails and it will make a horrendous noise like the car is trying to hover.

yeah I've had that replaced a long time ago I believe, it was a horrendous sqeaking noise on cold starts, was extremely bad in the winter too