PSE failed

[Ringmaster999]

34 minutes ago, rowbos said:

Don't press the button when she is in the car...😃

Exactly why I went the PSE route. Best of both worlds 👍😂

[alank]

when the engine is first started from cold it seems loud, then revs die down to a quiet tickover. Does the PSE come on from start then go to off when engine settles down to tickover, or is it just loud because the engine is revving faster. (Start up map)

Am i correct in saying that pushing the button causes the valves to open using  engine vacuum, and so the default for the PSE is off, if a failure due to no vacuum or similar occurs. Just wondered.  ( I have it and love it, ha ha ) 

[Patt]

PSE on at start up - seem to recall something to do with warming up the cats ???

They tend to stick in the open position and struggle to close when dirty/failing.

[daz05]

Valves are open with no vacuum and will stay open until the cold start routine is complete and then close again. Then when you press the button it cuts the vacuum and they should open again.

 

[alank]

ok, cheers, so opposite to what i said. So I wake the neighbours, PSE on or off at start up, def worth having !!!

[Carmine]

Perhaps it depends on the car but on my GTS if PSE is switched off the car makes a loud bark at startup and then quietens down once there’s vacuum to pull the valves closed.

The extra noise during warmup may be the secondary air injection doing its thing helping to warm up the cats faster.

[Stuart21UK]

mines louder on startup, car warms up then it quietens (until I push the on button  )

[Afrikaner]

My 2016 S does the same. I kind of like it on start up then its cools down on tick over.............bliss

[Greenman]

I tend to find using terms on/off  open/closed are ambiguous when talking about this.  I tend to use loud/quiet as it’s then obvious what you mean. (And how loud and quiet relates to open and closed would depend on the design.)

in Porsche PSE case on the Boxster:

Engine off defaults to LOUD position where springs OPEN the bypass valves, so the PSE is in ON position.

When you start up the valves stay in loud mode for 10-20 seconds and the cars control unit tries to warm up the cats as quickly as possible to reduce emissions.

When the car idle returns to normal a switch on the engine (see Daz’s video where he changes this due to an issue) diverts engine vacuum down some tubes to the exhaust when they use two actuators to Close the bypass valves and make the exhaust Quiet.

When you press the PSE button (On) the vacuum is released and springs Open the valves making the exhaust Loud.

There is some talk about the car itself deciding to turn the car into Quiet mode at certain speeds even when the switch is in Loud mode.  I’m not sure if this is implemented on the Boxsters, I certainly can hear no sign of it, so maybe it’s just a 911 thing?

Edited May 6, 2021 by Greenman

[Greenman]

You can easily see the actuators under the corners of the back bumper.  It’s worth checking every now and again that the valves are moving.  You can push the actuator shafts with your hand and should be able to move them and they should spring back. When in  Loud/Open/At rest/On mode there should be about 2.5 inches  of shaft visible at the actuator,  when Quiet/Closed/Off  there is around 1/2 an inch visible. Again check Dazs video for example.

Edited May 6, 2021 by Greenman

[Menoporsche]

6 hours ago, Greenman said:

Engine off defaults to LOUD position where springs OPEN the bypass valves, so the PSE is in ON position.

When you start up the valves stay in loud mode for 10-20 seconds and the cars control unit tries to warm up the cats as quickly as possible to reduce emissions.

Remembering that when you say loud position, in this context it is 20 seconds of idling, so really not loud in practice.