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Porsche Sports Exhaust Fault - PSE Troubleshooting Fix

TonyC911

Well-known member
Joined
6 Jun 2016
Messages
1,372
Hi folks,

I thought I would post this subject just in case it can benefit others.
I have a C2S Gen1 with the factory Porsche Sports Exhaust, which I bought about 3 years ago. I have always been a bit underwhelmed with the sound, but I assumed that if it was faulty, it would have been picked-up by an OPC mechanic during a major service or one of two 111 Point Warranty check, right? After all, they spotted the windscreen wipers were not OEM and presented me with £6,500 quote for work that needing doing... well errrr... no!

So I had some time on my hands recently and I started trawling the forum for ideas on how to diagnose a possible fault. I knew the system was working in part, as when pressing the switch the exhaust note did change, but I suspected that not both valves were operating. Research suggested that the manual vacuum valves can often fail and this was somewhat confirmed when I read that with the PSE switch on, exhaust gasses should exit from both of the twin tale pipes. One side was clearly not working!

Access to the vacuum valves is impossible from underneath, so I had to bite the bullet and remove the bumper, which is not too difficult after you have found all the pesky screws! This guide was very helpful - https://guides.drivediy.com/Guide/Porsche+911+997+Rear+Bumper+Removal/49

The heat shields also come off pretty easily and this gave my OCD a chance to clean them and also gives good access to clean the chrome exhaust tips!

What I discovered was a bit perplexing after I thought about it. You can just about see in the picture that the exhaust flap control arm was seized, not altogether surprising given the operating temperatures and I assumed the vacuum valve had failed, causing it to stick in the closed position. Having soaked it in oil overnight, I was able to free the mechanism and to my surprise the valve was working perfectly.

Here's what I had not realised; with the ignition off, the exhaust flaps are in the open position = PSE on. With the car started and the vacuum circuit complete, the exhaust flaps are closed = PSE off.

What is very curious is that the exhaust flap on one side had seized closed?? :dont know:

Anyway, turned out to be a pretty easy fix in the end and boy does it sound good now!! :thumbs:
 

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Top notch young man ..

There is no access to these valves so pu off is the only way .. well unless you are very bendy with very thin arms and on a ramp !

These valves can leak .. which will stop both sides from working ..

The rods can also rattle .. if your lucky you can adjust them .. but often seiezed .

Some times the grey electric valve can fail .. this can stick in either on or off .. but normally off .

I personnely think this system is one ofthe best out there .. might be beaten by some of the rather expensive aftermarket systems .. but Porsche got it pretty much spot on with this one .. IMHO !
 
I had exactly the same issue with mine when I got it and was able to free then and grease with suitable material. No problems since except when one of the vac pipes came off and that means rear panel off again. Metal sheathed pipe is very difficult to get on again as it is hard, presumably with heat and age.
Should this pipe have a clip?? I used a piece of wire when I refitted.
 
ian_alex said:
Should this pipe have a clip?? I used a piece of wire when I refitted.

Yes, it should have a small hose clamp see #9 on diagram below - part no. 999.512.361.02

That said, I noticed that the vacuum unit had been replaced on the other side of my exhaust and they failed to put a new clamp on... it would have been replaced by an OPC :roll:

Your wire fix will probably be fine for a good while.
 

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Thanks, yes, my bodge will be absolutely fine. I'm not taking the rear off for that!
Regards
 
deMort said:
Top notch young man ..

There is no access to these valves so pu off is the only way .. well unless you are very bendy with very thin arms and on a ramp !

These valves can leak .. which will stop both sides from working ..

The rods can also rattle .. if your lucky you can adjust them .. but often seiezed .

Some times the grey electric valve can fail .. this can stick in either on or off .. but normally off .

I personnely think this system is one ofthe best out there .. might be beaten by some of the rather expensive aftermarket systems .. but Porsche got it pretty much spot on with this one .. IMHO !

Ian.....just put mine back on the road today after being SORN'd for the winter. When I started her up, the first thing I normally do is switch on the PSE (off when unlit - On when lit in my 997.1 C4S)

However even though the light came on the noise level didn't change.....when I took her for a drive it sounds like the PSE is on, even though the light is switched off.
Switching it on and off while driving doesn't change the exhaust note.

Could it be stuck in the on position, and does this cause me any problems if I just leave it on all the time? Many thanks.
 
Porschekit said:
Ian.....just put mine back on the road today after being SORN'd for the winter. When I started her up, the first thing I normally do is switch on the PSE (off when unlit - On when lit in my 997.1 C4S)

However even though the light came on the noise level didn't change.....when I took her for a drive it sounds like the PSE is on, even though the light is switched off.
Switching it on and off while driving doesn't change the exhaust note.

Could it be stuck in the on position, and does this cause me any problems if I just leave it on all the time? Many thanks.

Basically, these exhausts can fail in either position, depending on the root cause. The easiest check to workout if your PSE is stuck on or off, is to start the engine as normal and then feel / observe if the exhaust gasses are exiting from either both sides of each tailpipe, or just one side. Next flick the switch and see if there is any change.

If the PSE is stuck on (as you suspect), you will have exhaust gasses exiting from both tailpipes on both sides. Hope that helps!
 
:agree:


The grey valve switches a vacuum to the PSE valves which in turn operate a diaphram which pulls the rods .

Any vacuum leak or the grey electric valve going faulty will stop the PSE from working.

When they stick it tends to be just one side .. although it can be both... bit more unusual though.

To check then you need to see if you have vacuum out of the grey valve first .. then you would check for vacuum at the valves and finally move onto they are seized or one of them is leaking .. hence a loss of vacuum .

You would also stick your head under there whilst someone operates the system to see if anything is moving .
 
Mine had a really slow actuating valve, slow to open and slow to close, this was due to a partially blocked braided vacuum hose.
 
Mine was stuck in the "on" position when i bought it.
it still is!

I like the sound it makes so see no reason fixing it to make it sound quiet.

(thanks to the OP tho` ; an interesting read)
 
A common hack is to simply remove the electrical connector on the vacuum solenoid at which point the PSE defaults to loud. This also eliminates the rev dependent control of the valve by the ECU which defaults to quiet on startup and switches to QUIET even when ON at certain revs to comply with noise regulations in some countries.
 
TonyC911 said:
Porschekit said:
Ian.....just put mine back on the road today after being SORN'd for the winter. When I started her up, the first thing I normally do is switch on the PSE (off when unlit - On when lit in my 997.1 C4S)

However even though the light came on the noise level didn't change.....when I took her for a drive it sounds like the PSE is on, even though the light is switched off.
Switching it on and off while driving doesn't change the exhaust note.

Could it be stuck in the on position, and does this cause me any problems if I just leave it on all the time? Many thanks.

Basically, these exhausts can fail in either position, depending on the root cause. The easiest check to workout if your PSE is stuck on or off, is to start the engine as normal and then feel / observe if the exhaust gasses are exiting from either both sides of each tailpipe, or just one side. Next flick the switch and see if there is any change.

If the PSE is stuck on (as you suspect), you will have exhaust gasses exiting from both tailpipes on both sides. Hope that helps!

Thanks Tony, I checked and exhaust gasses come from both pipes either side so it is definitely stuck on, which is not a problem for short journey's or when I want it on, but I would also like to have it off on long motorway runs since it does get a bit tiring....so is the fix to pull the bumper off and check the mechanism with a squirt of WD40.....if so is there a simple Youtube vid showing how to take it off?
 
Porschekit said:
Thanks Tony, I checked and exhaust gasses come from both pipes either side so it is definitely stuck on, which is not a problem for short journey's or when I want it on, but I would also like to have it off on long motorway runs since it does get a bit tiring....so is the fix to pull the bumper off and check the mechanism with a squirt of WD40.....if so is there a simple Youtube vid showing how to take it off?

Cool, now you know that the exhaust valves are stuck in the open position (default prior to starting the car = PSE on), it makes diagnosis a bit easier.

Whilst it is possible that both the actuator valves have failed (#7 on the diagram), I would have thought this is the least likely cause. I would first check that the vacuum circuit is working correctly. I would suspect either a faulty change-over valve (#12 on the diagram), or the pipe work could be perished, have a hole in or have become disconnected. Also check that the previous owner did not disconnect the power to the change-over valve, in order to have loud mode all the time! See the orange connector in the picture below.

If the vacuum circuit you can reach is all good (the pipes could have become detached from the actuator valves, although unlikely on both), then move on to checking the actuator valves by removing the bumper and heat shields. I did include a link in my original post for removal of the bumper.

Hope that helps!
 

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TonyC911 said:
Porschekit said:
Thanks Tony, I checked and exhaust gasses come from both pipes either side so it is definitely stuck on, which is not a problem for short journey's or when I want it on, but I would also like to have it off on long motorway runs since it does get a bit tiring....so is the fix to pull the bumper off and check the mechanism with a squirt of WD40.....if so is there a simple Youtube vid showing how to take it off?

Cool, now you know that the exhaust valves are stuck in the open position (default prior to starting the car = PSE on), it makes diagnosis a bit easier.

Whilst it is possible that both the actuator valves have failed (#7 on the diagram), I would have thought this is the least likely cause. I would first check that the vacuum circuit is working correctly. I would suspect either a faulty change-over valve (#12 on the diagram), or the pipe work could be perished, have a hole in or have become disconnected. Also check that the previous owner did not disconnect the power to the change-over valve, in order to have loud mode all the time! See the orange connector in the picture below.

If the vacuum circuit you can reach is all good (the pipes could have become detached from the actuator valves, although unlikely on both), then move on to checking the actuator valves by removing the bumper and heat shields. I did include a link in my original post for removal of the bumper.

Hope that helps!

Thanks again Tony, I missed that link above.....my wife says I'm like that with socks in the draw..... :grin:
So now I can make a plan to see if its a stuck mechanism or loss of vacuum etc.....which I will do once it stops raining here......look for an update around July.... :hand:
 
Hi guys, my PSE has stuck on. I have pulled the power connecter off the change over valve (grey switch) and tested it for power, I get a good 13.5 volts when switching the PSE switch from on to off. I am confident that both silencer valves haven't failed simultaneously, how can I test the grey valve to check if it is functional? If it does turn out to be a dodgy change over valve, is it easy to swap out? It looks simple enough but though it best to check.

Cheers
 

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