QuickOne

Hi All - I have a ‘16 991.1 RS with ~2100 miles on it. I’m having an issue on track the last few days and not sure what’s going on. Wanted to get the view of the group here.

Basically, it seems to correspond with the 3-4 (primarily, sometimes 2-3) upshift in the PDK around 7k rpms. I’m running in PDK Sport and I drive the car pretty hard. It’s as if the car kills all power for a second, violently throwing the weight forward, before coming back to life. It’s so violent, it’s almost as if someone is hitting the brakes and it upsets the balance of the car mid-corner (scary - the wall isn’t far off..).

Not sure if it’s PDK slipping and the ECU killing power or what.

I have video that I’m trying to edit out fro my VBOX that demonstrates this. I can see in the data logs that RPM basically goes straight down when this occurs. Working on getting that sorted so I can upload it.

I pulled the codes, but there isn’t anything in the ecu that my code reader can see.

Any ideas??

QuickOne

The issue can be seen in the following video at 7 seconds and 12 seconds. Watch throttle position go to zero and all of the weight shift forward. It then immediately comes back on the first one. On the second time, I lifted when it occurred as I knew the car was hosed.

911therapy

I was having a similar power cut out issue in my GT4. I think we figured out it was bad coil packs, so we replaced coil packs and plugs. But, I havent had it back on track just yet. I cannot duplicate the issue on the street.

tstafford

All - How much data is available from the ECU of a 991 on this type of issue? Asking because I believe this would be fairly easy to diagnose in a race car (my experience is with the Radical) because the ECU read outs would show what’s going on. Feels like you could quickly eliminate some things at a minimum.

QuickOne

On the VBOX I was able to pull enough data to identify an issue (RPM, Speed, Gear change, Throttle Position, etc.), but was not able to see what was happening beyond that. The VBOX is awesome, but I definitely would like to see more data from the car. Like oil pressure, oil temp, fuel pressure. That would help diagnose the issues more.

It’s on its way to the dealer now - they flat-bedded it this morning. I’ve been in contact with the master tech, and he’s been extremely helpful. We’ll see what it needs soon.

911therapy

Keep us posted - hope its a quick easy fix for ya

WP0

Subscribed. . . my very uninformed opinion of the engine leads me to wonder if it is something with the TC/ESC. . . doesn't it cut power to the engine if an imbalance is noted by the computer?

QuickOne

Turned out to be a cam position sensor. Swapped it from one bank to the other and the fault moved sides. Two replacement sensors (with updated part numbers) and it seems to be ok. I took it out for an, um, "street run", and it seemed fine. Next track event is in August, so we'll see if it shows back up again. I haven't seen this issue on the street, only on track, so hopefully it's gone for good.

Will report back if it shows up again.

s4corrado996tt

Subscribed! Thx for sharing !

TRAKCAR

Good stuff, thanks!

shapiroeric

Great info.....thanks for sharing

wwlee

A friend directed me to this thread and sounds familiar to what I’m experiencing on my 981 cayman S pdk. The car short shifts however not violently. Curious - when this happened, were you able to drive on track 10-15 minutes at a time before the problem (re)occurred?

thanks!

QuickOne

The answer is “it depends”. If the car was starting out relatively cold, then sure, 10ish minutes before it happened. If the car was warm, it could happen on the first lap. It really depended on how hard I was pushing the car, and I’m fairly conservative with getting the car/tires up to temp before railing on it.

This one was easy to tell, though. The fault codes were accurate. So just get a code reader and pull them.

wwlee

Thank you! I think my problem is different - no fault code on pwis and no fault codes on car. Hope everything works out on yours!