Suspecting Vacuum leak...

[e34.535i.sport]

I've had a strange whistle noise developing over the past few weeks coming from somewhere i the general vicinity of the throttle linkage/intake manifold (I know that is a big area)... It happens when I release the throttle and at idle, although it is sporadic and random.

Other info that may be useful is that I have had a particularly rough idle for some time (Recent EAT chip improved it a little though), and it doesn't seem to have the same performance as it did when I got it (EAT chip has also improved this!).

After a lot of reading around it seems to suggest a vaccum leak - Pgrindstaff has been kind enough to reply to a PM I sent him as in one of his threads he describes symptoms exactly like mine.

I was hoping someone with m30 knowledge may be able to direct me to the vaccum hoses to check, or how I can differentiate these from other hoses at least so I can go find them and make sure there's no cracks etc, before looking at the intake manifold gasket. If there's anything else please suggest, and what methods I can use to check things as I'm fairly new to this vacuum business...

Pgrindstaff has suggested this small hose could be the issue and I am sure I have read this commonly causes a problem on the m30...
http://www.bimmernut.com/forum/showt...ht=vacuum+hose

Oh and can I ask is this problem an urgent one to sort out? I'm assuming its ok to drive as long as there's no running problems - I just don't want to cause any damage by driving it with a vacuum leak...

TIA...

[whiskychaser]

Dont think its life and death but it may affect your mpg. Have you tried one of those carb cleaner sprays? I think the idea is you spray flammable cleaner on the suspect area and if your revs change you found the culprit

[e34.535i.sport]

Dont think its life and death but it may affect your mpg. Have you tried one of those carb cleaner sprays? I think the idea is you spray flammable cleaner on the suspect area and if your revs change you found the culprit

Hey you have a point there, I do get less mpg than I did when I bought it... Thanks for the spray idea, sounds like a plan... Just need to narrow it down a bit first I think...

[whiskychaser]

Hey you have a point there, I do get less mpg than I did when I bought it... Thanks for the spray idea, sounds like a plan... Just need to narrow it down a bit first I think...

Its good round the manifold area. So I hear. But dont go using your gas lighter refill cos its handy

[e34.535i.sport]

I had a leak from the fuel regulator on top of the engine block and it also made weird noises. Check that too, especially the small hose coming in from the passenger side.

Its funny you should say that becasue the FPR has been making wierd noises lately but seems to have quietened down and replaced by the whistle! I'll check that too thanks!

[Sixdown]

I had a leak from the fuel regulator on top of the engine block and it also made weird noises. Check that too, especially the small hose coming in from the passenger side.

[e34.535i.sport]

Hey guys, checked the two hoses that go through the manifold (one leads to the FPR and the other to the throttle body) I.e the two top purple ones in this pic...

*Courtesy of Gale - thanks!

I cant seem to find this 'Chrarcoal Cannister' vacuum line though, can anyone direct me to it? Never even heard of it before seeing this thread...

Had a look as well as I could at the intake gaskets and they seem ok, but there's definitely a gap somewhere...

Going to get some carb cleaner and spray it around a bit... Not too worried about the gasket job(if it is that) after doing some reading around. Thinking of doing injectors too if I end up doing the intake as they're a bit noisy at the moment.

The search continues.

[whiskychaser]

The search continues.

Fck. With a diagram like that you have to be a teacher!!!

[e34.535i.sport]

Fck. With a diagram like that you have to be a teacher!!!

LOL- If I had drew it you wouldn't be saying that believe me!!!!!

[whiskychaser]

LOL- If I had drew it you wouldn't be saying that believe me!!!!!

If I had drew it? I'm sure you didnt mean that sir