28i Stutter solve but have new problem

S

sumotan

Member
Hi Gents,
Re my other post on stutter had trace it to a leaking vaccum hose now car runs fine but discover a new issue.
The exhaust valve now no longer works, it stays open all the time. Valve is not jammed still moves when pushed.
The crazy thing is with exhaust valve open, it's normally louder & growls a little, now I don't hear that sound
at all makes me wonder if somewhere else in the exhaust that has slight blockage. Any ideas Gents ?

Thanks in advance
 
Glad you fixed the stutter.
Afraid I can't help with the exhaust valve but I would be interested to know the outcome.
Mine has been like that since I got it. It hasn't had the usual modification to blank off the vacuum pipe.
I'm wondering if there is something in the engine bay that controls it or feeds the usual vacuum to it? Maybe something that got dislodged/knocked when you sorted your other issue?

Tbh I quite like the sound it makes with it open, so haven't bothered too much, but it would be nice to know the reason if you find it.
 
sumotan said:
Hi Gents,
Re my other post on stutter had trace it to a leaking vaccum hose now car runs fine but discover a new issue.
The exhaust valve now no longer works, it stays open all the time. Valve is not jammed still moves when pushed.
The crazy thing is with exhaust valve open, it's normally louder & growls a little, now I don't hear that sound
at all makes me wonder if somewhere else in the exhaust that has slight blockage. Any ideas Gents ?

Thanks in advance
Click to expand...

What makes you think the valve’s now open all the time?
Rob
 
Hi Smartbear,
Normally when I go into sport mode the exhaust notes changes to sportier sound & louder hence my question.

Thanks
 
The valve is powered by a vacuum that originates from the engine bay and is controlled via a solenoid in the boot.
I suspect seeing as yours did work and now it doesn't your problem is linked to whatever you did to fix the vacuum leak you had in the engine bay.

On mine it never worked and I couldn't find a fault (vacuum fine/solenoid fine etc) so I wired a switch into the centre console to control it manually. (thread on here about)
My fault does seem common on N20 cars. I suspect its a wiring issue from the solenoid to the ecu, the ecu itself or even a software update at some point in the cars life had unintended consequences
 
Hi Gents,
My Z4 is with electronic wastegate , basically it has a vacuum line coming from the vacuum pump & connected to a tee which is near the front of the engine cover, it is here that I found the leak, all I did was to cut a little bit of the vacuum hose & reconnected it back to the tee & stutter problem solved but now that the exhaust valve isn't functioning does add a little head scratching for me.

Cheers
 
sumotan said:
Hi Gents,
My Z4 is with electronic wastegate , basically it has a vacuum line coming from the vacuum pump & connected to a tee which is near the front of the engine cover, it is here that I found the leak, all I did was to cut a little bit of the vacuum hose & reconnected it back to the tee & stutter problem solved but now that the exhaust valve isn't functioning does add a little head scratching for me.

Cheers
Click to expand...
As with all these things where you do something then something else won't work, the first port of call is to revisit what you did. Hopefully you'll find a leak in the other part of the vacuum pipe now, or a kink maybe?
 
When my exhaust gate rattled I just unplugged the vacuum line where it met the exhaust.

Should that be causing a vacuum leak?

I have no symptoms of a engine stumble or rumble etc.
 
2009CAZ4 said:
When my exhaust gate rattled I just unplugged the vacuum line where it met the exhaust.

Should that be causing a vacuum leak?

I have no symptoms of a engine stumble or rumble etc.
Click to expand...

You can easily plug the open end of pipe to eliminate a potential leak :thumbsup:
Rob
 
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