Engine noise upon startup ? Help

[schultz318]

I have a 99 318ti, upon cold startup the engine idles fine when what sounds like the ac pump kicks in (very noisy). It last for approxmiatly 20 seconds then kicks out and everthing is normal. Only cold startups though, warm engine doesn't do it. I know it isn't the ac pump because I have the air off. I'm relatively new to the BMW so any advice or ideas would be greatly appreciated. Thanks

[ultralinear]

It's very likely the secondary air pump. If it hasn't gotten lots louder and it goes away in 20 seconds or so, then no worries...

[ZeroG]

Originally Posted by schultz318

I have a 99 318ti, upon cold startup the engine idles fine when what sounds like the ac pump kicks in (very noisy). It last for approxmiatly 20 seconds then kicks out and everthing is normal. Only cold startups though, warm engine doesn't do it. I know it isn't the ac pump because I have the air off. I'm relatively new to the BMW so any advice or ideas would be greatly appreciated. Thanks

My car is the same year and does the same thing in the mornings. It is the Throttle Body Heater. Next time you start your car in the cold pop the hood and stick your head by the TB and you'll see.

-Chad

[m-technik_ti]

Originally Posted by ZeroG

My car is the same year and does the same thing in the mornings. It is the Throttle Body Heater. Next time you start your car in the cold pop the hood and stick your head by the TB and you'll see.

-Chad

hmmmm. interesting. My ti does the same thing...I thought it may have been coming from the throttle body.

[schultz318]

Thanks for the info and fast response guys,,,sounds like its a normal thing. Like I said I'm new to the BMW and any advice would be greatly appreciated.

[James]

Hello guys, whenever you have problems related to cold, talk to me, I'm from Ottawa Canada, it's f.... and cold here. Anyway, I've had the same problem a couple of years ago, the car was still under warranty, and on cold start -10C and colder, I would get this strange noise on start up for only about 10 to 20 seconds. It was the starter, when deploying into the engine gear to turn engine, it would not completely retrieve from gear, it sounded like starting a car already started.

try that.
James