WTF is this noise?

[rspi]

The SAS pump pulls air from the airbox and feeds it to the exhaust, with the goal of getting more oxygen into the catalytic converter...

Very good, thank you sir.

[erikv11]

^^That makes excellent sense, and definitely matches with the symptoms I'm experiencing. Did I read somewhere that without it, your engine will run a bit lean on cold start?

The air pump only affects the exhaust stream, has nothing to do with the intake, so it can not cause the engine to run lean or rich. It is strictly an emissions device.

The reason the air pump has a connection to the air box is so the air going into the pump is filtered.

That whining pump is probably full of water, this is the way the typically die. The SAS valve wears out and gets stuck open, moist exhaust feeds constantly backwards into the pump, water condenses and it literally fills up. If you decide to fix it then be sure to also get a new (or at least working) SAS valve.

Or get rid of the whole SAS.

[scot850]

Try removing the pump and drilling an 1/8" hole in the bottom of the casing and let all the water out. Spray inside the hole with WD-40 or similar. Replace the SAS valve up by the turbo (fiddly but not too hard) and see what happens. You can try running the car without replacing the valve and see if the pump can settle down with the TLC before swapping the valve out. That way you will know if you have to change out both parts.

Or delete the SAS....!

Neil.

[slupul]

Tested the SAS pump by jumping the relay, as per this post on Volvospeed: volvospeed.com/vs_forum/topic/40880-how-do-you-test-the-air-pump/

Worked! Without a doubt that god awful noise is the air pump. Now to delete the SAS I suppose? Screw paying $400 for parts to fix the damn thing....

[scot850]

Don't have to buy new. I bought a re-conditioned one on ebay and it was about $130 US about 4 years ago. You could also try Chapman motors on Vancouver Island. Not the cheapest, but the have never sent me a junk part. Or you could delete....

Neil.