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mose121

2010 911 C4S - Intake Valve Lift Faults Cyls. 1-6

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So I've got a good one here. I have a 2010 997.2 C4S that is tracked regularly. When tracking the car and the engine is good and hot, the car falls flat on its face and will barely accelerate at wide open throttle above 4,500-5,000 RPM's. Sometimes if you stay at WOT it will hesitate for a few seconds then starts to accelerate but still not like it normally would. Sometimes you can let on/off the pedal a few times and get some acceleration back and other times it does nothing. No warning lights have ever come on. Towards the end of the summer there were valve lift duration/response faults that led us to believe the solenoids were failing but the very next track day it was obvious there was no change after replacing them. Now the car is setting intake valve lift faults for all 6 cylinders, P1352, P1354, P1356, P1353, P1355, & P1351. The fault data in the VAL also shows that this issue is only present with higher engine temps. Due to the nature of the fault it's very difficult to duplicate on public roads because the engine has to be hot and you need lots of open road to run up to redline in 3rd, 4th, 5th gear without attracting attention from law enforcement. I'm getting a little nervous that the engine is on it's last legs and has a more serious internal mechanical problem that initially anticipated. The car has just under 90k on it but it has only been tracked for the last 5k miles. Prior to that it was a daily driver and maintained above and beyond Porsche's recommended service schedule. Any ideas on where to start? Keeping my fingers crossed!!!

 

Also have this posted here... http://rennlist.com/forums/997-forum/974187-2010-911-c4s-intake-valve-lift-faults-cyls-1-6-a.html#post13940596

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Starting to get some time to get back on the car.  We pulled the IPD plenum off to check for the infamous flap failure and everything checked out fine.  Decided to take an oil sample and send it off to Blackstone Labs.  The sample has just under 1,000 hard miles.  Hoping that we can get some information that will confirm or deny one of our theories that we may have bearing wear causing a slight loss of oil pressure once hot, ultimately effecting variable intake valve lift.  Worth a short anyways.  I'll post the results in a few days.  

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Oil analysis came back with high led and iron levels which may confirm our bearing wear suspicions.  Still going to check everything else before we crack it open but I'm not very optimistic.  The sample had 19 times the universal average for Lead and the Iron levels were almost at the average with just 1/4 of the miles the averages are based on.  The Iron levels may be explained by how the car is used but I don't see much else that would be causing the elevated Lead levels. 

 

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