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Title: M-Box Stage 2++ limp mode help request Post by: trichard3000 on August 22, 2012, 12:54:58 PM I've been running a tweaked version of the NOTORIOUS VR Stage 2++ tune and I keep getting kicked in and out of limp mode. Any advice on where to start ruling out hardware issues and where to modify the tune is greatly appreciated!
Current Tweaks: Bosch MAF, lowered LDRXN, Coded out rear O2's I'm obviously overboosting and I'm also getting a big knock spike when limp mode starts. During one pull of this test run I had a flashing CEL but it didn't stay on. I hadn't checked or cleared codes in a while so I can't say for sure that these happened at the same time, but my guess is that the misfires in Cyl's 4-6 happened on that pull. Here are all the codes (some don't matter): 18058 - Powertrain Data Bus: Missing Message from Instrument Cluster P1650 - 35-00 - - 17866 - Exhaust Gas Temp Sensor 2 (G236): Short to Ground P1458 - 35-00 - - 18014 - Rough Road/Engine Torque Signal from ABS: Electrical Malfunction P1606 - 35-10 - - - Intermittent 17869 - Exhaust Gas Temp Regulation for Bank 1: Implausible Signal P1461 - 35-10 - - - Intermittent 16684 - Random/Multiple Cylinder Misfire Detected P0300 - 35-00 - - 16688 - Cylinder 4: Misfire Detected P0304 - 35-00 - - 16690 - Cylinder 6: Misfire Detected P0306 - 35-00 - - 16689 - Cylinder 5: Misfire Detected P0305 - 35-00 - - These graphs are over time so you can see when the limp mode kicks in. I can't say that this log was for the same run that threw the misfires, but I could consistently get this to happen. Boost and throttle position: (https://lh5.googleusercontent.com/-o8xelo9RsIE/UDU3xtTFRLI/AAAAAAAAANo/nSW9kPpDw-8/s640/Ted_log_20120821_184827_boost.png) Knock - Note big knock spike at same time as overboost: (https://lh4.googleusercontent.com/-FDhgCi53ORU/UDU3xhC8V2I/AAAAAAAAANk/_dtoerpoh3Q/s640/Ted_log_20120821_184827_knock.png) Thanks again for any advice you can give! Title: Re: M-Box Stage 2++ limp mode help request Post by: nyet on August 22, 2012, 01:07:18 PM Probably torn wastegate lines or bad N75
Can clear codes and redo your log with WGDC as well? Also, run a separate log with N75 electrically disconnected. Title: Re: M-Box Stage 2++ limp mode help request Post by: trichard3000 on August 22, 2012, 01:22:02 PM WGDC is logged in the csv file. Here's WGDC on top of boost/time:
(https://lh6.googleusercontent.com/-4uA62RKtYTc/UDU-zCbQ7vI/AAAAAAAAAN8/VWP7mq9UnlU/s640/Ted_log_20120821_184827_wg.png) I'll try to get a log with the N75 unplugged in the next day or so. Thanks! Title: Re: M-Box Stage 2++ limp mode help request Post by: nyet on August 22, 2012, 01:26:19 PM N75 looks fine.
The PID needs to be redone for your hardware. Pull a bunch of I limit and maybe add some D perhaps even bring wg linearization down. Title: Re: M-Box Stage 2++ limp mode help request Post by: RS4boost on August 22, 2012, 01:27:21 PM I believe the both "Exhaust Gas Temp Sensor and regulation" DTC`s was the problem.
These sensors breaks often. In the last 3 years I have changed two sets (2x2) in my RS4. In all these cases my car runs into limp mode. 17866 - Exhaust Gas Temp Sensor 2 (G236): Short to Ground P1458 - 35-00 - - 17869 - Exhaust Gas Temp Regulation for Bank 1: Implausible Signal P1461 - 35-10 - - - Intermittent Title: Re: M-Box Stage 2++ limp mode help request Post by: phila_dot on August 22, 2012, 01:32:08 PM Do not tune an unhealthy car.
Get those codes fixed and then go from there. Title: Re: M-Box Stage 2++ limp mode help request Post by: nyet on August 22, 2012, 01:36:52 PM 2nd notion of fixing egts (or coding them out)
Sorry. I missed the fact that you didn't actually throw a deviation code. Misfires are probably from EGT enrich. Limp is from EGT failure. Title: Re: M-Box Stage 2++ limp mode help request Post by: trichard3000 on August 22, 2012, 02:35:06 PM Do not tune an unhealthy car. I couldn't agree more! I'm hoping that the logs point to an easily fixed HW issue so I can fix and get on with the SW goodness! :-) Would EGT failure have any impact on the overboost? Anyway, I'll code out EGT's and re-log. I have a spare set that are of unknown quality. If coding out works, I may try throwing these in and re-enabling EGT's. I'd rather have them as a a safety net. Prior to running this file, I was running an APR tune that never went into limp mode like this or overboosted (although I haven't logged with it lately). From time to time I would see EGT codes. Perhaps APR already ignores these? If limp then goes away and overboost remains, I'll go back to this: The PID needs to be redone for your hardware. Pull a bunch of I limit and maybe add some D perhaps even bring wg linearization down. Thanks for the advice. Title: Re: M-Box Stage 2++ limp mode help request Post by: nyet on August 22, 2012, 03:06:27 PM Overboost is (probably) unrelated to EGT - separate issue... like I said your PID needs some lovin.
That said, always fix the stuff you KNOW is broken first :) You never know what other problems will magically go away... Title: Re: M-Box Stage 2++ limp mode help request Post by: A6turbofrance on August 25, 2012, 08:40:02 AM CLACINS = 0 for p1650 error code
code out EGT or change it. any valve cover leak ? can cause the misfire error too if oil on spark plugs and boot Title: Re: M-Box Stage 2++ limp mode help request Post by: A6turbofrance on August 25, 2012, 08:40:56 AM 4-5-6 look a weak gasket on cover valve gasket , the rounds ones near spark plug
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