E46 316i idiling problem?

Hi all,
    Our 99 E46 316i isn't idling properly, on start up she goes to 1,100rpm and then falls to around 600/700 but doesn't idle properly.

I've been told it could be the Mass Air Flow Meter (which isn't cheap )

Its defintly not the head gasket or anything as she doens't overheat or anything.

Any other ideas or is the advice correct?

Will get it taken to a specialist sometime soon!

No it seems to be right from start up, it'll idle at around 1,000/1,100rpm before dropping to 600/700

My E46 328i idles erratically when cold going from 800 down to 600 where it recovers back to 800

But sits on 700rpm when idle and war,

that for me or aidan?

It's for the E46 328i.

BMW deny there is a problem - but they made the mapping of the ECU too tight - as a result of wear in Vanos it causes the problem while it is performing it's warm up phase with EGR active.

When it warms that part of the "map" is not used - and idle stabilises. It affects power and general performance too -- major problem with M52TU's

It's an expensive job to do properly - don't let a muppet do it...

BMWcare
bmwcare@eircom.net

I've seen this on another forum and the general advice is to clean the idle control thingy.
Something I plan to do soon as I have the same problem with my 325

Starfury wrote: What will happen if I just leave it? Its been doing it for a couple years now... Everything else seems fine.

It will be ok if left alone.
Just not 100%.

No - don't bother doing that...

It's PHYSICAL WEAR of the Vanos Unit (ASSUMING A FULL PROPER DIAGNOSTIC CONFIRMS VANOS). The mapping can't compensate -- chipping does not fix EGR or Vanos faults. In fact - chipping any car is often silly without proper mods. The 328 is underpowered but due mainly to intake restriction. There's a reason for 193bhp - most produce more anyway.

Only a replacement of the Vanos is a proper cure. Chip it then if you want -
When I have issues with chipped cars I've normally got to remove the chip BEFORE any proper diagnosis can be done -- when repaired I won't refit the chip -- customer signs that car is fixed, then they can do what they like.

If I was to recommend a chip - it would only be the Diesels and only Upsolute (due to experience). If you want to do petrols -- get out a big wallet -- you need to upgrade a lot of stuff -- cheaper to buy an M or a 911...

BMWcare
bmwcare@eircom.net

The proper answer that I will have to give:

Intake Restriction: I've never done it - so I don't know
Cost: Full Diagnostic to confirm, then replace, then reset Adaptions etc. etc. properly is approx. 6-8 hours labour +parts
Benefit: MPG improved (especially on short running), Power improved (especially 2,800-3,800rpm)
Problems: None really except the opposite of the benefits for a long time - however the problem should get worse with age/wear. Technically, it could do in your chain...eventually...

"Smart Answer":
No real-world difference except a bit extra expense. Forget mods unless you get Vanos right. If you want your car right - spend the money - you'll be glad you did.

BMWcare
bmwcare@eircom.net