[holtsaber]

Hi everyone!

I'm new to the board, and have been the proud owner of a 1992 3.6 since April.
My previous was a 1994 540i, and before that was a 535. (All E34).

The M5 is the most amazing car I have ever owned. It does however have a little problem which I hope you may be able to help me with.

When I start the car in the morning, the exhaust is very noisy. It appears to be blowing fom the manifold, but it isn't. When the engine speed exceeds 2600rpm, the noise stops, but comes back when the engine speed drops again. After about 15 minutes of driving, the noise stops, and doesn't come back until the next day.

I have now discovered that if I leave it run from cold (and noisy) for a minute or two, turn the engine off and restart it, the noise is gone!

I've asked my local 'specialist' and my nearest franchise, but they have no idea what I am talking about!!
I have been led to believe that there is an air pump on the exhaust system which may be causing my problems?

Any help wouold be much appreciated.


Regards,

Adam

 

[Mfemman]

It's the airpump. The first minutes then the engine is cold, air is pumped in to the exhaust manifold. The reason for this is to spare the kats when the engine is cold and emissions level is high. All M5 E34 have the airpump. look here. http://www.realoem.com/bmw/partgrp.do?model=HD91&mospid=47385&hg=11&fg=50

 

[Sam Thake]

Yes, it does sound like the air pump. However, I understood that it should cut out after two minutes at most, rather than fifteen.??????

On mine, a quick blip of the throttle is all that's needed to stop it, before I get funny looks from the neighbours.

 

[holtsaber]

Thanks for your help. I can't even locate the pump, so I think replacing it is an unlikely option!
Is there any way of disabling the pump, or is it simply something that has to be put up with unless copious sums of cash can be poured into its repair?

Having said that, as a first time M5 owner, it's a small price to pay. What an amazing car hey?

 

[madm5]

you should hear mine immediately after starting, shocked the hell outta me when I first heard it. Does anyone know if this means it's gone or whether they were this noisy from new? Also seeing as it's driven by drive belts, how come it stops? Surely it's running all the time

 

[Simonal]

you should hear mine immediately after starting, shocked the hell outta me when I first heard it. Does anyone know if this means it's gone or whether they were this noisy from new? Also seeing as it's driven by drive belts, how come it stops? Surely it's running all the time

According to another member who had a new one fitted they should be loud if they go quiet that is when there is meant to be a problem!

If you search the forum you should find the thread where it was dicussed recently...