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I would boroscope through the spark plug before making a decision, maybe even replace injector #5.
Techron is a solvent cleaner, in this case sprayed directly into the combustion chamber. If the Techron helped I would continue to follow fueling issues although if you have carbon build up it could have helped there (hence the boroscope).
Doubt you have a bad lifter at this mileage.
I would boroscope through the spark plug before making a decision, maybe even replace injector #5.
Techron is a solvent cleaner, in this case sprayed directly into the combustion chamber. If the Techron helped I would continue to follow fueling issues although if you have carbon build up it could have helped there (hence the boroscope).
Doubt you have a bad lifter at this mileage.
Hmm this gives me some hope. It seemed the porsche tech was quite knowledgeable when discussing the lifter tap. I'm not an ICE expert but your points make sense. I hope i didn't waste $500 for a random diagnostics--
Sorry for the slew of questions:
- What would I be looking for assuming i bought a boroscope and took a quick peek?
- Anyway to test/isolate the fuel injector?
- Still worthwhile to look into fuel pump / regulator? Seems less likely since the replacement of the spark plug / ignition coil, for those 2 days, it ran smooth as silk. I'd imagine that wouldn't be the case if my fuel pump / regulators were damaged and more than just cylinder 5 would be triggering.
Hey folks, just closing the loop here and providing an update incase it helps others--
After a week of back and forth with Porsche of Redwood City in the bay area (would highly recommend, I worked with Greg from the service department and the service and attention to detail was impeccable. Did not attempt to sell me unnecessary things and helped to explain everything to a tee. As well as chatted with Michael, the service tech, who provided insight):
- Turns out, after another sparkplug and coil swap, which helped for about 2 days, the issue sprung up again specifically for Cylinder 5 misfiring (CEL, PSM, Start/Stop failures/lights). They were able to reproduce the issue in the shop and seems to be coming from the LIFTER/CAMSHAFT which points to an internal engine issue. There is a well defined lifter tap from cyl 5 and their guess is that it is gunked up and not opening/lifting as designed, hence, fuel additives seeming to temporarily help with the issue. Unfortunately, they would need to disassemble the engine to confirm this which would be an extensive job. At that point, it would make sense to make the swap out but at a cost of ~$9k. I called up some indies to see comparison but they pointed out some important factors: engine reassembly is a difficult job with high risk, mistakes can be catastrophic and 2 of them declined to even attempt/quote the job. Plus porsche dealership would offer a 2 year warranty on the parts itself.
Now just at an impasse with what to do:
- wholesale for a loss and just accept it
- continue to use fuel additives to see if it can help with the gunk assuming its the issue and continue driving
- repair, but i dont see myself forking over 9k. Might make more sense to move to a cayman gt4 or another 911 at that point.
Thoughts?
I'd give these guys a buzz with all the documentation you have available and see if they have ideas, they have rebuilt many 9A1 motors and I am sure are more knowledgeable about these motors than any dealership. Maybe they can point you in a better direction?
Honestly not sure what I would do first as there seems to be conflicting diagnostics.
Would still check fuel pressure under load as your misfire counters did rise on all cylinders.
Also would check leakdown and compression just to cover the bases.
With the boroscope you are looking for carbon build up and bore scoring (search for pictures).
This is definitely interesting, so please keep updating us with your results/findings.
In between my last two Porsche's, I owned an Audi S5 for short time. Those cars are notorious for the carbon build up issue, and the majority of the higher mileage cars had it. The carbon cleaning process was relatively inexpensive and resolved the majority of the multiple CEL codes that these cars would throw.
I haven't heard of too many issues with carbon build up on our DFI cars, but they are now getting into the mileage range. Good luck and keep us posted!
This is definitely interesting, so please keep updating us with your results/findings.
In between my last two Porsche's, I owned an Audi S5 for short time. Those cars are notorious for the carbon build up issue, and the majority of the higher mileage cars had it. The carbon cleaning process was relatively inexpensive and resolved the majority of the multiple CEL codes that these cars would throw.
I haven't heard of too many issues with carbon build up on our DFI cars, but they are now getting into the mileage range. Good luck and keep us posted!
Thanks Joec, I'll reach out to those folks. That's super encouraging given the indie's were quite adverse to working on the 9A1 motor. Guess it's still relatively new.
and thanks VII7, will do, good pointers.
Originally Posted by Jack F
Sorry to digress, but what year Audi?
- To add a question here, what specific carbon build up cleaning steps were taken? Seems like there are many routes and hopefully urs didnt involve disassembling the engine haha.
Thanks Joec, I'll reach out to those folks. That's super encouraging given the indie's were quite adverse to working on the 9A1 motor. Guess it's still relatively new.
and thanks VII7, will do, good pointers.
- To add a question here, what specific carbon build up cleaning steps were taken? Seems like there are many routes and hopefully urs didnt involve disassembling the engine haha.
Permanent Fault Engine Control - Possible to Drive On Yellow light (used to be intermittent, is now present even after restarting the car)
Engine will heavily shudder / vibrate (I would assume misfiring) under hard acceleration or hard turning/driving and lose significant power for anywhere from 10 seconds to 10 minutes -> this then would add the following yellow lights:
- Start/Stop deactivated
- PSM Loss
I took it to a local Indy and they ran the codes and the PSM Control Unit fault came up along with P1044 and P1433. There was also something about the PDK. The mechanic couldn't figure it out and cleared the faults. A week or so later, I started again getting the extreme misfiring and shudder after 10 min of driving. Before it would take about 20 or so minutes before it would start misfiring. I was in the process of purchasing a home and decided to sell the car to Carvana and not look more into it.
I am curious to see how this plays out for the OP. I would definitely get another opinion before shelling out $9k
Thanks Joec, I'll reach out to those folks. That's super encouraging given the indie's were quite adverse to working on the 9A1 motor. Guess it's still relatively new.
and thanks VII7, will do, good pointers.
- To add a question here, what specific carbon build up cleaning steps were taken? Seems like there are many routes and hopefully urs didnt involve disassembling the engine haha.
I mean, even with the shipping cost $800-1000. It could be worth shipping your car to one of those shops if they are confident they know the cause and can make the repair. Then you have a nice roadtrip home
I would continue with the Techron or a stronger solvent (liquimoly has a few options that are pretty strong) to see if it gets better. I would also give Jon @BGB Motorsports a ring as he is the 9a1 god (especially in the 981 chassis) to see what he suggests.
It was a 2010 S5 (B8), last of the V8's with a 6sp manual transmission. It was a great car to drive around town, but just not the same anywhere else. Plus the Audi community was just not the same as what we have here.
See the before/after pic:
if youre in socal, i highly recommend to try and contact House Automotive (Pasadena and Encino locations). Greg is the owner there and super knowledgable and helpful in diagnosing our cars. And he wont try to upsell you on anything unnecessary either. 100% honest and direct guy.
If I was you, I would lean on what jeffm is saying. Almost all modern cars will have this carbon build up, our cars are no different. This is why a lot of guys use oil separators(oil catch cans). It catches most of the oil that would normally get sucked back into the intake and causes the carbon build up. I think one of the vendors here have already created an oil separator for our cars. Anyways, call around and find out who can do the carbon cleaning. For a few hundred bucks, wouldn’t hurt to do it. The Porsche techs seemed confident something could be gummed up. Or, get a scope and check yourself, or have a shop do it.
01-26-2021, 09:16 PM
