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My 997 went crazy!!

gsummers

New member
Joined
7 Oct 2008
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1
Hi there,
I was wondering if anyone else has had the following happen to their Porsche??
When driving down a ramp and turning right at about 5 mph to park, my Porsche steering pulled to the left and locked! Then the car started to rev and the brakes failed completely! the engine revved until the back spoiler came up and the car crashed into the wall!
I tried braking, putting the hand break on but the car did not respond!

Since the accident I have heard of 4 more 997s that this has happened to?
Has this happened to you or anyone you know??
Porsche is blaming the driver but 5 people could not all cause the exact same accident!!?? I am worried that this is quite common and could potentially cost some ones life??

G Summers
 
:eek: scary. I hope you get it sorted ok.
 
Jeez.. That sounds scary!

Has to be a PSM fault by the sound of it: When PSM is triggered it effectively takes over control of the throttle and brakes so anything you do will be irrelevant (didn't know it also did steering on a Porsche, but does your car have active steering?)

For some reason (probably the tilting effect of the ramp), I reckon it thinks you are oversteering out of control so it has turned the steering left. Then because that hasn't 'straightened' the car up, it's started to use the throttle to power the back round (and maybe the spoiler is also triggered to give more downforce?)

Actually, thinking about it, turning on a steep slope would give the yaw-rate sensor pretty much the same input as cornering at high speed :eek: But there should also be a wheel speed input into the system to stop this happening...

Sorry to go on, but I'm an engineer (ok - anorak) and like to try and diagnose these things!

I agree, 5 people having the same accident is rather too much of a co-incidence! Do you know if the circumstances were the same in each case?
 
That is weird - it is not even close to April 1...

LOJO
 
Interesting post - and good reply Wattie. Surely you can go to Porsche with this - sounds like cars are doing it all over the world.
Computers can be a nightmare - the new 747-400 with no dials, just six tv screens in the cockpit, has worked fine after a few teething problems, but Airbus still have a long way to go after all these years of making airplanes.
From just a few days ago "The Australian Transport Safety Bureau (ATSB) has pointed to a possible computer problem as a cause for yesterday's Qantas emergency. The Qantas Airbus was en route to Perth from Singapore when it descended suddenly, injuring more than 40 passengers. The flight crew received a message of an irregularity in the elevator control system. "The aircraft departed normal flight and climbed 300 feet, the aircraft did that of its own accord and then whilst the crew were doing the normal actions in response to that not normal situation the aircraft then pitched down suddenly and quite rapidly," he said. Mr Walsh says an Airbus representative is currently travelling to Australia. Forty-six people were injured, 20 seriously, including some with spinal injuries". [There is a reason we tell pax to keep their seatbelt fastened whenever they are in their seats].
Boeing computers have no history of doing this kind of thing, but Airbus ones do, so clearly it can be safe to give control to a computer but it seems Porsche, like Airbus, have a bit more work to do.
Is there some Govenrment transportation safety organisation we can report this to?
 
Second your good response Wattie. Indeed that is scary and I am surprised that there appears to be a lack of wheel speed input into the system so it might be able to tell the differences between car parking speeds and more enthusiastic speeds. 5 (or even more) people experiencing the same thing cannot be coincidence.

~ Maxie :eek:
 
:eek: :eek: :eek:

Totally shocked
 
I had a similar thing happen to me once (but with less serious consequences) when the ABS system on a Cosworth Merc wouldn't allow me stop on a very steep hill :eek: As soon as the wheels stopped turning, it released the brakes - thinking the wheels had locked! Fortunately the handbrake was good enough to hold the car, but it was a bit scary when it happened!

Similar thing really, system responding to a loss of control at speed, not realising you're doing 5 mph!
 
Sounds scary, and a little strange, how would the car pull the steering to full lock?

Do PSM interventions get logged? If so it would be interesting to see what the car 'thought' was happening.
 
anotherGT2 said:
Do PSM interventions get logged? If so it would be interesting to see what the car 'thought' was happening.

I've always thought cars would benefit from black boxes in the way that planes do.

~ Maxie
 
anotherGT2 said:
Sounds scary, and a little strange, how would the car pull the steering to full lock?

Do PSM interventions get logged? If so it would be interesting to see what the car 'thought' was happening.

I wasn't aware that it was fitted on a Porsche, but some cars do have steering servos... Any Lexus with VDIM for example... It will literally take over control of the steering with two servo motors - you can have full right lock on, but the wheels will turn to the left if the computer thinks they need to! :eek:

A very accomplished race driver I know (reputed to be one of the Stigs) nearly had a very serious accident at 150 mph in a BMW on a banked test-track... The banking confused the yaw rate sensor and it thought he was understeering, so stability control cut in to try and induce some over-steer to compensate :eek: Only quick reactions saved him from being launched off the top of the banking at a speed you don't even want to think about (especially in a road car with no roll-cage or helmet!)
 
Wattie said:
Any Lexus with VDIM for example... It will literally take over control of the steering with two servo motors - you can have full right lock on, but the wheels will turn to the left if the computer thinks they need to! :eek:

I thought by law there had to be complete mechanical assistance linking the steering wheel to the steered wheels? The above suggests in a VDIM equipped car, they're not....?

Wattie said:
A very accomplished race driver I know (reputed to be one of the Stigs)

How many are there? :?:

~ Maxie
 
Maxie Islam said:
Wattie said:
Any Lexus with VDIM for example... It will literally take over control of the steering with two servo motors - you can have full right lock on, but the wheels will turn to the left if the computer thinks they need to! :eek:

I thought by law there had to be complete mechanical assistance linking the steering wheel to the steered wheels? The above suggests in a VDIM equipped car, they're not....?

Oops - didn't word that very well did I? You are quite correct - the system does actually turn the wheel (and of course you can let some of them park themselves - hands-free!)

Maxie Islam said:
Wattie said:
A very accomplished race driver I know (reputed to be one of the Stigs)

How many are there? :?:

~ Maxie

More than one... :wink:

It's a case of who's roughly the right stature and available on the day I think! :thumb:
 

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