FL S8: Airfilter box gone Boombox
 

Hi all.

Just spent an hour listening to the engine while idling:rolleyes:

I've always since i bought the car 2 yrs ago felt like there was a strange repeatedly *thump* when listening closely to the engine while bonnet is open.
While doing a check for intake leaks regarding the 17549 code by emptying a bottle of Start Gas on all places where it would be possible to suck some in.( no chance there is any leak..) i noticed after removing the cold air intake pipe that the boombox *thump* comes from inside the airfilter box..

Anyone else experienced this?

From the good old days i would call this backfire caused by the timingbelt not in the right position but since car runs perfect it has to be something else. only issue is "auto-reving 3 times to apx 1800 rpm at coldstart before setling down. This started with the 17549 code appearing.


So, any good ideas gents? :)

Hi mine does this as well I just put it down to the air pump in the air box and didn't bother to investigate any further.

Noticed that the other day while cleaning my MAF sensor; what's it for? :Confused:

Its my pet hate :)
That pump is purely there to feed fresh air into the exaust just before the headers. It does this for a short time (few minutes?) on a cold start to ignite unburned fuel in the exaust and heat up the cats quicker, so that the D2 FL can achieve a Euro III emissions standard.
I hate complications added just to satisfy emissions.

of course this is not nearly as bad as gas recirculation on other cars (mostly diesels), which feeds the hot, dirty exaust gasses back into the intake manifold. what a terrible idea!