Nasty air pump! - The Unofficial BMW M5 Messageboard (m5board.com)

holtsaber · 3rd April 2006, 22:19

My 1992 3.6 has the not uncommon problem of a grumbling air pump.
Over the last 6 months, it seems to have got much worse, and from cold the engine now has to be run for 5 minutes and re-started to make it go quiet!

Looking at the mechanics of the system, I see that the clutch that drives the pump is controlled by a relay which also feeds the vacuum pump.
If I remove this relay, or the fuse for this circuit, I am hoping that my noise will stop.

Does anybody know where either the relay or the fuse for this circuit is located?

If anyone has had a similar problem or found an alternative cure, I would love to hear from you........

Thanks,

Adam

graham4242 · 3rd April 2006, 23:54

Don't know if its the same as the 3.8 but in the cold the air the pump that comes on (to re-use the heat from the exhust) does sound very rough but a blip of the throttle makes it go away. Plus best not to let it idle just get in a go. Apologies if I've got the wronge end on the stick.

holtsaber · 4th April 2006, 00:11

I think it is the same on the 3.8, but the purpose of the pump is to pump air into the exhaust manifold the help to reduce emissions and also reduce condensation in the cat?

As far as I'm aware, there would be no detrimental effect on the car if the pump was taken out of circuit, but I just don't know where the relay is located.......

Phlem5 · 4th April 2006, 00:19

I think you can remove the drive belt as a quick solution, if I remember correctly ??.

Phil.

holtsaber · 4th April 2006, 00:24

That certainly would be one option if the belt isn't driving anything else, but in typical M5 fashion, it's just about impossible to get at!

joost · 4th April 2006, 00:48

the belt is easy to release, but it's also for the airco pump

holtsaber · 4th April 2006, 01:04

I don't want to lose the aircon with the 'warm weather' (haha) coming up, but I think I may have found an answer from an old post.

Apparantly the controlling relay is under the bonnet below a plastic cover next to the DME? unit. If I remove this relay then my beast will no longer resemble a tractor!

Donati · 4th April 2006, 01:42

Quote:

Originally Posted by holtsaber

I don't want to lose the aircon with the 'warm weather' (haha) coming up, but I think I may have found an answer from an old post.

Apparantly the controlling relay is under the bonnet below a plastic cover next to the DME? unit. If I remove this relay then my beast will no longer resemble a tractor!

Completely correct..
Simply remove the relay under the dme plastic cover.. there are 3 relays in a row there, and its the one closest to the engine.. just pull it out, and the airpump will not engage at all.. plus: no side effects.
I did it on both my 3.6's.. hated the noise of that pump.. and dont really care if pullution is bit over regulations for the first 2min..

I have the electric diagrams somewhere, if you need it..