MezgerFIN

Hi all,

I have 2009 GT3 with a somewhat odd problem with my front suspension.

Today as I pushed the PASM button my shocks stiffen up as they should. However, as I switched back to PASM normal mode the front of my car started to drop height. I first noticed this as my front splitter scratched ground on a bump, then the steering wheel started to send unusual feedback... As I stopped to check the situation my front suspension had dropped so low that I could not turn the wheels for more than 0.5 lock. The wheels were very deep in the wheel arches and front splitter was less than 2 inches of the ground. I then switched PASM back ON as I thought I'll try to see if I can drive the car closer to Porsche service. After few minutes of driving (with PASM on) the car started feeling normal again. I stopped and checked and the nose was back up to normal level with around 5 inches between splitter and ground.

Does anyone have idea how this can happen? It musth be that PASM somehow fails and suspension goes so soft that car drops. Then PASM back on it restiffens the car and raises it back up.

Any help/ideas greatly appreciated!

audipwr1

Do you have front axle lift?

Pasm alone wouldn't change ride height - car is on springs

sin911

First of all, there is no 2009 GT3's made. Is yours a Gen 1 or Gen 2 car? On Gen 2 cars, there is a front lift option, on Gen 1 it was not available.

Second, the front of a GT3 should not be 5 inches off the ground anyways. So there seems to be something wrong here. Did you press the front lift button instead of the shocks?

The front lip can scrape on bumps, that is normal for a GT3. Ask me how I know lol!

With or without the front lift engaged your steering capacity should be the same. Can you take a picture of the button you pressed? So we can be sure.

MezgerFIN

The car is Gen2 997 GT3. Here in Europe the car was launched with model year 2009. It does not have front axle lift system. The button I'm pressing is the PASM button (with the picture of shock absorber) on the left side of the SPORT button. And as I press it the dashboard acknowledges PASM has been switched to sport mode and the suspension stiffens up, just as it should. At some point after this the front of the car starts to lose ride height (I dont know whether its after I switch PASM back to normal but I suspect its at this point). This has happened just twice so I dont know exactly how long it takes for the nose to drop down.

The car rides fairly low even normally and scrapes into bumps etc. but when the car drops its so low that the wheels dont turn and you cannot drive it.

I've attached two images to illustrate the normal ride height and the ride height when the suspension drops. And again, the car lifts itself up which is very bizarre.

audipwr1

You have a broken spring or spring perch that is loose

Steve W

Take the sway bar end links off the full stiff position.

Bernie930

What Steve said, or blown strut. Seen it a couple times before

sin911

That does seem very odd Off to a shop you go...

MezgerFIN

The springs and the springhat look ok, nothing is loose or broken. And if there would be an issue I cant see how the car could raise again to its ride height.

I'm no technical expert but how can sway bar end links have anything to do with the ride height? And how would stiffer suspension through activating PASM Sport mode cause ride height changes through the sway bar?

My best guess for the cause of this is some sort of failure in the bypass valve of the damper which somehow allows the damper to use the bypass valve when the damper is pushed in but then when the damper tries to push back the other way, the fluids would not flow as freely. If there is some sort of issue like this then it could also explain why the car can drop height and also it could explain how the car can rise again itself (if PASM button is pressed few times again and then the bypass valve goes either to fully open or fully closed but so that it works the same both ways). However, I've not heard of anyone having an issue like this which is why I'm not too convinced about the theory. Also because both sides are dropping in a similar way it could indicate that its a failure in the electric signal that's being sent to both dampers rather than the dampers themselves.. Unless my sway bar is so stiff that if one drops they both drop just as much..

I'm sending the car to Porsche for a check and they said if its a damper failure they will replace it under the extended warranty.

Any more ideas much appreciated!

997gt3north

Since the springs are not broken, or the perches are not broken / moved (on both sides at the same time), and the car is held up by the springs and perches (not the dampeners even when off), what is left is that the dampeners are actively compressing the spring (more than the car's weight is doing) - something that technically they are designed to during rebound to control the rate or rebound but something that I have never heard of them doing actively and in a sustained manner that would actually compress and keep compressed the spring - and didn't even realize they could do. Since you said it is happening on both sides at the same time (maybe this isn't actually happening - but if true even more bizarre) - it sounds like a crazy short wiring electrical issue. If it is actually just one shock on one side, then my guess is there is an internal valve failure of some kind which then combined with an active software and electrical system used to control the dampening - you are getting this weird result.

My guess is it is one bad shock - easily fixable.

Ur20v

Could be one side and the roll bar is pulling the other down?

Spiffyjiff

i'm pretty sure youve described a different scenario - you said yours goes down slowly as opposed to dropping quickly - but thought i'd throw this out there: i've seen a funny thing happen on my car (modified suspension) and on a 2010 GT (bone stock). something with the geometry of certain suspension configurations causes the drop links to "bow out" just a little bit in the middle of compression when absorbing a bump/road surface anomaly. it's like the geometry doesnt completely work or something and the weakest parts have to give a little to facilitate full travel. well, the suspension compresses past this point, meaning the links straighten up at the bottom of travel BUT the spring/rebound is not enough to create this bow out on the way back up and so your suspension gets "locked" in a compressed position. steering wheel also feels dead or weird because tie rods may be rubbing sways. i can't describe it better than that but next time it happens to you, just for giggles turn your wheel left and right full lock. if you hear a pop and the nose pops right up, that may be what's happening.

again, prob not the issue but thought i'd throw it out there.

MONKY LONDON

I get the opposite my front rleft PASM strut when parked after a while raises up, keen to see what you find. It's almost like the car self levels its self, the ground is uneven but not enough to create such a large fender gap once parked on one side. Looks like its doing a wheelie. I know they are just struts and springs and I don't have lift either so can't understand how the height changes...

Rick GT3

I also own a 2010 GT3 with PASM/air lift system (OEM factory). My car is presenting similar problems like MezgerFIN.

In my car, factory air lift system stop working(air lift failure in the dash), however if the PASM button is pressed (SPORT mode) car suspension becomes stiffer, once is set to NORMAL ride is softer. Btw no broken spring or spring perch.

front lip spoiler clearance 3-11/16" (93.66mm)

distance from the floor to the fender lip/(wheel lip to the fender lip)
LF: 25-7/16"/( 6.65cm )
LR: 26-9/16"/( 8.6cm )
RF: 25-9/16"/( 7cm )
RR: 26-7/16"/( 8.5cm )

my question is?, if once the SPORT button is pressed and the suspension is stiffer and once is back to NORMAL; can or cannot the shocks be blown?, in my opinion should not be blown.

need to know the opinion from the experts from this web site.
Thanks.
Ricardo

MezgerFIN

Just to follow up on my side. I took the car to Porsche, they checked everything and serviced the shocks. The shocks were dead straight and worked perfectly.

As per your suggestions, I got the front anti-roll-bar loosened up and also got the camber angles put back to factory settings. The car had been set up for track driving by the previous owner so roll bar was full stiff and camber pretty aggressive.

Since this work was done I've done about 2000miles without any issues. Some of those miles were very hard driving. Since the issue only occurred a few times I cannot be 100% sure it won't happen again but at the moment it seems this suspension geometry glitch was the problem. I still can't quite understand how out of all manufacturers its Porsche who has managed to create a car that can lock its front suspension when it's set up for hard use!!