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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Tue Oct 08, 2019 8:38 pm    Post subject: Cayenne 2009 GTS hesitation on light acceleration Reply with quote

Well, to add to my list of problems, after changing the thermostat and a new set of plugs, and fixing the vacuum leak, the hesitation is still there.
But!! If I switch off the "PSM" it runs perfect!??, runs as if in sport mode holds the gears longer but no hesitation and pulls a lot more when accelerating,

when you switch it back on the revs drop and it become sluggish and hesitates.

just wonder if it is related to the faulty signal from the front acceleration sensor?
 
  
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Sun Oct 13, 2019 9:26 pm    Post subject: Reply with quote

Now realise that psm keeps the revs above 2k , the hesitation seems to be below 2k rpm.
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2008 Lexus ISF,
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CarraraWhite
Barcelona


Joined: 06 Apr 2008
Posts: 1298
Location: England

2011 Porsche 991 Carrera

PostPosted: Mon Oct 14, 2019 11:14 am    Post subject: Reply with quote

What garage are you using ?

did they plug in the diagnostics machine
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991Turbo, dont need the S
 
  
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crash7
Hockenheim


Joined: 28 May 2011
Posts: 707



PostPosted: Mon Oct 14, 2019 11:20 am    Post subject: Reply with quote

When were the coils last changed?

Are you getting a CEL?
 
  
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Billy Bumpsteer
Spa-Francorchamps


Joined: 12 Aug 2019
Posts: 324



PostPosted: Mon Oct 14, 2019 12:37 pm    Post subject: Reply with quote

Coil packs would be my guess
 
  
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Mon Oct 14, 2019 12:40 pm    Post subject: Reply with quote

I bought an icarsoft scanner, just put a new acceleration sensor in, still hesitating, I do all my own work.
Im sure the coils have been changed at some point, it is looking like they may need changing.
 
  
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crash7
Hockenheim


Joined: 28 May 2011
Posts: 707



PostPosted: Mon Oct 14, 2019 1:37 pm    Post subject: Reply with quote

I had a similar problem on my 58 GTS.

Intermittent hesitation under light throttle, no CEL.

I lived with it and eventually the car through up a CEL, which would reset everytime you turned the car off and not come up every journey, I carried my scanner in the car and eventually caught it, codes indicated a coil fault on cylinder 2.

Changed the coil(s), problem solved.

Good luck.
 
  
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Mon Oct 14, 2019 2:03 pm    Post subject: Reply with quote

Did the bad coil look ok? I didn't see any cracks when changing the plugs, I would assume that they all are not failing. May buy one and swap it around.
 
  
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crash7
Hockenheim


Joined: 28 May 2011
Posts: 707



PostPosted: Mon Oct 14, 2019 2:28 pm    Post subject: Reply with quote

No, no visible signs of any wear or damage.

I only had a fault with one, but given they were all the same age and original to the car I replaced them all as a matter of course, however as you say it may not be necessary.
 
  
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Billy Bumpsteer
Spa-Francorchamps


Joined: 12 Aug 2019
Posts: 324



PostPosted: Mon Oct 14, 2019 2:47 pm    Post subject: Reply with quote

A Durametric will certainly pick up the faults even if it hasnt thrown a full CEL, I take it the icarsoft didnt show up anything?
 
  
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Mon Oct 14, 2019 3:42 pm    Post subject: Reply with quote

It hasn't thrown any faults, but can see a lot of variables, I guess it should be possible to see something not running as the rest. How long do they normally last?
 
  
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Billy Bumpsteer
Spa-Francorchamps


Joined: 12 Aug 2019
Posts: 324



PostPosted: Mon Oct 14, 2019 3:55 pm    Post subject: Reply with quote

They can last 10 years or 6 months. I changed all mine and 6 months later the exact symptoms you have showed again, Durametric showed cylinder 5 missing, just changed that one that time and all ok 12 months on, get it plugged into a decent machine and it will tell you the cylinder/cylinders missing
 
  
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Tue Oct 15, 2019 10:58 am    Post subject: Reply with quote

ordered a full set.
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Tue Oct 15, 2019 11:26 am    Post subject: Reply with quote

Old and new sensor
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Thu Oct 24, 2019 11:31 am    Post subject: Reply with quote

fitted the coils, it drives differently, more torque, quieter and smoother, while playing with the scanner after 10minuites or so there was a noise like the cd player loading a disk over and over, turned the head unit of but it was still going, now I think it was the throttle recalibrating its self.
it now holds the higher gears , if you accelerate slowly it will pull along in top gear, before it would not do anything then jump down 2 gears, there is still slight juddering but it doesn't feel like a misfire. will leave if for a few weeks for everything to settle down.
got all the coil packs for under £180 off eBay.

I am also wondering if the ignition module was in the water that was trapped in the bulkhead/firewall.
 
  
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deMort
Dijon


Joined: 21 Mar 2015
Posts: 7950
Location: Brighton


PostPosted: Thu Oct 24, 2019 7:55 pm    Post subject: Reply with quote

Throttle will recalibrate if needed with ign on .. it won't happen when driving and it it needs to do this find the end stops so i doubt that is an issue ... end stops being it doesn't know full open / full closed .

New coils and it drives better would indicate x1 coil was breaking down .. but is fixed .

The box adjusts to the driver .. so if you stamp on the throttle a few times while driving then it will adapt to a faster gear change .. ie instead of x1 down shift it will do x2 .

What we call granny mode .. the car thinks everything is lazy and slow and so it will perform that way .. boot it a lot / fast stamp on the throttle and it will go into sport mode in essence .

PSM fault will have an impact but on the suspension not the engine .. well to a degree .. it can feel similar though .

Drive it .. boot it and see how it goes then report back i feel .
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Wed Nov 13, 2019 12:27 pm    Post subject: Reply with quote

A few weeks now, it now feels like it did before sluggish and jerky on light acceleration, seems to be worse when raining?
will do a smoke test soon to see if there is still a vacuum leak somewhere.
but it runs well when you boot it, smooth reving , slick gear change, sounds great, unfortunately I spend 95% of my driving in the 1000-2000rpm range where the hesitation is, but only on light acceleration once up to speed its very smooth and stable.
one of the aftermarket HID's blew, so had to fit a pair of HID bulbs from a kit someone gave me, but the output was very dim and blue, so fitted some LED Beamthech units , had to order an adaptor, seem good , just as bright as the HID's before, good solid beam pattern, and no ballast hanging out of the back of the light.
but now need to get load resistors to stop the "Check low beam " warning.
you could use these for main beam as there is no switch on delay or surge?
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2009 Cayenne GTS
 
  
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MarkGolf
Imola


Joined: 13 Nov 2012
Posts: 831
Location: S.London


PostPosted: Wed Nov 13, 2019 12:45 pm    Post subject: Reply with quote

In regard to jerkiness, do you think it is definitely the engine being jerky or do you feel it through the car?
I had some jerky/pulsating feeling at 2000rpm which turned out to be having different brand of tyres on the rear. That feeling came back on the weekend and it was due to a tyre being 20 psi..

If it's engine, are any of your plugs oily?
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1991 964 Carrera
2005 997 Carrera S
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2003 Boxster 2.7
1994 Eunos Roadster S Special Turbo 270bhp!
1991 Mercedes 500SL
1979 Mercedes 280e
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Matrixxxx
Trainee


Joined: 13 Sep 2019
Posts: 76
Location: York


PostPosted: Wed Nov 13, 2019 4:26 pm    Post subject: Reply with quote

the jerkiness is from the engine when accelerating, the whole car judders very briefly, could it be engine mounts ( not the top one) ?

Plugs were all oil free.

it has had the high pressure fuel pump fitted in the past, this could also cause my issues. seems common on the Panamera.
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deMort
Dijon


Joined: 21 Mar 2015
Posts: 7950
Location: Brighton


PostPosted: Wed Nov 13, 2019 8:32 pm    Post subject: Reply with quote

Just a wild stab in the dark but possible it's a transfer case issue .. they do give similar faults ..

A garage with experience of these issues needs to drive the car to be honest .. i kinda know what it feels like but obviously i can't drive your car so just a suggestion .
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My Daughter's Crowdfunding has hit the target .

Thank you all so Very much .

She's not going until july 2020 though .



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