.Catalyst. Posted January 31, 2013 Author Share Posted January 31, 2013 I assume since they were Subaru specific NGKs that they didn't need gapping? My mechanic who installed them wrenches on Subarus daily and I can ask if he gapped them. I'm tempted to have him throw a new set in just to see. As someone who has been troubleshooting (IT) for close to 20 years, it's hard for me to rule out something that has recently changed that coincides with the beginning of the problem. My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
ehsnils Posted January 31, 2013 Share Posted January 31, 2013 Check battery voltage, alternator and ground. Also make sure that the battery connectors are in good shape - just to rule out that it's actually a voltage problem. What about fuel pressure? If the fuel pump is starting to give up it may end up causing trouble. And can you also log the exhaust temp and O2 sensors? Too high EGT may be triggering fail safe mode. Link to comment Share on other sites More sharing options...
.Catalyst. Posted January 31, 2013 Author Share Posted January 31, 2013 Already replaced the fuel pump with a DW65C without resolving the issue (This was my mechanics diagnosis). I logged battery voltage in those last logs and looks fine to me. I can definitely log additional parameters. EGT probe in the UP location has been removed and replaced with a resistor and CELs disabled in tune. My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
iNVAR Posted January 31, 2013 Share Posted January 31, 2013 fuel cut can occur regardless of how deep you have the accel pedal, it will always override your input to shut power down. whats bizzarre is you don't have a CEL, typically overboost/fc will throw a wastegate performance code. the mystery continues.... I could be mistaken, but if he hits FC and the throttle plate slams shut, it should show his "throttle opening angle" being reduced as well. Link to comment Share on other sites More sharing options...
1drwagon Posted January 31, 2013 Share Posted January 31, 2013 I've had the same problem with my 05 LGT. When I replaced the coils that seemed to fix it for a bit. The car has always seemed to idle rough though and not sure if those things are linked. But I also changed the plugs, and that didn't fix it. The engine just blew up on me - a couple days ago. And it looks like the compression in one cylinder was down to 40%. I would check the compression, and go from there. Check it quick , it could get very expensive if you don't get it fixed soon. Link to comment Share on other sites More sharing options...
.Catalyst. Posted January 31, 2013 Author Share Posted January 31, 2013 Mine idles quite smooth. I only changed plugs due to preventative maintenance, before that my car pulled strong at WOT to redline. If plugs seem suspect based on logs I can certainly do another compression check while they are out. You are saying you had a normal running car outside of a "Fuel Cut" at about 5K RPM under WOT only? My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
.Catalyst. Posted January 31, 2013 Author Share Posted January 31, 2013 Wow never really searched NASIOC for troubleshooting purposes. Every damn thread there gets plagued with useless trolling posts. Ugh. What I did see (both in descriptions and videos), is that there are other people that have experienced this same issue. Of course in 3 instances where symptoms were exactly the same, no one has posted an actual solution. Many posts related to plugs (gap), coil packs, and fuel pump wiring. Since I know my fuel pump is brand new and wiring is good (done after symptoms started), and this started right after having plugs installed, I'm going to pursue having another new set of plugs installed and have gap checked. If that isn't it then start trying coil packs. My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
Underdog Posted January 31, 2013 Share Posted January 31, 2013 Just out of curiosity, I'd be interested to see a log where you bring it up close to the "limit" and then actually let off the throttle completely. Interested to see if the car behaves the same way. I noticed in the first of the last three logs you posted that it occurred around 4700 RPM. Just an observation. The Crimson Dynamo Link to comment Share on other sites More sharing options...
.Catalyst. Posted January 31, 2013 Author Share Posted January 31, 2013 Would it be more useful to show like 75% throttle (which doesn't cut) to redline or WOT and lift completely before the event (depending on gear and load it seems to vary between 4700-5300RPM). My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
Underdog Posted January 31, 2013 Share Posted January 31, 2013 If I had to choose I would say WOT & lift. The Crimson Dynamo Link to comment Share on other sites More sharing options...
.Catalyst. Posted January 31, 2013 Author Share Posted January 31, 2013 That I can do. My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
Strizzy Posted January 31, 2013 Share Posted January 31, 2013 Also log crank position signal, if you can. My bad luck build Link to comment Share on other sites More sharing options...
.Catalyst. Posted February 1, 2013 Author Share Posted February 1, 2013 I'll have to add the crank position again and log. Here's a couple where I lift before the event occurs.romraiderlog_Troubleshooting_06LGT5MT_3rdwithLift_20130131_150828.csvromraiderlog_Troubleshooting_06LGT5MT_3rdwithLift_20130131_151417.csv My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
.Catalyst. Posted February 1, 2013 Author Share Posted February 1, 2013 Another update. Tried OEM BPV and no change. Quite a bit of oil blow by in the recirc line and the TMIC outlet where the BPV mounts. Oil level was a little high (Been 2 weeks since the 90K service and oil change and it was up to the twist after letting cool about 15 minutes after running). Other than that all other visual inspections looked good. I'm going to have the plugs exchanged for another new set. At this point I'll go insane if I don't rule that out. I will log CPS next time I log. Hoping I can get plugs done ASAP since this began when they were replaced. My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
ehsnils Posted February 1, 2013 Share Posted February 1, 2013 Good idea, and when you run next log please also log O2 sensors. Link to comment Share on other sites More sharing options...
.Catalyst. Posted February 1, 2013 Author Share Posted February 1, 2013 I believe I added the o2 sensors in the most recent logs, unless I missed a parameter in RR. My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
.Catalyst. Posted February 3, 2013 Author Share Posted February 3, 2013 Update: Plugs replaced and gap checked and verified. Issue is still present. Mechanic is at a loss. I'm definitely stumped as well. The saga continues... Also had him do a compression check while the plugs were being swapped and it looked good as well. At least I have that going for me! My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
ehsnils Posted February 3, 2013 Share Posted February 3, 2013 One idea is to do a valve clearance check, and also check that all valve springs are OK. Be aware that the valve clearance problem may not show up at a compression test since the temperature expansion of the valve stem changes that on a running engine. And a log containing bit 6 and 7 of SSM address 0x64 should give the Cam Position Sensor and Crank Position Sensor. If any of them are bad it should appear in the log by one of them "flickering". If you have a front O2 sensor you should log that too. Another thing to check is that all hoses are on right, and that you don't have a hose that's cracked and starts to leak during boost and then closes as soon as vacuum is restored. And you can skip logging some of the data that hasn't provided any clue earlier, like the following: Knock Sum* (count) Intake Air Temperature (F) IAM (1-byte)** (multiplier) A/F Sensor #1 (AFR) Battery Voltage (V) Exhaust Gas Temperature (F) And add the following: Tumble Valve Position Sensor Right Tumble Valve Position Sensor Left Intake VVT Advance Angle Right Intake VVT Advance Angle Left Link to comment Share on other sites More sharing options...
Underdog Posted February 3, 2013 Share Posted February 3, 2013 Nils, why do you suspect a valve clearance problem? This looks like a sudden event where, despite target & reported throttle positions being 100%, after the car has already reached full boost and with healthy timing and AFR readings, the MRP just drops off a cliff and in fact goes into full vacuum as if the throttle had slammed shut. All the other relevant parameters behave similarly, as if the throttle actually has closed (engine load, total timing, AFR, MAF voltage, IDC). The only thing that does act differently between logs with the event and logs where he lifts is the WGDC, which is expected given that when the boost drops off with 100% throttle, the WGDC will shoot up to try and recover. All roads lead back to a problem where there is, at a minimum, a physical restriction causing the engine to pull vacuum. A shut throttle plate or a hose getting sucked shut are the only things that make sense. The Crimson Dynamo Link to comment Share on other sites More sharing options...
Underdog Posted February 3, 2013 Share Posted February 3, 2013 Here are plots of a run with the event (1st) and when he lifts off prior to it (2nd). Both are in 3rd gear. Notice how the MAF voltage starts to drop off in the log with the event, and it starts to drop just before the precipitous decline in MRP. The WGDC is also climbing slowly before pegging at the ~67% mark. It makes sense (to me) that the WGDC needs to climb to maintain boost pressure as RPMs rise, but whether this profile looks normal or not, I can't say. With event http://imageshack.us/a/img443/2103/3rdwevent.jpg Lift prior to event http://imageshack.us/a/img844/8179/3rdwlift.jpg The Crimson Dynamo Link to comment Share on other sites More sharing options...
iNVAR Posted February 3, 2013 Share Posted February 3, 2013 would the tgv choke the intake enough to shoot into vacuum like that? Link to comment Share on other sites More sharing options...
Underdog Posted February 3, 2013 Share Posted February 3, 2013 I would be surprised. Hard to imagine a shut TGV chokes it enough to go full vac, but it is worth considering. You can log the tumble valve position left & right if you want. *Edit: NOPE. See posts #87 and 88 below.* Also meant to mention that I think it is unlikely that it is an AVCS problem. Add the parameters to your log if you want, but you are just decreasing sample time and making more clutter to wade through, IMO. The Crimson Dynamo Link to comment Share on other sites More sharing options...
iNVAR Posted February 3, 2013 Share Posted February 3, 2013 hmm, no... disregard... now that I think about it, tgv wouldn't cause this. I don't think the map sensor is located post tgv so if they slammed shut, it still wouldn't read vacuum like that. I think... Link to comment Share on other sites More sharing options...
Underdog Posted February 3, 2013 Share Posted February 3, 2013 hmm, no... disregard... now that I think about it, tgv wouldn't cause this. I don't think the map sensor is located post tgv so if they slammed shut, it still wouldn't read vacuum like that. I think... Correct. MAP sensor is plumbed off the center plenum of the intake manifold, upstream from TGV. The Crimson Dynamo Link to comment Share on other sites More sharing options...
iNVAR Posted February 3, 2013 Share Posted February 3, 2013 I'm on mobile so it's hard for me to check the whole thread again.Is the bov venting when the event occurs? Link to comment Share on other sites More sharing options...
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