Bad Vacuum Pump? E89 2.0 N20 (2013)

[jonrx7uk]

I've noticed a bad knocking coming from the vacuum pump recently (diagnosed using the long screwdriver in the ear technique ). I've removed the pump to see if anything obvious is broken but all looked good. Once refitted the noise went away, but after 2 mins came back.

The car has the electronic turbo solenoid so the vacuum pump only provides vacuum for the brake servo and exhaust flap. Whist pulling the pipe off that feeds the exhaust flap (there is a split in the engine bay next to the NSF strut tower) there is slight vacuum but not enough to operate the flap. Increasing the revs doesn't increase the vacuum either.

Has anybody else experienced this or can confirm how much vacuum they're getting?

Whilst doing some research it appears that BMW recalled all 2013 and earlier N20 cars in the US for a bad oil supply to the vacuum pump (that ultimately could cause brake failure), and a re-profiled end to the intake camshaft was installed on later models allowing better oil flow to the pump. Doing the checks mine has the older camshaft

Regards

[Pbondar]

Hello, I’m not aware of anyone posting on this forum this issue...looking at TIS it looks like they use a complex special tool to do troubleshooting...

I would think if you can’t spot a leak and it’s not working it’s either visit a specialist or buy a new pump?

[tintoverano]

perhaps fuel trims could be checked as well, the DME would compensate for vacuum leak, at least it does when there's "real" leak

[jonrx7uk]

Sorted, 2nd hand vacuum pump has cured the knocking.

Regards

[Pbondar]

Good result...was it easy to replace?

[jonrx7uk]

One of the simplest jobs I've done. 3 torx bolts & 2 vac pipes. A lot easier on our cars than say a 3 series because we don't have to remove the scuttle covering the back of the engine.

Regards