xt2005bonbon Posted November 18, 2015 Share Posted November 18, 2015 do you run btssm at all times? How does roughness behave at idle? Does it go crazy between 0-99? Link to comment Share on other sites More sharing options...
StkmltS Posted November 18, 2015 Author Share Posted November 18, 2015 My OTG cable broke a couple weeks ago so I haven't logging in a while. I wish I had data from yesterday. My new cable will be here this weekend with my gaskets. Attached is a scatter plot from my last relevant log with significant time at idle. Typically the roughness count doesn't go above 25, I can't remember the last time that it went above 50. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted November 18, 2015 Share Posted November 18, 2015 Fascinating graph! Forgive me if you already stated this, but cyl #2 roughness counts climb quickly at idle, but as soon as rpm increases (like driving) roughness completely ceases? 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...
xt2005bonbon Posted November 18, 2015 Share Posted November 18, 2015 It looks like it. Did you ever check your valve clearance with the timing belt on? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 18, 2015 Share Posted November 18, 2015 btw, that's what happens to me on my 06 but only when the engine is getting to (but not quite) operating temperature. Although when you just start her up, it does not do it right away (probably due to higher idle rpm). But once @ operating temp, roughness is completely gone. So my vote (for my case) is ringland , even though it's been a year like this and has not gotten worse in 15k of driving. Particularly shows up if it is getting colder outside too. Link to comment Share on other sites More sharing options...
StkmltS Posted November 18, 2015 Author Share Posted November 18, 2015 Fascinating graph! Forgive me if you already stated this, but cyl #2 roughness counts climb quickly at idle, but as soon as rpm increases (like driving) roughness completely ceases? Sometimes it looks like that, but when the car isn't moving increasing the RPM doesn't help. It makes no sense, but it seems like an odd combination of RPM, speed, and manifold pressure. It looks like it. Did you ever check your valve clearance with the timing belt on? I did (from post 246): Measured valve clearances post-VJ: Cyl#2 intake: .007" (unchanged) Cyl#4 intake: .007" (unchanged) Cyl#2 exhaust: .014" (was .008") Cyl#4 exhaust: .013" (was .012") btw, that's what happens to me on my 06 but only when the engine is getting to (but not quite) operating temperature. Although when you just start her up, it does not do it right away (probably due to higher idle rpm). But once @ operating temp, roughness is completely gone. So my vote (for my case) is ringland , even though it's been a year like this and has not gotten worse in 15k of driving. Particularly shows up if it is getting colder outside too. Don't say the R-word! Neither engine temp nor air temp increases or decreases the severity of my misfire. It happens, always. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 18, 2015 Share Posted November 18, 2015 Oh well you know, I don't really mind having to rebuild it. It will be a nice learning experience. But I would not mind avoiding it at the same time, cause wife's due in ~June 2016... Did you ever see the condition of the valves? Burnt valve? Link to comment Share on other sites More sharing options...
heiche Posted November 18, 2015 Share Posted November 18, 2015 Sometimes it looks like that, but when the car isn't moving increasing the RPM doesn't help. It makes no sense, but it seems like an odd combination of RPM, speed, and manifold pressure. So when it's idling and misfiring, does it stop if... -the 5MT is in gear? (with clutch depressed) -if you slightly drag the clutch? (with parking brake on) -the A/C is on or off? 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...
StkmltS Posted November 18, 2015 Author Share Posted November 18, 2015 What do you mean by 'drag the clutch'? Sent from inner space. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted November 18, 2015 Share Posted November 18, 2015 When in first gear, start letting out the clutch like you'd do to drive forward, but just to the point that the rpm drops a little, and hold it there for a few seconds to see if the misfire goes away. Obviously you don't want to do that for very long as it's not good for the clutch Just wondering if you can influence the misfires by doing different things. I don't know what that would mean, just wondering 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...
heiche Posted November 18, 2015 Share Posted November 18, 2015 Oh well you know, I don't really mind having to rebuild it. It will be a nice learning experience. But I would not mind avoiding it at the same time, cause wife's due in ~June 2016... Congrats! 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...
RayC Posted November 19, 2015 Share Posted November 19, 2015 Been having a random misfire cyl 1 for a few months- and have been following this thread. Started with the easiest things first - replaced plugs, then swapped coils, then bought a spare set of injectors and tried those out. Still was random misfire cyl 1. Car ran perfectly under cruise and load, hot idle would stumble / misfire. Turns out burned exhaust valve cyl 1, which reading more is fairly common with the stock OEM tuning. I should have my heads back from the machine shop in a day or two. Full valve job, new exhaust valve guides, valve lash set, resurface the heads, and new seals. Also doing the timing belt, tensioner, idler, and obviously any gasket I touched upon disassembly. I'm also taking advantage of having my car apart and I'm replacing my turbo inlet with the perrin unit - the oem one was looking a bit ragged and I'd rather not risk tearing it at the 11th hour when this car is my daily. Figured I'd share. Can't wait to get my car back together. Been driving a sonata. Needless to say it's less than exhilarating, but the 30mpg is nice. Link to comment Share on other sites More sharing options...
StkmltS Posted November 19, 2015 Author Share Posted November 19, 2015 Oh well you know, I don't really mind having to rebuild it. It will be a nice learning experience. But I would not mind avoiding it at the same time, cause wife's due in ~June 2016... Did you ever see the condition of the valves? Burnt valve? In Steve Urkel's voice "Did I say that?" The dichotomous emotions of one who's owned by a Subaru... I haven't seen the valves yet. When I had the IM off my OTG adapter was lost deep behind the steering column so I couldn't use my boroscope. At the time I didn't think to use the scope with my laptop. When I get around to deleting the TGV's I'll scope 'em out. Even then I'll only be able to see the valve stems, right? So when it's idling and misfiring, does it stop if... -the 5MT is in gear? (with clutch depressed) -if you slightly drag the clutch? (with parking brake on) -the A/C is on or off? 1. Still misfires 2. Hard to tell, but it still sounds like it's there (FWIW the misfire was present before I replaced my clutch/FW goodies last winter) 3. The A/C doesn't affect the misfire either way How does the ECU determine the roughness count? It's probably worth mentioning that much of the time that I can hear and feel it misfiring, logging with BtSsm/RomRaider shows zero roughness. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 19, 2015 Share Posted November 19, 2015 Somehow, I am really starting to think you have a burnt valve. You did check the cylinder wall with your borescope and did not see any marks right? Link to comment Share on other sites More sharing options...
heiche Posted November 19, 2015 Share Posted November 19, 2015 Yeah that makes sense. Let's say a valve has a small crack or is slightly warped - basically it doesn't seal fully. At idle when compression of the mixture is very slow, the leak is just big enough to let by enough compression to induce a misfire. Now rev it up and compression is occurring much quicker, it's simply not enough time to bleed off the compression to cause a misfire. So basically a bad valve could explain why it only misfires at idle. 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...
StkmltS Posted November 19, 2015 Author Share Posted November 19, 2015 (edited) Somehow, I am really starting to think you have a burnt valve. You did check the cylinder wall with your borescope and did not see any marks right? I boro'd the cylinder but I couldn't see the walls because the mirror attachment is too crappy. All I could see was a normal looking piston. Yeah that makes sense. Let's say a valve has a small crack or is slightly warped - basically it doesn't seal fully. At idle when compression of the mixture is very slow, the leak is just big enough to let by enough compression to induce a misfire. Now rev it up and compression is occurring much quicker, it's simply not enough time to bleed off the compression to cause a misfire. So basically a bad valve could explain why it only misfires at idle. To be more precise, it only misfires under vacuum. It still occurs at high RPM when MPH=0, and I have a few logs where it sporadically showed up when MPH>0 (not a continuously rising count though). Maybe I can find a way to shove the borescope in the spark plug hole backwards > looking up at the valves. Attached image is just for amusement. Edited November 19, 2015 by StkmltS My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted November 19, 2015 Author Share Posted November 19, 2015 Been having a random misfire cyl 1 for a few months- and have been following this thread. Started with the easiest things first - replaced plugs, then swapped coils, then bought a spare set of injectors and tried those out. Still was random misfire cyl 1. Car ran perfectly under cruise and load, hot idle would stumble / misfire. Turns out burned exhaust valve cyl 1, which reading more is fairly common with the stock OEM tuning. I should have my heads back from the machine shop in a day or two. Full valve job, new exhaust valve guides, valve lash set, resurface the heads, and new seals. Also doing the timing belt, tensioner, idler, and obviously any gasket I touched upon disassembly. I'm also taking advantage of having my car apart and I'm replacing my turbo inlet with the perrin unit - the oem one was looking a bit ragged and I'd rather not risk tearing it at the 11th hour when this car is my daily. Figured I'd share. Can't wait to get my car back together. Been driving a sonata. Needless to say it's less than exhilarating, but the 30mpg is nice. Sounds like you're on the road to recovery. How did they/you diagnose the burnt valve? Keep me posted on how it runs after you get it all back together again. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
RayC Posted November 20, 2015 Share Posted November 20, 2015 diagnosis was pretty straight forward: Repetitive P0301's after fixing the usual symptoms I read on here (plugs, coil packs, injectors) Read this thread. Compression check showed Cyl 1 @ 60psi where the others were consistent at 135-140 - at that point I knew I had to pull the engine, so we did, pulled the heads and Exhaust valve on cyl 1 was shot. Taking advantage of the whole situation - while I'm out of my car for a few weeks I'm cleaning up the intake manifold, replaced the inlet with a perrin unit, and am going to freshen up all gaskets / timing assy, etc. Total bill thus far is just a touch under 2k - head work was $1190, gaskets from Subaru (any we touched) was just under $340 with a 25% discount (friend has an account there and my car is at his place), timing assy was $195 from amazon (go gates!). My car's been paid off since 2008, has 182k miles, so I figure she doesn't owe me a dime. I've been a ford guy for all my projects, but honestly my Subaru has been the most pleasurable car to drive. Just - does - it - all - right. I haven't checked this thread recently to see if you've done a compression or leakdown, but if you haven't, I'd do that next. Researching here and other places, these cars are prone to burn exh. valves in cyl 1 and 4. Once I recover financially I'm going to do a bit of a custom tune to help make the system safer than stock, while probably adding a little bit of power. Good to have friends in the right places, I guess. All that being said I should probably sell the set of injectors I bought for diagnosis. Link to comment Share on other sites More sharing options...
StkmltS Posted November 20, 2015 Author Share Posted November 20, 2015 (edited) Checking the compression was one of the first things I did. The numbers were consistent across all four cylinders, but they were extremely low; I'm saying because I tested the motor when it was cold. Who knows, maybe all of my valves are jacked and cyl#2 is the only one mad at me enough to misfire. Now that I'm [very] familiar with my engine bay it would probably be wise to do another compression test with the motor hot. When I tested it last January I was concerned that I wouldn't be able to pull the plugs very quickly and I didn't want to test each cylinder at a different temp. Everyone would probably agree that I should have pulled my motor a long time ago to see exactly what's going on in there. I haven't done that yet because I right now I don't have the cash to fix whatever big problem I may discover (cracked piston, head job, etc), and I'm not about to pull the motor apart and put it back in without 100% fixing the problem. Hoping the motor doesn't go chug-a-chug-a-ka-boom before I'm ready, I decided to take the cheap (& frustrating) route and work my way through all of the $0-$200 potential fixes that I can imagine. I've only been spending money on things that would eventually get replaced anyways (except an injector), so the only thing I'm out is time and frustration. After my wife and I are out of debt (our goal is Christmas) I'll be able to save for a couple months, pull the motor, and pay cash to fix whatever the problem is. Getting out of debt sucks, but it'll feel great driving around in a beautiful 5-spd turbo wagon with a strong motor and no debt. Once I recover financially I'm going to do a bit of a custom tune to help make the system safer than stock, while probably adding a little bit of power. Good to have friends in the right places, I guess. Check out BtSSM (link in my sig). Even if you don't have an android phone it's worth buying an old one just to datalog. Edited November 20, 2015 by StkmltS My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted November 21, 2015 Author Share Posted November 21, 2015 I feel like I may be on to something here... I combined all of the data from 9 recent logs, trying to find some correlation between my misfire and anything else, and it's obvious that I'm missing data for quite a few values that I think should be coming from the MAF sensor. For those who datalog: Do you have data for any of these values? AFR = 11.2, 12.0, 12.8, 13.5, 14.3, 15.1, 15.9, 16.6, 17.4, 18.2, 19.0, 19.7, 20.5 My combined log has 85,537 rows of data, and none of them contain data for any of the above AFR values. The chart should explain why I'm asking. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
RayC Posted November 29, 2015 Share Posted November 29, 2015 I checked out the BtSSM, i'm definitely considering it. Got the motor put back together and installed in the car last night. You know that feeling, when it goes back together and starts right up? (after priming the oil, yes). I'm still smiling. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted November 29, 2015 Share Posted November 29, 2015 ^ Congrats man. I think it is a very wise decision to get that tool now to monitor your engine health from now on. Link to comment Share on other sites More sharing options...
StkmltS Posted December 1, 2015 Author Share Posted December 1, 2015 I'm putting in new TGV>head gaskets tonight and deleting the flappers while I'm in there. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted December 2, 2015 Author Share Posted December 2, 2015 Well, I got the intake manifold completely removed in only 1hr 31min, so that's a small victory. My wife came home earlier than I expected so car time was cut short and I only got one TGV partially gutted. The gaskets between the TGVs and heads showed no signs of leaking. So new gaskets probably won't fix my misfire (no big surprise). My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted December 2, 2015 Share Posted December 2, 2015 Are you just removing the flaps, or gutting the divider too? 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...
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