stevecolletti

I'm not sure how common this is, but given how long it took to resolve, I thought I'd pass this info along to the forum.

From delivery, my 2012 Cayman R (6-speed manual and Sport Chrono), I have been having problems with the engine responding to throttle.
I thought that the problem was intermittent, but now that the car is (finally) working correctly, I know that the throttle was never working right, and that, intermittently, it would get very bad.

Intermittently:
The engine would respond as if the throttle was suddenly closed, then after a second or more it would start to accelerate. This happened most frequently on throttle tip-in, was worst at low rpm (from idle), but could also occur during throttle tip-in even while cruising at speed on a level freeway. Occasionally (on a level freeway and under constant throttle/speed), my car would go through a surging effect - on-off-on-off - that you could feel in the car as slight g changes.

All the time (prior to resolution):
The eGas throttle response was terrible. I could floor the car, remove my foot from the pedal, wait a tenth of a second or so, then the engine would rev to around 4000 RPM. The engine idled somewhat rough (RPM on the tach looked steady), had very weak torque off the line and at low RPM and suffered frequent stalls, with difficulty overcoming the drive-off assist.

Impressions:
It felt very similar to a fuel cut-off due to traction/stability control - throttle dies for about 1 1/2 seconds, then it takes off.

Things tried:
Traction/stability control - setting made no difference; weather and traction independent.
Sport mode - setting made no difference.
Fuel, 100-octane - made no difference.
Activating the cruise control (bypassing the pedal throttle sender) once the surging started - made no difference.
No blinking PSM light.

In fact, over the course of 2880 miles, nothing made a difference, nothing made it repeatable.

After 3 trips (with 3+ weeks stay) at my local dealer (McKenna), I decided to try Rusnak in Pasadena.

Brian Lewey, the Service Manager, brought their Shop Foreman out to speak to me. While standing in the service drive.... as I started to describe the various symptoms, he stopped me and gave me a list of some other symptoms that I'd encountered. He said that he believed it was probably a Brake Pedal Switch. He told me that they'd had a Spyder in some months ago, and after spending 2-3 weeks diagnosing and tracing the problem back, they'd found a 'flaky' brake pedal switch.

They replaced the switch... a $17 part - Brake Pedal Switch (PN 996-613-113-02)

The car now drives completely differently. It idles smoother, takes throttle linearly, is more responsive, has torque off the line, and no longer has the 'huge' eGas delay (it's still there, but it's better than the eGas throttle delay that came on my 2008 RS) - it now falls into the 'it can be improved', rather than 'this will end up killing me' category. According to the computer, it's even getting better mileage - while being driven harder. Also, (while I still hate the drive-off assist), it is now easy to pull into my garage.

In short, I feel the difference everywhere.

Apparently, if the switch signals that the brake pedal is being pushed, it kills throttle. Heal/toe downshifting always worked, so the interaction must be more complex than this.

Mine was the 3rd car they've had to replace this part in (2 Spyders and an R).

Too much of this stuff talks to (and worse, trusts) each other.

I hope this helps someone else not go through what I did.

Macster

Very interesting. Thanks for the update!

Sincerely,

Macster.

good hands

Thanks for posting. This is what makes Rennlist so valuable.

Z356

Thanks Steve. It would be interesting to see if anyone in our forum has experienced a similar issue with their Spyder or Cayman R...or any other newer model in Porsche's line. I don't believe I have that problem with my '12 Spyder but I will start paying more attention to any 'throttle issue' as I put more miles on my car (less than 800 to date).

Saludos, z356 (Carmel)

Marine Blue

I believe there is a guy in the UK with very similar issues on his Cayman R. Do you mind if I cut and paste your post on another forum (Planet 9) or maybe you can post there? I would post a link on the other forum but I don't believe the forum rules allow it.

stevecolletti

Please, feel free to forward or repost to anyone/anywhere.
I'm not on Planet 9 or 6speed.
Thanks!

Marine Blue

Thank you Steve, this will probably save a few people some frustration.

aussie jimmy

thanks for posting, steve.
glad you resolved the issue; it must be a weight off your shoulders now!
you can now enjoy the car without any reservations.

stevecolletti

I'll say! and thanks.

I've stalled that car pulling into my garage more in that 3 months/2880 miles than I've stalled all the other cars I've driven in my life, combined - at least once I'd learned how to drive a manual.

It really impacted handling, too. As neutral as the R is, I could never push it that too close to any limits because I never knew how the throttle would respond... would it die and I'd get instant understeer, respond immediately and slip into oversteer or do what I wanted and allow to ride that edge?

Day and night difference. Though, it took me nearly 50 miles of driving to unlearn all the bad habits I'd developed trying to drive around the issue.

Macster

I too seem to recall someone posted -- Planet 9 sounds about right) a complaint about a hesitation at 2K or 3K rpms and I was thinking this could apply to this owner's problem.

Sincerely,

Macster.

orthojoe

Interesting read, and good to know. Thanks for posting, steve! I remember the thread in planet 9 regarding this issue. Hopefully this will help the poor guy. I wonder what it is with these switches. I've had my clutch switch replaced, which is a common problem on 911s as well. The car would intermittently not start and the 'depress clutch pedal' light would turn on even though it was pressed down.

stevecolletti

Not a problem. As 'good hands' said, this is why these forums are so valuable.

I've gotten the 'depress clutch pedal' message twice in the time I've owned the car. It's always started the second try... just flaky enough to make me uncomfortable.

As for the brake switch, with a $17 cost, at least trial & error replacement is a cheap diagnostic.

orthojoe

Yeah, my friend was stranded in his 4S and had to get towed after that clutch switch failed. I was almost stranded once. If the message starts getting more frequent like mine did, get it replaced

khooni

Interesting. I don't have the same problem in my spyder. Will pay attention to the CR when I get mine in a few weeks.

nkhalidi

Glad to hear the minor part replacement fixed your issue. I've had no similar characteristics with my manual-trans R at 3800 miles, but now I know how to address it if the problem arises.