Hi all,

I'm hoping you can help me identify this sound from my engine. On cold startups, it sounds like this for about the first minute. My first thought is that the turbo isn't getting / holding oil? No spots on the ground, and it sounds fine after a minute.

IMG_1381.MOV - YouTube

 

guessing SAI pump. I'm pretty sure your car has one. blows air into the exhaust stream until the cats warm up to control cold emissions. the general thinking is that if it is making noise, it is working. pricey part to replace.

 

Does this sound go away after the needle on the temp gauge reaches the first or second notch (warms up)? If so, it is more than likely the SAI pump (secondary air injection pump) which serves the purpose of "injecting" oxygen into the exhaust system to heat the cat converters up to help with emissions until the engine is warm and can properly lean down. You can see the pump from underneath of the car right next to the oil filter (if i remember correctly). Try jacking it up and cold starting it and put your hand on/ ear next to the pump to confirm it. Finding a used pump would be your best bet from a wrecked/part car since they are very pricey. Let us know your findings !

 

Thanks guys -- The sound goes away in about a minute (55 seconds), not just when the needle starts going up. The RPM sit at about 1,250. Additionally the engine starts smoothing out about 3 minutes later when the RPMs drop to ~900 as I'm assuming the engine warms up.

In looking at a handful of other posts / youTube vids, it sounds EXACTLY like other 1.8T cars. Seems a common point of failure for the SAI is the housing rivets stretching/stripping allowing gaps to develop. It seems like they can be drilled out and replaced with bolts/nuts. I went to look under the car and of course, there's a full plastic sheet covering everything up so I can't see if I can pull it myself w/o a lift.

Does the TT share the same SAI pump as other 1.8T engines?

 

Don't worry it's just the gremlins munching on your wires... nothing major!


P.S. You'd get a CEL if your SAI was on the fritz, or it'd sound like were mice living in the front pass door/footwel area.