MISFIRE CODE GT3s
12-01-2015, 09:17 PM
#16
Nordschleife Master
Ok,so it seems in most cases the damage was discovered in the cylinder head. I'm still having a hard time thinking that the damage had happened due to lack of lubrication. There's a possibility the stresses are so high on the rotating components at high RPM,that things just break in some engines. That would support the theory of why isn't Porsche concerned with a design issue,such as lack of lubrication.
12-01-2015, 09:25 PM
#17
Rennlist Member
Does anyone have any reliable feedback as to why does Porsche need to replace a whole engine because of misfires?
I have read different opinions and some are pointing to an oiling issue at high RPM. What does that mean exactly? They have found some scored cams,but my theory on that was that it's happening on cold starts. I thought then that the scoring that has happened on cold starts manifest at higher RPMs,due to the increased stresses put on the cams by the Variocam system,which demands high lift and high duration. I just can't comprehend cam scoring at high RPM due to lack of oiling. Please do some research on this : the oil volume inside the cylinder head at high RPM must be tremendous on an engine with 5 oil pumps,out of which one is on demand computer controlled and a dry sump that is providing oil volume to compensate high lateral Gs. There is no way a good engineering manufacturer could've messed that up!
Another issue I see with cam scoring due to lack of oiling at high RPMs is that it's so much cylinder dependent. In other words,I have read in most cases of single cylinder misfires and not several.
I would think there's s better chance of scoring inside the cylinder bores,judging by the shape of those plugs seen on Dr Juperman's car. This area is where I suspect Porsche is having problems with the manufacturer of these plugs. I suspect they are not built strong enough to withstand the heat generated by a high revving direct injection engine. The injectors are subjected to the same " treatment ",since they are now squirting directly into the combustion chamber. Coils are also subjected to higher stress,but they are not as vital in terms of potentially causing physical damage to the engine.
I have read different opinions and some are pointing to an oiling issue at high RPM. What does that mean exactly? They have found some scored cams,but my theory on that was that it's happening on cold starts. I thought then that the scoring that has happened on cold starts manifest at higher RPMs,due to the increased stresses put on the cams by the Variocam system,which demands high lift and high duration. I just can't comprehend cam scoring at high RPM due to lack of oiling. Please do some research on this : the oil volume inside the cylinder head at high RPM must be tremendous on an engine with 5 oil pumps,out of which one is on demand computer controlled and a dry sump that is providing oil volume to compensate high lateral Gs. There is no way a good engineering manufacturer could've messed that up!
Another issue I see with cam scoring due to lack of oiling at high RPMs is that it's so much cylinder dependent. In other words,I have read in most cases of single cylinder misfires and not several.
I would think there's s better chance of scoring inside the cylinder bores,judging by the shape of those plugs seen on Dr Juperman's car. This area is where I suspect Porsche is having problems with the manufacturer of these plugs. I suspect they are not built strong enough to withstand the heat generated by a high revving direct injection engine. The injectors are subjected to the same " treatment ",since they are now squirting directly into the combustion chamber. Coils are also subjected to higher stress,but they are not as vital in terms of potentially causing physical damage to the engine.
12-01-2015, 09:40 PM
#18
Rennlist Member
Does beg the question though doesnt it? PAG have been aware of this issue now for just over 12 months (earliest reported misfire code I know Nov 2014). They stopped producing GT3 last week so they have been happily churning these out and at least as far as Im aware with no design revisions....
12-01-2015, 09:45 PM
#19
Race Director
2014 GT3 delivered January 2014. 1000 miles on the first engine and 4800 on the second; installed June of 2014.
Followed a modified factory break-in; under 4500 rpm for the first 500 miles, under 5500 from 500-1000 miles, 6500 from 1000-1500 miles, full revs occasionally after that but no track events until after first oil change on the 2nd engine at 2000 miles. Have done about a dozen autocrosses almost exclusively in auto mode. Street driving is almost exclusively manual mode.
Car smokes occasionally on start up; it's less likely to happen the longer it sits between drives. Oil usage is nil; I just did my yearly change and added no oil since the last one 2800 miles ago. Neither engine has ever thrown a code. Car is not included in the current coil/plug recall.
Followed a modified factory break-in; under 4500 rpm for the first 500 miles, under 5500 from 500-1000 miles, 6500 from 1000-1500 miles, full revs occasionally after that but no track events until after first oil change on the 2nd engine at 2000 miles. Have done about a dozen autocrosses almost exclusively in auto mode. Street driving is almost exclusively manual mode.
Car smokes occasionally on start up; it's less likely to happen the longer it sits between drives. Oil usage is nil; I just did my yearly change and added no oil since the last one 2800 miles ago. Neither engine has ever thrown a code. Car is not included in the current coil/plug recall.
12-01-2015, 10:08 PM
#21
Three Wheelin'
Does beg the question though doesnt it? PAG have been aware of this issue now for just over 12 months (earliest reported misfire code I know Nov 2014). They stopped producing GT3 last week so they have been happily churning these out and at least as far as Im aware with no design revisions....
12-01-2015, 10:16 PM
#22
Three Wheelin'
Thread Starter
This seems like mafia stuff!??!?! If an item under warranty has failure, how can they force one to sign something like this? Now, if it happens out of warranty, then I could see them holding the power, and hence, one would likely sign such document. An easy way around it.......somehow a close friend finds out, and discloses to the enthusiast community.
12-01-2015, 10:20 PM
#23
The bigger part of it is probably not the non-disclosure but I'm sure it's a litigation release as well.
This issue applies to all 9A1, spent 3 days at the track troubleshooting the issue with my 3.8L Cayman early in the year. The engine was purchased off Porsche in Oct 2014 from memory. Happy to give some details of our troubleshooting/testing if its helpful to others. But there is no way I would just switch the car off to clear limp mode and keep pushing it on the track.
This issue applies to all 9A1, spent 3 days at the track troubleshooting the issue with my 3.8L Cayman early in the year. The engine was purchased off Porsche in Oct 2014 from memory. Happy to give some details of our troubleshooting/testing if its helpful to others. But there is no way I would just switch the car off to clear limp mode and keep pushing it on the track.
12-01-2015, 10:26 PM
#24
Three Wheelin'
Thread Starter
Here is my profile. I'm not under non-disclosure yet! 10k miles, 4k track miles (~ 28 track days). The car has been driven hard on the track - nearly all advanced group sessions. Car is MY2015 delivery in Dec 2014. Auto-Shift during track days so plenty of 9k revs. I had an issue with the transmission skipping gears earlier in the year which never reoccured after a restart, but no engine issues until my incident on Sunday. As I noted in my limp mode post, my issue was with cylinders 1 and 4. The other person who I talked to at the track who had a similar issue only had the problem in one cylinder. His engine was replaced after a several week diagnostic in which dealer replaced coil pack and fuel injectors with no resolution, followed by discovery of damaged rockers. I did the full 2k break in and have changed oil more frequently than required in the track maintenance manual. The dealer resolution to my issue is pending.
Rich,
So with the guy you know of that had his replaced, did Porsche just treat this like any normal warranty repair? No concern from PCNA of the guy's loss of use? How long is considered normal for an engine replacement? Lemon law could come into play here. Also, Interesting to see the flow chart of Porsche's guesses, and whether or not anyone here could link their train of thought.
1. Coil Pack, Spark plugs (and likely ECU flash for mid rpm oil pressure)
2.Fuel Injectors
3.Damaged rockers (and sometimes scored cam lobes?)
The more info the better.......thanks for your update RM21
12-01-2015, 10:28 PM
#25
Nordschleife Master
But,I'm sure one of these damaged engines ended up with one of the experienced Porsche technicians at some dealership. If you have seen flat 6s apart many times and have seen damaged engines in the past,you will have a pretty good idea of what's happening. So perhaps that non disclosure agreement signed by customers applies to Porsche technicians as well...?
12-01-2015, 10:35 PM
#26
RL Community Team
Rennlist Member
Rennlist Member
Maybe someone should set up a Google Sheets to collect everyone's info in a user-friendly digestible format.
I'm happy to do it, but I suspect there are those here who are more familiar and capable with the info and issues than I.
I'm happy to do it, but I suspect there are those here who are more familiar and capable with the info and issues than I.
12-01-2015, 11:50 PM
#27
Race Director
FWIW, when I received compensation for my 2014 replaced engine, the only document I had to sign was one which said that I gave up the right to pursue legal action against Porsche for the particular fault which caused the recall. I retained my rights for any action related to other problems and did not have to sign a NDA.
12-01-2015, 11:55 PM
#28
I just picked up a GT3 two weeks ago thinking they had this engine issue behind them and this would be a bullet proof car like my GT2. This is a mess and really frustrating to hear about more motor issues.
12-02-2015, 12:16 AM
#29
Three Wheelin'
A question for those that have the proper knowledge: the RS engine had at least the crank manufactured to a different spec and RPMs reduced to 8800, any connection to these
issues? I would love to hear views.
issues? I would love to hear views.
12-02-2015, 12:30 AM
#30
Rennlist Member
Reduced RPM. Possibly. With a larger piston the same forces apply at 8600rpm as they do at 9000 rpm for the base GT3 hence they chose to reduce the piston speed (8600 in gears 3-7 manual and all gears SportAuto). This was more likely a longevity thing after the GT3 rod bolt fiasco. AP is on record in an interview before release of RS saying they could have gone to 9000 but saw no point as the engine is well beyond peak power. However I have it 100% first hand the RS was originally designed as a 9000 rpm engine, and the revision was made as late as Nov 2014 and after the marketing collateral had been created.
I have not seen the detailed workshop manual for the RS or the PET (these Should exist by now but to the best of my knowledge I have not seen any posts with links which actually makes me double curious?
Removing camshaft & Rod changes (required for different displacement etc) The only other area mentioned in AP interviews was "oiling". We have little information on this other than a recent TSB for plugs/leads which claims the GT3 ECU will be flashed with "new software giving it the same mid range oiling pressure as the 991 GT3RS". To me this would suggest the primary change in the 4.0L was possibly oiling pressure in this rpm range and this may go some way to alleviating the issues we have seen on the 3.8L.
Id like to point out nothing is new here particularly. Infact I had expected by now if the issue was endemic we would have heard much more but yet we have guys like Maniflod and orthoJoe put 3000-6000 track miles on these cars yet with no issues (I think in Europe a few who have done much more).
There have been half a dozen threads on this over the last 6 months and to date only 7-8 examples I am aware of. Im not saying it isnt an issue but I dont think its time to freak out...
Last edited by Macca; 12-02-2015 at 03:09 AM.