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No I do not let her idle before taking off; I'm backing out within 10 seconds. I also do not take many short drives. Even my drive to pick up milk 3 miles away takes over 30 min due to a "detour".
Some corrections on my submission that may provide some additional data points:
I tend to put in approx 8oz of oil between oil changes. I'm not sure if I fat fingered 16 or not in my submission.
This is also the first time (oil run) I added a bottle of Amsoil P.I. performance improver additive to the gas the tank before I did the oil change. This is also the first time i used their "upper cylinder lubricant" within the oil sample date (2 bottles iirc). I'm unsure if this skewed the data points...
All that being said I've been toying with the idea of getting a more up-to-date tune on her as the one that is on came with the F77 package back in 2012.
v/r
Mike
Considering you have an aftermarket tune on it, you might want to pull fuel trim data to see if the tune may be over-fueling it and that's why you're seeing excessive fuel in the oil. Is this a new development compared to previous UOA reports you have on this car or is this the first UOA you've run?
Considering you have an aftermarket tune on it, you might want to pull fuel trim data to see if the tune may be over-fueling it and that's why you're seeing excessive fuel in the oil. Is this a new development compared to previous UOA reports you have on this car or is this the first UOA you've run?
This is the first time I have seen this and also the first time I have used those additives...
Wear levels look normal, but the 1.6% fuel dilution is a problem. Should not be anything more than 0.5%. Do you do short drives by chance or let the car idle to warm up? I also see that the engine had to be topped off for oil - it's possible the fuel dilution is causing the oil consumption.
I would not be surprised if you have a bad injector or a vacuum leak somewhere in the intake. Likely the oil fill tube or an AOS vent tube if I were to guess. Smoke testing the intake and looking at fuel trims might be well advised.
If you look at Fuel Trims with PIWIS on a 997.2 what would you expect to see on a car that might have an intake problem and shows Fuel Dilution, and what would a "normal" car that shows no dilution look like?
I think the Actual Values involved are 'L010_Fuel trim mean value, bank 1' and 'L020_Fuel trim mean value, bank 2', but I don't know what 'good' and 'bad' look like. Is there any difference to be expected between DFI and earlier cars in Fuel Trim behaviour?
Last edited by Eric Buckley; 02-01-2021 at 10:39 PM.
Reason: Fix 020, DFI different?
I would be very interested in PIWIS II log files collected from other 997.2's that include 'L010_Fuel trim mean value, bank 1' and 'L020_Fuel trim mean value, bank 2' to see what they look like. The files have names like '20200620_0724_14.1.8-dataloggerprotocol.csv' and can be collected by setting up logging in PIWIS and driving around a bit. I am attaching a log that I took that includes these fields:
Time (ms),
A020_Engine speed (1/min),
A100_Vehicle speed from PSM (km/h),
D010_Pedal value (%),
L010_Fuel trim mean value bank 1 (%),
L020_Fuel trim mean value bank 2 (%),
N010_Nominal intake camshaft angle (KW),
N020_Actual intake camshaft angle bank 1 (KW),
N040_Actual intake camshaft angle bank 2 (KW)
I'd love to see some other ones. I have a Excel sheet with some VB macros that take the file format attached and turn it into something I can use another viewer to look at outside of PIWIS comfortably.
If you look at Fuel Trims with PIWIS on a 997.2 what would you expect to see on a car that might have an intake problem and shows Fuel Dilution, and what would a "normal" car that shows no dilution look like?
I think the Actual Values involved are 'L010_Fuel trim mean value, bank 1' and 'L020_Fuel trim mean value, bank 2', but I don't know what 'good' and 'bad' look like. Is there any difference to be expected between DFI and earlier cars in Fuel Trim behaviour?
As Wayne says, they should be very close to 1 and when we say very close to 1, we're talking about 1.0000. Anything below that, like even as much as 0.98 means the DME is registering a rich condition and pulling fuel to lean out the mixture. Number above 1.0000 mean the DME is sensing a lean condition and adding fuel to richen the mixture.
I have seen this elsewhere, but it seems to be for .1's. I am seeking some data that supports this (invariant Fuel Trims right at 1.00000 on a 997.2 while being driven) via PIWIS logs. The log I attached earlier shows the Fuel Trims varying between almost -6 and almost +8 and changing constantly. The car runs well and has no check engine light or any ECU codes. I expect that on a .2 variation in Fuel Trim is normal, but there is probably good/normal variation and bad/abnormal variation and I would be interested to learn more about that.
If you look at Fuel Trims with PIWIS on a 997.2 what would you expect to see on a car that might have an intake problem and shows Fuel Dilution, and what would a "normal" car that shows no dilution look like?
I think the Actual Values involved are 'L010_Fuel trim mean value, bank 1' and 'L020_Fuel trim mean value, bank 2', but I don't know what 'good' and 'bad' look like. Is there any difference to be expected between DFI and earlier cars in Fuel Trim behaviour?
A direct injected engine will have higher fuel dilution than a port injected engine. That's just the nature of the beast. A normal UOA for an M96 engine should have no more than .5% fuel dilution. I would expect a DFI car to have higher numbers.
I'm by no means an expert when it comes to fuel trim. Tony Callas was at our shop and we did a short video on the topic since these questions come up fairly often:
Wow. That is very interesting to watch, and a wonderful service to the community for you and Tony Callas to share this. I see that this is very recently released, and that there are more segments to watch on related topics. Thank you for this.
On Fuel Trim Tony is very educational. He says that 'Fuel trim mean value' is not usually what you want to look at in a Porsche. He is not so specific on exactly what DFI Fuel Trim should look like. He emphasizes looking at Idle Trim and notes that the units are different for DFI than port injection and for DFI the number (mg/stk) ranges from -3.5 to +3.5. He also talks about 'RKAT' as being Idle Fuel Trim for 'earlier' cars. I can't find the mg/stk number in PIWIS so far, but I do see a pair of RKAT values (units are mg/H). I'll have to look more at those. I have looked at some of the other Load trim values, but it is hard to know what to look for,
I'd still be very interested to see some actual PIWIS logs of Fuel Trim from real cars.
A direct injected engine will have higher fuel dilution than a port injected engine. That's just the nature of the beast. A normal UOA for an M96 engine should have no more than .5% fuel dilution. I would expect a DFI car to have higher numbers.
I'm by no means an expert when it comes to fuel trim. Tony Callas was at our shop and we did a short video on the topic since these questions come up fairly often:
Hi all,
After looking at these other reports, I am a bit worried about my numbers. Please take a look at the Aluminum and Silicone levels and please share whatever insight you may have. I did not have a scope done when I purchased the car at 39k miles.
Thanks so much for any thoughts and opinions.
Hi all,
After looking at these other reports, I am a bit worried about my numbers. Please take a look at the Aluminum and Silicone levels and please share whatever insight you may have. I did not have a scope done when I purchased the car at 39k miles.
Thanks so much for any thoughts and opinions.
Jeff
Jeff, this reports say Mobil 0W40 but your viscosity numbers show otherwise. Your car certainly did NOT have Mobil 0W40 (or any 0W40 for that matter) in it. Change the oil again in another 3-5,000 miles, to flush out more of the old stuff, and I suspect your numbers will continue to improve. What oil did you fill with?
Hi all,
After looking at these other reports, I am a bit worried about my numbers. Please take a look at the Aluminum and Silicone levels and please share whatever insight you may have. I did not have a scope done when I purchased the car at 39k miles.
Thanks so much for any thoughts and opinions.
Jeff
Aluminum and iron are both quite high for only 2,600 miles on the oil. For reference, at 4,000-5,000 miles I never see double digit metal ppm numbers on either of my 997.1 cars. I'd keep an eye on it and continue to to run the Blackstone analysis. If they stay high like this you'll need to get more invasive by pulling the sump and scoping the cylinders. Aluminum can really only come from the pistons and cylinders. Iron is usually bearings, but usually has copper accompanying it.
I also agree with LexVan that those cold and hot viscosities are much higher than M1 0w/40. What's in there looks like maybe a 10/50 or 15/50 weight oil which is too thick for these motors for both cold start flow and the variocam system.
I hate to say it, and sometimes think the worst, but it looks like this is the first oil change since you bought the car and from the viscosity numbers, the PO or dealer may have put a much heavier oil into the engine to mask a knocking sound that may have been present with the proper weight oil.
02-01-2021, 11:54 AM
