xt2005bonbon Posted August 10, 2015 Share Posted August 10, 2015 Can you add on that plot the fuel learn value? Also, can you do the same plot but at idle? Like a 30 second idle? Link to comment Share on other sites More sharing options...
StkmltS Posted August 11, 2015 Author Share Posted August 11, 2015 (edited) 1. The chart I posted yesterday with fuel learn % added. 2. 50 seconds of idling I really appreciate your help! Edited August 11, 2015 by StkmltS My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted August 11, 2015 Author Share Posted August 11, 2015 log #1 doesn't look too bad really. A tuner can make some small tweaks to your tune to get the actual boost closer to your target boost. But you'd probably want to get the issue with that cylinder resolved before tuning. Log #2, i have no idea. Was it surging during that log? i couldn't feel any surging, and it definitely didn't feel like the log looks. I figured out why my plot showing boost vs boost target was so funky. It had two different pulls overlapped and it was connecting data points that weren't adjacent. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted August 11, 2015 Share Posted August 11, 2015 1. The chart I posted yesterday with fuel learn % added. 2. 50 seconds of idling I really appreciate your help! It looks like your learned values at idle are almost pegged to +15%, and yet the ecu is still trying to add more fuel. so there's definitely something going on here. This is with Covertrussian stage 0 tune as well right? Have you ever confirmed that your MAF sensor, and or o2 sensor are in good working order? Link to comment Share on other sites More sharing options...
StkmltS Posted August 11, 2015 Author Share Posted August 11, 2015 The 50 seconds of idle is on CR's stg0 tune but the pull is on the OEM tune. I'll do a pull tonight on my new tune. I haven't touched the O2 sensor, and I've only cleaned the connectors inside the MAF sensor harness. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted August 11, 2015 Share Posted August 11, 2015 fwiw, two months ago I was chasing a boost leak on my car. Turned out there was not boost leak but there were issues with the MAF sensor wiring harness . I found out by watching the fuel correct field while the car was idling; at the same time, I was fiddling with the MAF sensor wiring harness and stuff. And I could see instantly the fuel correct field reacting to my moves. I could not believe it... Anyways, point is you could always inspect and clean your sensor. Never hurts. And if you know someone who has a good working sensor, swap it out without resetting the ECU and watch the fuel correct/learn parameters. Also, just in case, lots of people confuse the IAT sensor with the MAF sensor. See below. Yup, green arrow points to IAT sensor, the red points to where the MAF wires are. Link to comment Share on other sites More sharing options...
Con.Harr91 Posted August 12, 2015 Share Posted August 12, 2015 I've been chasing misfire issues forever, really made me not enjoy driving the car. Finally took it to my mechanic with the assumption of it needing an engine rebuild (146k miles). After determining that it has 0% leakdown and 135psi cold compression across the board we started chasing other possible causes. It wasn't being caused by spark plugs, fuel injectors, coil packs, fuel pressure regulator, fuel pump, boost leaks, ecu, tune, engine harness grounds, or MAF sensor. We think it might be a combined issue of the headgasket on 2/4 and a valve issue. There was carbon buildup in the coolant overflow, so I definitely need to get the headgaskets done. Hopefully this finally solves my mystery misfire. '03 Forester X 5mt - Engine Seized at 262k miles. '05 LGT Wagon 6mt -MotoIQ.com Project Vehicle '13 VW Touareg TDI - Daily Torque Monster. Link to comment Share on other sites More sharing options...
StkmltS Posted August 12, 2015 Author Share Posted August 12, 2015 fwiw, two months ago I was chasing a boost leak on my car. Turned out there was not boost leak but there were issues with the MAF sensor wiring harness . I found out by watching the fuel correct field while the car was idling; at the same time, I was fiddling with the MAF sensor wiring harness and stuff. And I could see instantly the fuel correct field reacting to my moves. I could not believe it... Anyways, point is you could always inspect and clean your sensor. Never hurts. And if you know someone who has a good working sensor, swap it out without resetting the ECU and watch the fuel correct/learn parameters. Also, just in case, lots of people confuse the IAT sensor with the MAF sensor. See below. That's good info, I'll def look in to it. I've been chasing misfire issues forever, really made me not enjoy driving the car. Finally took it to my mechanic with the assumption of it needing an engine rebuild (146k miles). After determining that it has 0% leakdown and 135psi cold compression across the board we started chasing other possible causes. It wasn't being caused by spark plugs, fuel injectors, coil packs, fuel pressure regulator, fuel pump, boost leaks, ecu, tune, engine harness grounds, or MAF sensor. We think it might be a combined issue of the headgasket on 2/4 and a valve issue. There was carbon buildup in the coolant overflow, so I definitely need to get the headgaskets done. Hopefully this finally solves my mystery misfire. I fell like we could be good friends because we've gone through all of the same crap haha. It's a frustrating process isn't it. When is your new head gasket(s) happening? Are you going to get your valves cleaned up at while they're in there? My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
Con.Harr91 Posted August 12, 2015 Share Posted August 12, 2015 Yup, all the valves will be adjusted and cleaned up while its apart. He'll also be checking for cracked ringlands. While its apart its getting a new clutch/pressure plate/flywheel/blast plates too. '03 Forester X 5mt - Engine Seized at 262k miles. '05 LGT Wagon 6mt -MotoIQ.com Project Vehicle '13 VW Touareg TDI - Daily Torque Monster. Link to comment Share on other sites More sharing options...
StkmltS Posted August 12, 2015 Author Share Posted August 12, 2015 Yup, all the valves will be adjusted and cleaned up while its apart. He'll also be checking for cracked ringlands. While its apart its getting a new clutch/pressure plate/flywheel/blast plates too. Sounds like a ton of fun (AKA $$$$$). Why can't they make fun cars affordable and last forever? I cleaned my filthy MAF sensor on my lunch break and I'm holding my breath... My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted August 12, 2015 Share Posted August 12, 2015 I cleaned my filthy MAF sensor on my lunch break and I'm holding my breath... With MAF sensor cleaner right? Link to comment Share on other sites More sharing options...
StkmltS Posted August 12, 2015 Author Share Posted August 12, 2015 With MAF sensor cleaner right? Kroger brand hot sauce I don't like bragging, but I'm somewhat of a local legend for turning simple projects into DIY nightmares just to save a buck. But when it comes to messing with expensive-to-replace things (eg. MAF sensor), I'm a large financial supporter of the "right tool for the right job" club. So yes, I used CRC MAF sensor cleaner. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted August 12, 2015 Share Posted August 12, 2015 Kroger hot sauce . Do you know someone not far from you who has an LGT or OBXT, so you could borrow their working MAF sensor, just to rule that out? Link to comment Share on other sites More sharing options...
StkmltS Posted August 12, 2015 Author Share Posted August 12, 2015 (edited) My car doesn't know any other LGTs or OBXTs, but one of my neighbor's friends has a blobeye STI that may be willing to help out. Last night I went to a small Subaru gathering at a Sonic drive-in and there was an OBXT there. I guess I should have offered to buy them a milkshake as a trade for 5 minutes with their MAF sensor. But then again they ordered expensive shakes... My new vacuum hoses arrived and my wife+kids aren't going to be home until late tonight Edited August 12, 2015 by StkmltS My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted August 12, 2015 Author Share Posted August 12, 2015 No dice, my butt-o-meter detects no change in the idle. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted August 13, 2015 Share Posted August 13, 2015 So learned values are about the same then? Link to comment Share on other sites More sharing options...
StkmltS Posted August 13, 2015 Author Share Posted August 13, 2015 LV's haven't improved. Are there better parameters that I should be looking at? I'm really in the dark here and almost arbitrarily picking things to graph. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
Perscitus Posted August 14, 2015 Share Posted August 14, 2015 That Fuel Learn at idle seems high, its as-if the car has learned to add 15-20% fuel rather consistently to hit lambda targets... assuming 1 or close to 1 at warmed up idle. If so, it must be thinking its running lean and tries to add that much fuel to hit the CL fuel target. 150 seconds of Highway Fuel correct seems somewhat reasonable, withing +/-5% typically. Notice the see-saw fuel behavior toward the end? Your Fuel Learn tanked to 0% but the Fuel Correct picked right up to fill in the 'gap' and added 10-15% fuel on top of that 0%. But try not to vary the throttle that much, instead either keep it the same or increase/decrease gradually. Don't log any sudden throttle changes... tip-in and CL/OL, OL/CL transitions throw things off too much. What you should do to get a better picture of what's going on is add a third column where you add Fuel Lean #1 and Fuel Correct #1 and plot that instead (effectively same thing as LTFT + STFT). Can you also log and plot Fuel Learn #3 and Fuel Correct #3, Lambda #1, Closed Loop flag or CL/OL Fueling (so you can filter OUT all OL data points for now, easily) Other plots to consider....: Fuel Trims as a function of MAF g/sec Fuel Trims as a function of Load g/rev MAF v as a function of MAF g/sec Link to comment Share on other sites More sharing options...
StkmltS Posted August 14, 2015 Author Share Posted August 14, 2015 That Fuel Learn at idle seems high, its as-if the car has learned to add 15-20% fuel rather consistently to hit lambda targets... assuming 1 or close to 1 at warmed up idle. If so, it must be thinking its running lean and tries to add that much fuel to hit the CL fuel target. For that 90 seconds the average AFR (lambda) was 0.9715. After resetting the ECU it idles like crap until it learns it's way back up to 15%. At that point my rough idle becomes smooth, but the misfires still remain. 150 seconds of Highway Fuel correct seems somewhat reasonable, withing +/-5% typically. Notice the see-saw fuel behavior toward the end? Your Fuel Learn tanked to 0% but the Fuel Correct picked right up to fill in the 'gap' and added 10-15% fuel on top of that 0%. But try not to vary the throttle that much, instead either keep it the same or increase/decrease gradually. Don't log any sudden throttle changes... tip-in and CL/OL, OL/CL transitions throw things off too much. Aw, but where's the fun in that? I wasn't aware of how much it affects things so I'll work on being gentle with the throttle when logging. What you should do to get a better picture of what's going on is add a third column where you add Fuel Lean #1 and Fuel Correct #1 and plot that instead (effectively same thing as LTFT + STFT). Will do. Can you also log and plot Fuel Learn #3 and Fuel Correct #3, Lambda #1, Closed Loop flag or CL/OL Fueling (so you can filter OUT all OL data points for now, easily) Will do. Other plots to consider....: Fuel Trims as a function of MAF g/sec Fuel Trims as a function of Load g/rev MAF v as a function of MAF g/sec I logged my entire last couple of drives to/from work/home so I'll play around with the data during my down time. Thanks for the help! My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted August 18, 2015 Author Share Posted August 18, 2015 Where is this grounding strap supposed to connect to the engine? It's the one near the front driver side wheel. http://images.tapatalk-cdn.com/15/08/18/2b36c8cbd37e82d9a5a8073f29401d36.jpg Sent from inner space. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
rhino6303 Posted August 18, 2015 Share Posted August 18, 2015 Where is this grounding strap supposed to connect to the engine? It's the one near the front driver side wheel. http://images.tapatalk-cdn.com/15/08/18/2b36c8cbd37e82d9a5a8073f29401d36.jpg Sent from inner space. The threads next to the sheet metal piece on the head. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted August 19, 2015 Share Posted August 19, 2015 ^+1 Link to comment Share on other sites More sharing options...
StkmltS Posted August 19, 2015 Author Share Posted August 19, 2015 Thanks dudes. Looks like I need to dig through my bucket-o-bolts tonight. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted September 3, 2015 Author Share Posted September 3, 2015 (edited) Something strange is afoot... I haven't done anything to the motor since I last chimed in. *** See attached pic The car is idling rough like it usually does while re-learning the values. What's going on with my timing correction today? Is it possible that turning on my AC influenced this? I looked in my engine bay when I got home and everything seems to be as it should be. I had to get a new tire on 8/28. Obviously the tire shop reset my ECU, my guess is because they probably stalled it a time or two and the CEL turned on. I'm going to replace the broken grounding strap tonight and I'll drive it around for a while to see if I can get the timing to correct itself. Edited September 3, 2015 by StkmltS My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted September 3, 2015 Share Posted September 3, 2015 something happened on screenshot 4 because the IAM dropped. That causes the ECU try increasing timing (they are positive values) trying to instigate knock. If none is detected then it will eventually bump up IAM a little, reset the FLKC cells to zero, and this paragraph repeats until IAM is back to a full 1.000 There is a little more explanation in the "Timing Correction (degrees)" section in the BtSsm manual. BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now