Ryanman Posted February 3, 2015 Share Posted February 3, 2015 Let me preface by saying that I have been searching the forums for months on this issue, with many similar issues that appear to have solved others issues. STOCK Car 150k miles Issue; Between ~2k Rpm to ~3k Rpm, the 05 Subaru Legacy GT 5speed MT, will randomly act however it wants, with symptoms mostly consisting of, 1.Wild bucking up and down in rpm range. 2.Hesitation when trying to accelerate, when it feels as if the car is slowing down, and you go to apply gas, it slows down even more, so you either, give it more gas, or downshift. If you give it more gas is goes even slower, then you get mad at it and floor it and it goes even slower... Sometimes when you downshift, it continues to go slow if the rpm is below 3k, if it's above 3k, it takes of like a bat out of hell rocketing up in acceleration and throwing you back in the seat. This mostly occurs more frequently when it's colt started, but still occurs at the worst time when you are driving slow in a high gear. I have performed all of the following: 1.Battery Terminal Cleaning. 2.Battery Replacement. 3.Accelerator pedal connector cleaning 4.Throttle body Cleaning. 5. Fuel injector cleaner. 6. Multiple multiple new tanks of gas 7. Oxygen Sensor Replacement with OE 8. Both OCV replacements 9. Ran direct wastegate pressure, bypassing the BCS 10. Re-flashed the ECU with linear throttle maps, 11. Re-flashed the ecu with stage 1 maps 12. Reflashed the ecu to stock maps. 13. MAF cleaning with MAF cleaner 14. Knock Sensor Replacement 15. Knock Sensor relocation, just to test, its back to stock now 16. Tested for a blown head gasket (combustion gases were not present in the Coolant) 17. Changed the oil... 2 times since event with Castrol Synthetic, european blend. The issue always "appears to go away" anytime I reset the ECU, and it does for a while, then comes back within a few miles of driving. I have data logged the car, however I have never gotten a good datalog of the event, and it is so spontaneous when it happens, but I swear it happens everytime I drive it. But when I have I have never logged any misfirecounts, which is why I have not messed around with my spark plugs or coils yet I feel that there is no need since there is a very stable Idle, it does not surge under idle, or act funny when in neutral. *Other issues is that I can't consistently get my VAG-COM cable, or Tactrix cable to consistently connect with my ECU for logging* I am out of Ideas, and almost out of money, if you guys have any real ideas for things that might stand out please let me know. This is my daily driver, and isn't being a very good commuter car if it keeps acting like this, I'm always doing 20mph in 35 zones because the car will not go! =( Link to comment Share on other sites More sharing options...
MrTris Posted February 4, 2015 Share Posted February 4, 2015 Vehicle Speed Sensor? Link to comment Share on other sites More sharing options...
gimpydingo Posted February 4, 2015 Share Posted February 4, 2015 Bad cat? That can cause the bucking issue and lack of power. Others will chime in, but you should do some searching on here and may find your answer. Link to comment Share on other sites More sharing options...
MrTris Posted February 4, 2015 Share Posted February 4, 2015 Have you pulled the turbo and checked to see that it's in fact boosting? How about the turbo to TMIC and TMIC to TB connections? Hoses all tight? Link to comment Share on other sites More sharing options...
Ryanman Posted February 4, 2015 Author Share Posted February 4, 2015 If I reset the Ecu, then it runs fine and boost great. But I think its only while in learning mode. And it doesnt happen all the time. Link to comment Share on other sites More sharing options...
boxkita Posted February 4, 2015 Share Posted February 4, 2015 still occurs at the worst time when you are driving slow in a high gear. Have you had any tuning done it? There is a known stumble in that range that can be somewhat fixed by tuning. I always used a lower gear to keep the revs up, however, bad for mpg Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
Ryanman Posted February 4, 2015 Author Share Posted February 4, 2015 Ive put about 20k miles on this car before the issue, there really shouldnt be anything that needs tuning. And no the car is stock. Link to comment Share on other sites More sharing options...
gimpydingo Posted February 4, 2015 Share Posted February 4, 2015 Ive put about 20k miles on this car before the issue, there really shouldnt be anything that needs tuning. And no the car is stock. The car is stock, that IS the reason to get it tuned. The OEM map sucks. Knock, Knock. Who's there? Shitty Map. Shitty Map Who? Shitty OEM Subaru map knocking my poor engine to death. Link to comment Share on other sites More sharing options...
Ryanman Posted February 4, 2015 Author Share Posted February 4, 2015 The car is stock, that IS the reason to get it tuned. The OEM map sucks. Knock, Knock. Who's there? Shitty Map. Shitty Map Who? Shitty OEM Subaru map knocking my poor engine to death. Ok Mr closed loop tuning expert, what specific part of modifying my ecu's pareters is going to directly affect this? And how is that type of tuning accoplished? Obviously taking it to extreme turbo tuner joe shmo for an open loop tune will not fix my part throttle closed loop disfunction. There must be some legitimacy as to some root cause to this, and having the exact same tune for 140k miles, then suddenly blaming the tune, 1. Doesn't solve anything, and doesn't really even pin-point any specific flaw in the tuning. Does anyone know of which parameters to datalog for this which could be of great help? Or what a fixed map looks like? Link to comment Share on other sites More sharing options...
iNVAR Posted February 4, 2015 Share Posted February 4, 2015 Your first step honestly should be to post learningviews and datalogs. If you can't get a datalog of the event because you never seem to be catching it, then you're not trying hard enough. You should be datalogging EVERY DRIVE until you catch it. And you should catch it several times. Link to comment Share on other sites More sharing options...
Ryanman Posted February 4, 2015 Author Share Posted February 4, 2015 My cables don't seem to ever want to connect, and it sucks because I bought both the cheap vag-com, and the expensive tactrix cable. Does anyone have a specific cable that they reccoment for logging that is reasonable? Link to comment Share on other sites More sharing options...
Ryanman Posted February 4, 2015 Author Share Posted February 4, 2015 Attached is a video of the problem to emphasize what it is doing. cold start Warm start Link to comment Share on other sites More sharing options...
boxkita Posted February 4, 2015 Share Posted February 4, 2015 My cables don't seem to ever want to connect, and it sucks because I bought both the cheap vag-com, and the expensive tactrix cable. Does anyone have a specific cable that they reccoment for logging that is reasonable? did you buy the tactrix cable only or get the whole kit (has the peice to plug into the obd connector) ? Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
boxkita Posted February 4, 2015 Share Posted February 4, 2015 Ok Mr closed loop tuning expert, what specific part of modifying my ecu's pareters is going to directly affect this? And how is that type of tuning accoplished? Obviously taking it to extreme turbo tuner joe shmo for an open loop tune will not fix my part throttle closed loop disfunction. So...this is the part where you need to be nice. There must be some legitimacy as to some root cause to this, and having the exact same tune for 140k miles, then suddenly blaming the tune, 1. Doesn't solve anything, and doesn't really even pin-point any specific flaw in the tuning. There is a known flaw in the stock tune. That you didn't notice until now? Or maybe you did given the long list of replacement parts. Does anyone know of which parameters to datalog for this which could be of great help? Or what a fixed map looks like? Moving you to the Tuning section where you will can find more specific help. And also where you can read for the answers to your questions Build my car Boxkita Track days Link to comment Share on other sites More sharing options...
MikeyPSF Posted February 4, 2015 Share Posted February 4, 2015 My cables don't seem to ever want to connect, and it sucks because I bought both the cheap vag-com, and the expensive tactrix cable. Does anyone have a specific cable that they reccoment for logging that is reasonable? Hey there, I'm Mike from Tactrix. If you're having trouble connecting with your OpenPort, send us an email directly to support at tactrix dot com and we'll help you get the issue sorted. -Mike Link to comment Share on other sites More sharing options...
iNVAR Posted February 4, 2015 Share Posted February 4, 2015 Flashing when you have connection problems is unwise. Link to comment Share on other sites More sharing options...
5thElement Posted February 12, 2015 Share Posted February 12, 2015 I am also new to my LGT so knowledge is limited, I have seen articles on NASIOC about this issue and sometimes the issue was the crankshaft position sensor. Some had metal shavings attached and some were damaged, or faulty. Ffter cleaning or replacing there was improvement. Not sure if this is the case here but thought it was worth mentioning. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted February 12, 2015 Share Posted February 12, 2015 I would think there's something vibrating somewhere around that rpm range which would trigger the knock sensor and would pull excessive timing. It may not necessarily learn it though. I am experiencing a somewhat similar behavior: around 2700 ish rpm, not necessarily under load, I get stupid FKC of around -6 deg max, and as I leave that rpm range, it slowly decreases. And of course, power is down while this occurs so it feels like bucking a bit. It's now been a week and it still has not registered it as FLKC (i.e. LV is clean and A/F trims are within reasonable ranges +/-5%) Been monitoring this issue with this tool (http://legacygt.com/forums/showthread.php/btssm-bluetooth-adapter-app-229709.html). Loving it as I can clearly see when it is happening as I drive. Link to comment Share on other sites More sharing options...
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