LPStandard Posted March 22, 2017 Share Posted March 22, 2017 Ok. :spin: My fiancee's 05 LGT has excessive A/F Learning at idle, along with continually worsening knock issues. I've been all over this car, covered all of the common problems and some off the wall stuff too. I'm seeing 14-15% fuel trim at idle. Some negative fuel trim at higher loads, which led me to believe there was a boost/vac leak somewhere. Did a smoke test and a boost leak test, couldn't find anything readily apparent. Visual inspection showed some oil film at the TB gasket and coupler. Replaced the TB gasket, corrected the clamps on the coupler, replaced the TGV and lower IM gaskets, clamped, replaced, fixed any loose vacuum lines, even went as far as to test a replacement intercooler. Tested the BPV. Injectors have been serviced, A/F sensor is recent. I have replaced the fuel filter (PITA that was). I have several logs if anyone would like to take a look. I'm starting to wonder if the injectors aren't done, regardless of the cleaning. They were professionally serviced and the printout shows improved flow back to rated flow rate. (2 were about 15% lean) Yet, no change in my idle trim. The car doesn't quite make it to the boost targets, but from what I've been reading its pretty normal. No abnormal noises or logged misfires. Ideas? Before I shotgun a set of injectors? EDIT: I apologize for the length of the log, its a decent drive cycle with several driving styles, including WOT. The car is a 5AT.romraiderlog_20170321_19 3707after filter.csv Link to comment Share on other sites More sharing options...
LPStandard Posted March 22, 2017 Author Share Posted March 22, 2017 I should also add that the car is near stock. Previous owner deleted the airbox silencer, and my only modification is a Grimmspeed catless up pipe to prevent ugly catalyst turbo failure. Link to comment Share on other sites More sharing options...
Max Capacity Posted March 22, 2017 Share Posted March 22, 2017 You might want to ask one of the Tuners for help, but remember they may help out for free, but you should remember that when it comes time to buy things for your car. covertrussian is pretty good with these type questions too. Check out his threads. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
LPStandard Posted March 22, 2017 Author Share Posted March 22, 2017 Thing is, I have the tools and ability to tune around what I'm seeing here. I just don't want to bandaid an issue like this. There has to be something I'm missing. I'm fairly certain that fixing the CL/OL delay would alleviate the FLKC I'm getting after freeway driving. The catless up pipe is spooling the turbo faster on the freeway. 30% throttle or so in 5th puts me right across the RPM/load range where the correction is happening, and logs show the car overshooting the boost target while still CL and about .98-1.0 lambda. My main concern is the insane fuel trim at idle. Tells me there is definitely something out of whack. Maybe there is a boost/vac leak I missed... The positive idle correction, negative at high load, knock... Everything seems to point to that from what I can tell, I just dont see where it could be.romraiderLTV_20170319-170227 before filter.csv Link to comment Share on other sites More sharing options...
Max Capacity Posted March 22, 2017 Share Posted March 22, 2017 Here's the easy why to get him, send him a PM. http://legacygt.com/forums/showthread.php/tuning-fuel-economy-230552.html 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
covertrussian Posted March 23, 2017 Share Posted March 23, 2017 How does your inlet look? A lot of times they are falling apart and sucking in unmetered air. The silencer removal will mess with fuel trims a bit. I would try to get another one, or use a gatorade cap to seal it up. I don't think it's your injectors since you've had them cleaned and all I would also clean the MAF with some proper MAF cleaner. Finally O2 sensor could be acting up too. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 23, 2017 Author Share Posted March 23, 2017 How does your inlet look? A lot of times they are falling apart and sucking in unmetered air. The silencer removal will mess with fuel trims a bit. I would try to get another one, or use a gatorade cap to seal it up. I don't think it's your injectors since you've had them cleaned and all I would also clean the MAF with some proper MAF cleaner. Finally O2 sensor could be acting up too. The inlet looked OK. Some oil saturation, but no cracks or damage that I could see when I had the intake off. That said, I might need to take a closer look I guess. I'll put smoke to it again this weekend. I'll seal the hole in the airbox and see what happens. Might be able to find another silencer also. The MAF is recent (6mo) and OE. Forgot to mention that. We've got a 3500mi road trip coming up in two months. I have to sort this out before then haha. Link to comment Share on other sites More sharing options...
Max Capacity Posted March 23, 2017 Share Posted March 23, 2017 If the intake is off the car, I'd replace the inlet tube. Piece of mind of priceless. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
LPStandard Posted March 23, 2017 Author Share Posted March 23, 2017 If the intake is off the car, I'd replace the inlet tube. Piece of mind of priceless. Actually its about $100 hahaha Link to comment Share on other sites More sharing options...
covertrussian Posted March 24, 2017 Share Posted March 24, 2017 The inlet looked OK. Some oil saturation, but no cracks or damage that I could see when I had the intake off. That said, I might need to take a closer look I guess. I'll put smoke to it again this weekend. Does the smoke test pressurize the tubing? Some leaks wont show up until there is boost or vacuum to open the holes up. But, you wouldn't have that high of correction from a hole like that. Are you sure it's a fairly stock tune? Actually its about $100 hahaha You can get them a good bit cheaper used here on the forums. I picked one up as a spare myself (even though I have a silicon one currently). 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 24, 2017 Author Share Posted March 24, 2017 The smoke test does pressurize the system, but only about 1/2psi. Most smoke testers are designed for EVAP systems. That said, I have always been able to find a vac leak with the smoke test. I'll recheck and confirm. Pressurize a bit higher if needed. Tune is stock. I've compared it to a known original ROM, as well as the "stage 0" from COBB. Link to comment Share on other sites More sharing options...
covertrussian Posted March 24, 2017 Share Posted March 24, 2017 Be careful with too much pressure, you can actually pop the cam and crank seals out (remove the oil fill cap to reduce pressure). How are all of your vacuum hoses looking? Maybe one of the popped off (can happen since most connections are not barbed). There is the infamous blue tee under the intercooler that could be causing this. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 25, 2017 Author Share Posted March 25, 2017 Be careful with too much pressure, you can actually pop the cam and crank seals out (remove the oil fill cap to reduce pressure). How are all of your vacuum hoses looking? Maybe one of the popped off (can happen since most connections are not barbed). There is the infamous blue tee under the intercooler that could be causing this. Pressure tested and re-smoke tested. No visible/audible leaks. Blue tee has been inspected and clamped when I had the manifold off, same with every other line/hose that sees boost or vac. Thing is, the system doesn't hold pressure (when pressurized at the turbo inlet). I know its safe to smoke test with the oil cap on (PCV system closed loop then. No outlet for pressure), because it only hits 1/2 psi or so. There's definitely a slow leak, but no visible smoke ANYWHERE... So frustrating. I'm considering just altering the maf scaling at idle and forgetting about it haha but I know that isn't the right way to do things. Anyway, here's the latest LTVs after about 100mi of driving. Mostly cruising, but some high load etc. EDIT: Go ahead and ignore the IAT in this LTV. The MAF was unplugged for the smoke test when I pulled it. Link to comment Share on other sites More sharing options...
covertrussian Posted March 27, 2017 Share Posted March 27, 2017 You know, 11% is not too bad. I get that high of adjustment in the summer, but in the winter I'm getting 1%. But I do have the idle portion of closed loop map a little leaner, which could be why mine gets high. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 27, 2017 Author Share Posted March 27, 2017 I know, and the car really does run well. I zeroed out the cl/ol delay for safety and I think I'm just going to leave it. Link to comment Share on other sites More sharing options...
covertrussian Posted March 27, 2017 Share Posted March 27, 2017 It's actually a different table, it's this one: http://legacygt.com/forums/attachment.php?attachmentid=246801&stc=1&d=1490590135 See how the idle cell's are calling for more fuel then the rest, I set mine to pull more fuel like the neighboring cells. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 27, 2017 Author Share Posted March 27, 2017 Adjusting the CL target compensation shouldn't move the fuel trims though, should it? Unless I'm mistaken, the fuel trims are adjusting IPW to reach that final AFR target based on input from the A/F sensor. Adjusting the AFR target compensation (in this case by about -.03 lambda), shouldn't effect the trims right? Just modify the base IPW that the trims are adjusting? Also, I cant seem to find a table for the actual CL fuel targets... Is the ecu just targeting stoich full time and adding these compensation tables (ECT and load)? Seems a little off to me, as my car is running a .99-1.0 lambda target at idle. If the CL target was 1.0 (stoich), with an additive adjustment of -.441 AFR (-.03 lambda w/ gasoline), wouldn't the final target be around .97 lambda? Link to comment Share on other sites More sharing options...
covertrussian Posted March 27, 2017 Share Posted March 27, 2017 It shouldn't, but there might be other areas of the tune that are not too happy about it. CL targets are actually done through the open loop fuel map, if it's 14.7 it's in CL. One thing to check is the FPR, I want to say that going away from the stock horrendous mess to simple STI FPR has helped me since my LV right now is 1%, but won't know for sure until warmer months are here. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 27, 2017 Author Share Posted March 27, 2017 I forgot to mention that I did actually verify fuel pressure with a mechanical gauge on Saturday. Right at spec idling both with and without vacuum applied to the regulator. Link to comment Share on other sites More sharing options...
LPStandard Posted March 27, 2017 Author Share Posted March 27, 2017 After looking at this, I'm not sure if its worth worrying about... Subaru doesn't warrant even setting a DTC until the total fuel trim is over 40%! They judge "normal" as under 19%... I'm blown away that the "normal" fuel trims are this wide. Just seems... lazy... on Fuji's end.05 LGT P0171.pdf Link to comment Share on other sites More sharing options...
covertrussian Posted March 27, 2017 Share Posted March 27, 2017 Well they say that when max ECU allowed learning is 15%. I wonder if the two values are not on same scales? 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
LPStandard Posted March 27, 2017 Author Share Posted March 27, 2017 Well they say that when max ECU allowed learning is 15%. I wonder if the two values are not on same scales? The max learning value is 15/-15, correct. The formula for pass/fail judgement is (actual lambda - target lambda) + correction + learning. If that total value exceeds the threshold value then a fault is set. At the airflow range near idle for the threshold table (0.0 g/s - 2.4 g/s) the threshold value is 40%! That means you would have to peg both trims full positive and still not have the desired lambda value to set a fault. Link to comment Share on other sites More sharing options...
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