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Discussion Starter #1
Morning all.

As the title says, the exhaust flap on my 328i is stuck open.
Does anyone know how I can fix this, as I believe it should only open at certain times????
Is this maybe what is causing my eratic idle and bad fuel consumption??
Thanks.
 

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look underneath and you should locate an airpipe that goes into your butterfly valve, removing it is a popular mod on these, this makes the car sound better at lower revs, this will not affect the car in any way, but you need that pipe blocked, ussually by a golf tee, check this is the case, cos you need that pipe reconnecting or blocking, id block it personnelly
 

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Discussion Starter #3
My pipe was attached but the valve stuck open.
Do you know what would cause this to stop working and stay stuck open?
 

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look underneath and you should locate an airpipe that goes into your butterfly valve, removing it is a popular mod on these, this makes the car sound better at lower revs, this will not affect the car in any way, but you need that pipe blocked, ussually by a golf tee, check this is the case, cos you need that pipe reconnecting or blocking, id block it personnelly
But if the valves stuck open, whats the point blocking the pipe up ?

alexward - Put some WD40 to help free it up, then you'll just have to work it loose !
Leaving it open won't cause bad fuel consumption or an erratic idle.
 

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Discussion Starter #8
The valve/flap itself does move. I can move it with my fingers.
If I close it with my fingers, it just springs open again. It doesn't need freeing as such.
I like things to work properly on my car. I'm stickler for that.
Would rather it working properly than not. I'm not bothered about the car sounding better at low revs.
Could it be a fuse or something?
 

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No, what it sounds like is the vacuum hose that comes from the inlet manifold has spilt, perished or fallen off, which will stop that flap from closing, and will cause the bad idle and bad fuel consumption.

But from here, I can't help - I know nothing of an E46 engine bay.
 

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Discussion Starter #10
Can anyone tell me the location of this pipe under the car and in the engine bay?
Anyone had this before and fixed it?
 

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Until someone comes along who is experienced with this engine, what you can check is any rubber vacuum hose coming from the inlet manifold - You never know, you might find it yourself.

And if this is anything like the E36, the pipe runs into the fusebox and into the car, running under the carpet under the passenger seat !
 

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i just had a look under my bonnet you could have a look at the two small pipes coming from the intake hose near the MAF my guess is one of those will be the pipe that goes to the exhaust valve, to test you can disconnect one at a time and completely block it off, if this sort your idle fault im sure that will be the exhaust flap too.
 

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Discussion Starter #13
Right, i've stripped the floor in the boot out, and i've found a pipe with gushing air coming out of it! Its obviously supposed to be attched the the pipe thats going to the back box, but I cant seem to find it!
The pipe from the back box goes up into the boot floor some where, which by my guessing should be attched the loose pipe ive found with air coming out of it (when the engine is running).
Does anyone know where the pipe underneath the car from the back box goes to in the boot area? its like its been dislodged sometime.
 

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Discussion Starter #14
Right, i've stripped the floor in the boot out, and i've found a pipe with gushing air coming out of it! Its obviously supposed to be attched the the pipe thats going to the back box, but I cant seem to find it!
The pipe from the back box goes up into the boot floor some where, which by my guessing should be attched the loose pipe ive found with air coming out of it (when the engine is running).
Does anyone know where the pipe underneath the car from the back box goes to in the boot area? its like its been dislodged sometime.
I think the pipe sticking up in the boot comes from the exhaust now, but it should be attached to another pipe. But where?
 

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Discussion Starter #15
Update

I've found that the small pipe that comes up through the floor sucks the air to the compresser/pump that pushes the air to the exhaust back box flap.
The pump is working because i got underneath the car and unplugged it. After doing this, it stopped sucking.
So to summerise, the air is not getting to the exhaust back box from the compresser/pump for some reason.
Any ideas anyone??
Is it supposed to be open, and just close when the ECU tells it to? Ive done a search on here, and people have said that it should be open most of the time.
 

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it works off vacuum not air pressure and its usually open static and its open at tickover aswell, it usually closes above tickover but opens when you rev hard and or and pull away or are gunning it..

compressor pump????

there is an electric control valve and a vacuum acumulator tank and hosework..

 

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Discussion Starter #17
Perhaps its working correctly then!
Its open on tick over. Obviously I cant see if it closes when I pull away.
The compressor seems to be working. Its sucking air from the little pipe in the boot area.
I unplugged the compressor from underneath the car, and it stopped sucking.
The flap moves too. Its not stuck.
I was kinda hoping this was causing the problem with my bad fuel consumption :confused
I dunno lol.
 

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think your barking up the wrong tree mate and your way off target...


does your car warm up to temp quickly and where is the temp gauge needle sitting?
 

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Discussion Starter #19
think your barking up the wrong tree mate and your way off target...


does your car warm up to temp quickly and where is the temp gauge needle sitting?
Temp sits half way. Warms up quite quickly. Just had the stat replaced.
The mpg needle spends most of its life under the 30mpg mark these days. Thought a broken exhaust flap might affect the fuel consumption. Now it seems the flap isnt broken.
Must be either my Vanos seals or a cam sensor affecting my mpg.
 
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