23 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHMAS, Code Chasing
Leading reported evidence
Clean mas
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Leading evidence: 'Clean mas' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'oxygen sensors' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check fuel pressure' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
Headed to get my car inspected so I can get the registration renewed, which was the whole reason for the urgency.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I�ve got an Enthusiast version, or I�d let you use mine (it only lets 3 VINs be used).
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I see MAF (Mass Air Flow) and MAS (Mass Airflow Sensor) used interchangeably...
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
If they differ from each other greatly, then it�s likely a bad O2 sensor.
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
When you have an idle problem or fuel mixture codes ALWAYS check the fuel trims ( TRA/RKAT) first BEFORE attempting any repair OR clearing any codes...
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
23 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
Some people have had problems with the cable and Durametric replaced it, and then it worked.
Wanted to share some issues with my 996.1, see whether I'm on the right track (newbie DIY'er, FYI).
Last month the engine stopped holding an idle - it would start and just die. Based on research, I cleaned the MAS. That sort of worked; the car died again twice but then the idle just started barely holding about 1000 RPM. Assuming the MAS was bad, I replaced it with a Walker MAS (half the price of OEM). That seemed to do the trick. It was idleing as it had before.
About two weeks later, the check engine light came on. Engine Code P1123. Again based on what I saw on this forum and elsewhere, it appears this code has a few potential causes. It could be I have a faulty MAS (after all it wasn't OEM) so I bought a new OEM one but haven't installed it yet. Instead I started with checking the fuel pressure. This is where I am now. Key on, engine off, pressure started at 36 psi. Started the engine, pressure went to 45 psi. Let it run for several minutes, and the pressure never budged from 45-46 psi. Turned it off, let the car sit for 15 mins or so, pressure came up to maybe 50 psi or so.
This doesn't seem too far off - supposed to be 48psi at idle, 55psi when off, right? It seems I'm 3psi low, and I'm not sure whether that's cause for a new fuel pump. Some had suggested replacing the fuel pressure valve first. What would y'all do?
What is a MAS? Do you mean the MAF (mass airflow) sensor on the air filter box? I know OE is expensive, but the entire engine depends on it. Only replace with a OEM Porsche MAF sensor.
Also, put a vacuum gauge on and check for vacuum leaks (or smoke test your engine to check for leaks).
P1123 - P1123 indicates an over rich condition on one cylinder bank (cylinders 1-3) that the 02 sensor and DME fuel trims cannot adjust for, usually caused by either a leaking injector or excessively high fuel pressure.
If in question, replace the fuel pressure regulator valve before digging into the fuel pump. Again, don't go cheap. Get a new one from Porsche.
When you have an idle problem or fuel mixture codes ALWAYS check the fuel trims ( TRA/RKAT) first BEFORE attempting any repair OR clearing any codes...
The codes/problem can be either rich or lean and looking at TRA/RKAT for "positive or negative values" will put you on the right path and eliminate half of the possibilities..
IE . Code P1123 can mean either "rich limit reached" OR " lean limit reached" and looking at the TRA/RKAT is the best/(almost only) way to know the difference...
Did you see the "newbie DIY'er" in my OP?
I can google it but if you can give a few sentences about what you mean by "check the fuel trims" I'd appreciate it.
You will need at the min a Durametric Tester...since your a "newby" you probably don't have one yet, but if you plan to DIY it will pay for itself in the first repair...
Here is a video where Tony explains fuel trims on Porsche very well, I hope you can wrap your head around it, it is very accurate...He rambles a lot at first but pay attention to the talk on fuel trim/TRA/RKAT when he finally gets going ...
You Tube
If you can get your hands on a generic OBD2 scan tool with �Live Data� capabilities, you can try this:
Compare the short- and long-term fuel trims for Banks 1 and 2. If they differ from each other greatly, then it�s likely a bad O2 sensor.
If both values are practically the same, then it�s unlikely to be an O2 sensor (unless they both happened to freak out at the same time�)
Be extra careful when using generic scan tools for Short/Long fuel trims and analysis and code interpretation. The generic tools don't use/display the same values as the Porsche Protocols and has confused many people and led them on Wild Goose Chases...
Yes, that�s a very valid point. My suggestion was only intended to determine the starting point of diagnostics: whether you�re looking at a fueling issue for a single bank, or both.
You have had your 996 for 9 years and you don't own a Durametric?
What do you do when the CEL comes on? (because we all know it does)
Pay the Dealer $250 to clear the code? (and throw parts at the issue?)
Do as Skip said: Get the Durametric.
You will be glad you did.
I bought one and it won't connect, durametric not much help, say it's the car. PSC Halifax says no it's not, as pwis read everything just fine. So I have a durametric that is useless to me. So I'm not especially glad... Just sayin'.
Did you follow the instructions from Durametric for the download, including the USB drivers, and installation? Some people have had problems with the cable and Durametric replaced it, and then it worked. It also sometimes depends on the operating system you are running, and the laptop. Older operating systems the software works very well. Newer operating systems not so much. If you have a spare laptop, try running it with Windows XP.
Did you buy the Durametric new? Is it the Enthusiast version or Pro? I�ve got an Enthusiast version, or I�d let you use mine (it only lets 3 VINs be used). If you�re up to Halifax any evenings next week, I�d be glad to try to help out. I�m no expert with Durametric but have used mine a number of times. Feel free to PM or email me. Joe
It's new, the enthusiast version.
Too kind! Yeah, my brother and his wife are visiting from TO and I'm going to ride to Halifax with them on the 12th, and get my car. That's a Friday. Would love to hang and meet you and your car. My durametric is in my car, maybe you have a 'known good' laptop to test with? I'll bring one anyway. Sending PM a little later. Thanks very much.
I bought my "Enthusiast Version" about 2 years ago (to diagnose the airbag light on my Dad's 1999 Boxster), I have used it SO many times, especially in the last month or so (I bought a "fixer" C4S), I have had about 25 different CEL codes!
I think it is an awesome diagnostic tool.
OK, about yours.
I just saw your responses to JTT (I asked the same questions)
Have you watched the video about installing it?
You Tube
Aaron covers the details.
Paul
@Porschetech3
- thanks. Durametric arrived today (as did my Bentley book!). So my TRA (Range 1) numbers for both banks are hovering around -0.35 to -0.38. My FRA numbers are both hovering around 0.98. According to
@996love
, this means my 02 sensor are probably ok. And according to
Callas
, the TRA numbers mean the car is running rich at idle and it is taking away fuel in the Idle range. Callas goes on to say that if you have a faulty MAF sensor, "The TRA-RKAT numbers will be LOW or BELOW 0 and the FRA or FRAU numbers may be normal around 1" which seems like the condition I have. I also checked the air flow sensor values - they're 19-20 kg/h at idle, which seems a tad high? The MAF numbers on a 996 should be around 17 kg/h and are usually +/- 2 depending on the EVAP situation.
So based on this, my next step is to replace the MAF sensor (I have a new OEM one sitting at the ready) and see if these numbers change. Y'all let me know if you see flaws in this plan
Yes !, the -0.35 to -0.38 TRA/fuel trim verifies that your system is running rich and 99 times out of 100 the MAF Sensor is your Huckle-Berry..
The other 1% of the time can be split up between high-fuel pressure, sticking injectors, or temp sensor reading too cold., Temp Sensors rarely ever fail, injectors usually stop up or lean out, and fuel pressure normally fails LOW....
Using Durametric and the proper diagnostic procedure has "nailed it "
Done! Strangely, the TRA started at -0.38 and stayed there for a bit, and I assumed the plot was continuing to thicken. As I waited and thumbed through different values to monitor, the engine warmed up a bit, RPM's came down, and the TRA went to 0. Well, 0.05 but close enough. So - I guess I needed to get past that initial warm-up period? Anyway, things seem good. Headed to get my car inspected so I can get the registration renewed, which was the whole reason for the urgency. Thanks again, all
Yep, on Porsche "Oxygen Sensing" is the quick/ short term fuel trim and when it goes to the limit, it doesn't set the CEL, it starts to move the TRA ( long term fuel trim) until the Oxygen Sensing is happy or the TRA reaches a limit....if the TRA reaches a -0.36 or a +0.36 it sets a fault code and CEL...
This is a source reference. Confirm exact model applicability in the original material.
