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After adding Techron to my last 12gal of gas, the issue seemed to have resolved itself again. I drove up to Watkins Glen on Friday and the engine pulled without skipping a beat. After the first session of the first day, the Fault Engine Control appeared again while returning to the paddock. I let it cool down, ran the second session fine but stumbled back to the paddock while running at slow speed. But, before the third session the car went into safe mode again and wouldn’t go full throttle any more, so we skipped the session and returned to the paddock. My instructor Ray suggested it might be the spark plugs.
After discussing the issue with Bill Rudtner, Chief Instructor and owner of South Shore Performance, he asked me how many miles are on the plugs. When I told him 30K his eyes lit up and stated that if used on the track, the plugs should be changed at 20K. Fortunately, there was a shop in town that had replacements that I ran down and picked up. First thing Sunday morning, Bill’s team of excellent techs changed the plugs; declared the coil packs in good condition and, by 10am I was back on the track again. The car drove like a charm for 4 session and all the way home with not a single mention of the issue that plagued it all month.
Wonderful ending to a great day with great people and great support!
As it happens, one week after the four and a half hour drive from Watkins Glen with no issues, engine running fine... When I started it up at lunchtime, the rough idle and FEC came up again and the car stalled. I was able to drive for the rest of the day with the rough idle, and on route to Bill Rudtner’s South Shore Performance.
He took it in; ran the codes (same as above) and swapped the VarioCam Lift Valve Solenoid from the bank 1 to bank 2. Now the codes indicated misfires on bank 2. Apparently, the solenoid will intermittently fail (stick) in the open position require for the high cam (open throttle).
My understanding is the exhaust valves have two parts. The low part (when the engine is running at low throttle) and the high part. The solenoid is activated by the ECU when the throttle is opened. It opens the engine oil to pressurize the VarioCam lift that pushes the high cam into service. When the throttle is reduced, the solenoid is deactivated and a spring closes the oil valve. When the solenoid begins to fail it intermittently sticks open until it terminally fails. This explains why the engine pulls so strong under acceleration, but sucks at idling.
With all the sensors on this motor, you’d think there would be one that monitors this solenoid’s performance. Because ther is no direct monitor, it can be swapped during diagnosis and start working again leading the tech to look else ware or, declare the system functioning normal. Anyway, the cost of the solenoid was $175 but, labor cost me double. Once for the swap and again for the replacement of the new valve. Fortunately, the valve was in the rear of the car and didn’t require removal. So far, so good.
8/2/16- After dinner, the wife and I decided to go on I leisurely drive to the harbor when I noticed a slight hesitation upon startup. Going over bumpy Old Country Rd felt some stumbling with the engine. At a stoplight, the RPMs went south and almost stalled when taking off. One mile later got yellow "PSM Disabled OK to Drive". One more mile later got yellow "Auto Start/Stop Disabled OK to Drive". Then got yellow "Fault Engine Control OK to Drive" but the engine stumbled. Pulled off, shut down, restart saw all 3 messages again. On the way back home got barely enough power to get up the hill. I locked and unlocked the doors 3 times, power cycled battery and restarted no bad engine noise and only one message, "Fault Engine Control".
8/4/16- The car drove fine on my way to the indie porsche shop and they discovered the following codes: DME: P0172 B1 RICH, P301 MISFIRE 1, P0302 MISFIIRE 2,PO303 MISFIRE 3, P0300 TOTAL, 00418 PSM CONTROL UNIT. PDK: P199A IMPLAUSIBLE ENGINE TORQUE. PDK SELECTOR: 1802 SHIFT POSITION GATEWAY, 000401 CURRNT DISTRIBUTOR TERMINAL 30 RESET INSTRUTMENT: 00A008 PSM FAILURE. FRONT: 881202 KEY BATTERY FLAT. Nothing indicated a specific mechanical or sensor/system malfunction. They reset and cleared all codes, messages, tested alternator was charging at 14.2V. The car drove normally. Diagnosis: Sitting in the garage for 2 weeks brought the 4 year old battery to the threshold of acceptable voltage causing the sub-control computers to trip off the Fault Engine message.
8/5/16- I replaced the battery with a new Bosch Platinum and the test drive drove fine.
8/6/16- Drove 2.5 hours to Limerock for DE with PCA CVR running like a champ. At the track, it drove fine all morning. Then, after the 2nd session, driving in the paddock, the engine didn't idle properly and showed the same messages as on 8/2/16.
Spencer *** (great guy) of Speedsport in Danbury, CT, read the codes that matched the ones reported on 8/4/16 and concurred there were no causes listed for the errors. He cleared the messages and the car ran fine in the 3rd session but stumbled during return to the paddock and showed the same messages. I ran the 4th session without removing the messages and the car ran fine until the road back to the paddock when it stumbled again at low RPMs. Hoping I can stumble my way home by keeping the RPMs up, I filled the now empty tank with Shell 93. To my amazement, and the car ran perfectly fine at low RPMs all the way home.
Since then I’ve driven it perfectly fine for the past 4 days with no issue or messages (the ones that appeared at the track must have cycled out). Could I have had water in the gas the week before the DE that caused the misfires only at low speeds? Could it have needed two tanks to clear itself? Have any 991 owners had a similar experience or thoughts as to what might be going on here.
Thanks for your thoughts_Steve
hi there.. what happen to the
code 881202 key battery flat ?
i can't fix this issue and no any related post around..
help would be appreciated.
thanks
I've seen some weird PSM and autostart stop warning issues with a low battery.. These cars chew through batteries like no other cars I've owned... and some weird stalls at idle with an iffy crankshaft position sensor. Neither left any codes. Neither happened more than once every year at most... I guess if there are no codes nothing happened ;-) I'd like to redo the crankshaft sensor (i hear porsche has a shim for it now esp for manual cars) but i cannot find any info here or elsewhere about how-to or where to get that shim...
As it happens, one week after the four and a half hour drive from Watkins Glen with no issues, engine running fine... When I started it up at lunchtime, the rough idle and FEC came up again and the car stalled. I was able to drive for the rest of the day with the rough idle, and on route to Bill Rudtner’s South Shore Performance.
He took it in; ran the codes (same as above) and swapped the VarioCam Lift Valve Solenoid from the bank 1 to bank 2. Now the codes indicated misfires on bank 2. Apparently, the solenoid will intermittently fail (stick) in the open position require for the high cam (open throttle).
My understanding is the exhaust valves have two parts. The low part (when the engine is running at low throttle) and the high part. The solenoid is activated by the ECU when the throttle is opened. It opens the engine oil to pressurize the VarioCam lift that pushes the high cam into service. When the throttle is reduced, the solenoid is deactivated and a spring closes the oil valve. When the solenoid begins to fail it intermittently sticks open until it terminally fails. This explains why the engine pulls so strong under acceleration, but sucks at idling.
With all the sensors on this motor, you’d think there would be one that monitors this solenoid’s performance. Because ther is no direct monitor, it can be swapped during diagnosis and start working again leading the tech to look else ware or, declare the system functioning normal. Anyway, the cost of the solenoid was $175 but, labor cost me double. Once for the swap and again for the replacement of the new valve. Fortunately, the valve was in the rear of the car and didn’t require removal. So far, so good.
_Steve
I just had the exact same issue on my 2015 C2! The three faults you got on your first event were the same and I thought that's where this was going. Luckily mine was in it's last week of warranty and was covered by the dealer. I am glad to see an Indy shop was able to diagnose and repair it. My dealer quoted the part at $221 and 3 hours of labor.🙄
It happened to me last night! I have a 2013 C4S with 67,000 on the clock. Last night, went for a food run, and within two blocks of leaving the house, my car exhibited the same medley of errors as you and others have reported. I shut off and restarted the car. Like magic, everything returned to normal, albeit with the error lights and message in the instrument panel. Neverles, not wanting to temp fate, I carefully return home to have a look with the PIWIS. Dashboard looked like Christmas time! As soon as I got home, I hooked up my PIWIS and saw all the error codes (see attachments). I reset all errors and now the car drives perfectly!
This make me VERY nervous to take the car on an extended journey unless I can pinpoint the source of the problem! I'll report any additional finding after speaking with the dealer.
08-29-2016, 06:31 PM
-Third and Fourth Track Days
