problems - United Bimmer Community

**Beelzibub** · 07-07-2005, 10:44 AM

For the last couple of weeks my 98 523 (2.5 ltr m52) has been running crappy at idle. I sprayed a bit of carb cleaner around the inlet manifold and the revs increased slightly - obviously needed a new manifold gasket then!! I've had this replaced today and tried the old carb cleaner test again - no leak, then why the bloody hell does she still idle like a bag of crap???? Idle control valve is likely a culprit but the thing is sometimes she will settle at idle perfeclty and I have to keep revving her to get the bad idle again, other times she will just consistently idle badly - does this sound like an idle control valve issue??? I thought they just died or can they just get a bit sticky? I disconnected the MAF and the idle problem went away, however after driving home with the MAF disconnected the idle problem returned. This might sound stupid but the problem always seems worse when I put her on my steep drive nose facing down <wtf??

Also there is an incessent rattle from the exhaust somewhere which started about 7-8 weeks ago as a little tinkling but now is a major rattle when the engine is started/revved. Last week I had a new hi flow Stainless cat, center box and rear box fitted not just because I thought it would aliviate this problem but because I had promised myself a stainless system for a while. The exhaust was a custom job and uses the down pipes from the original cat, is there anything in these down pipes that could cause a rattle - ie are they double skinned or something or can anyone think of a possible problem with the manifolds??? She had new manifold gaskets about 3 months ago. Just to let you know what the rattle sounds like, it really sounds as if a heat sheild is loose, but this isn't the case, all are in place firmly.

Any help appreciated

**devinwwu** · 07-07-2005, 01:07 PM

my guess is its the Idle Control Valve, you can usually find these in junkyards for fairly cheap for that engine cause they are fairly common. look around locally for people parting them out, i know that up here in WA we have quite a few bmw's people end up parting. Sign up on your local BMWCCA chapter and post a thread there asking for the part as well. a lot of times there is some guy who has hella parts lyin around and chances are they'll have that as well.

As far as the rattle, get your car up on a lift or jack it up and shake each section of the exhaust or use the old screwdriver to the ear technique in several places. it may not even be the actual pipe, it could likely be a heat shield that's missing a bolt. happened on my old roomates wrx when we changed the turbo.

**komodo** · 07-07-2005, 10:14 PM

You can also get your ICV cleaned for about $20 without replacing it.

**devinwwu** · 07-08-2005, 12:33 AM

you could always clean it yourself too and save even more. if i'm not mistaken they always have these things on ebay too

**Beelzibub** · 07-08-2005, 08:33 AM

Cheers for the replies.

On the rattle issue I am having new stainless downpipes fitted next week, if that doesn't cure it new stainless polished manifolds will be the order of the day if they don't cure it I will hang myself. It's def not a heat sheild I've had at least 15 mechs take a look at it over the last 8-9 days and all of them are confident that it's a heat shield, come out with a gigantic screwdriver and start poking and prodding around then say "maybe it's not a heat sheild then". At one stage I had a mech standing under the center box, one under the CAT, and one under the engine/downpipes - each of them said the rattle was coming from their allocated part of the system!!!!! Anyway due to the replacement of the entire system from the downpipes back it cannot emit from there.

On the idle problem I don't know what my next move will be yet.