AMileHighLGT Posted April 14, 2015 Share Posted April 14, 2015 If it is a burned valve, it would come and go with temperature as the block warms and cools. I have seen that before. I had a cracked ringland. It would pass compression testing it finally failed one and then a leakdown test confirmed it. I compression tested once I knew something was up. I had a cyl 4 misfire. It wouldn't log any misfires when cruising and accelerating. Only at idle. And even then there were some times it wouldn't at all. I understand why you're asking. And yes it is logical, but if you think what happens inside the cylinder walls, that's all pretty violent stuff going on. And when it comes to cars and car repairs always expect the unexpected. Link to comment Share on other sites More sharing options...
StkmltS Posted April 14, 2015 Author Share Posted April 14, 2015 After the car warms up you would think the issue would be consistent. What was the car doing that last 5 minutes? I assume you shut the car off when you got home. Rough start? Stutter? The last 5 minutes prior to turning it off was stop/go traffic with a couple red lights and stop signs. When I got home I turned it off a few seconds after completely stopping the car, the idle was smooth (but with a barely noticeable misfire). When I started it back up after dinner it was immediately idling rough. When I'm accelerating while the idle is acting up it does seem to stutter slightly at about 3k rpm. The soap is for keeping the IC clean. Though now I just pressure wash the entire engine with boiling industrial degreaser and only a light misting of soap on the IC for protection. Also running a garden hose through the throttle body is a great way to get that deep engine clean; forget Chemtool, Seafoam, etc... For future readers: His first tip, and possibly his second tip also, is why people sometimes say "you can't believe everything on the internet". If it is a burned valve, it would come and go with temperature as the block warms and cools. I have seen that before. I had a cracked ringland. It would pass compression testing it finally failed one and then a leakdown test confirmed it. I compression tested once I knew something was up. I had a cyl 4 misfire. It wouldn't log any misfires when cruising and accelerating. Only at idle. And even then there were some times it wouldn't at all. I understand why you're asking. And yes it is logical, but if you think what happens inside the cylinder walls, that's all pretty violent stuff going on. And when it comes to cars and car repairs always expect the unexpected. My issues don't seem to be correlated with engine temp at all. I've experienced smooth and rough idles in cold weather with both cold and warm starts, and I've experienced smooth and rough idles in warm weather with both cold and warm starts. As best as I can tell the engine temp has little to zero affect on the symptoms. When it's in a bad mood and idling rough it is always also idling low, like between 400-700 rpm. It's almost like the ECU isn't reading the idle properly. Don't get too excited just yet, because even when its idling properly the misfire is still present. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
AMileHighLGT Posted April 14, 2015 Share Posted April 14, 2015 The last 5 minutes prior to turning it off was stop/go traffic with a couple red lights and stop signs. When I got home I turned it off a few seconds after completely stopping the car, the idle was smooth (but with a barely noticeable misfire). When I started it back up after dinner it was immediately idling rough. When I'm accelerating while the idle is acting up it does seem to stutter slightly at about 3k rpm. For future readers: His first tip, and possibly his second tip also, is why people sometimes say "you can't believe everything on the internet". My issues don't seem to be correlated with engine temp at all. I've experienced smooth and rough idles in cold weather with both cold and warm starts, and I've experienced smooth and rough idles in warm weather with both cold and warm starts. As best as I can tell the engine temp has little to zero affect on the symptoms. When it's in a bad mood and idling rough it is always also idling low, like between 400-700 rpm. It's almost like the ECU isn't reading the idle properly. Don't get too excited just yet, because even when its idling properly the misfire is still present. You have a vacuum gauge? Link to comment Share on other sites More sharing options...
StkmltS Posted April 15, 2015 Author Share Posted April 15, 2015 Just the digital version via the torque app, so I know I'm not seeing everything that's going on in real-time. I know it's not as good as an AP, but I log everything via torque... should I dig through the data and look for something in the vacuum/boost data? My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted April 18, 2015 Author Share Posted April 18, 2015 Installed a vacuum/boost gauge today. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
GT_Dave Posted April 21, 2015 Share Posted April 21, 2015 My car seems to have the same symptoms yours does with the very erratic yet stubbornly persistent misfire. I've logged some data via the BtSsm app and it confirms what I feel, which is also what you describe; the misfires vary in frequency seemingly at random. I'm subscribing to this thread, hoping that I can learn from what you figure out with your car. Link to comment Share on other sites More sharing options...
StkmltS Posted April 28, 2015 Author Share Posted April 28, 2015 My car seems to have the same symptoms yours does with the very erratic yet stubbornly persistent misfire. I've logged some data via the BtSsm app and it confirms what I feel, which is also what you describe; the misfires vary in frequency seemingly at random. I'm subscribing to this thread, hoping that I can learn from what you figure out with your car. Good luck, hopefully you'll solve your problem quicker than I am. On our EJ255's are the bank1/bank2 camshaft position sensors interchangeable? My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted April 28, 2015 Share Posted April 28, 2015 Good luck, hopefully you'll solve your problem quicker than I am. On our EJ255's are the bank1/bank2 camshaft position sensors interchangeable? Looks like they are the same according to this diagram - see part #6 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 April 29, 2015 Author Share Posted April 29, 2015 Looks like they are the same according to this diagram - see part #6 I guess I should have looked it up before asking... thanks for the info. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted May 5, 2015 Author Share Posted May 5, 2015 (edited) My DD is back on the road so the LGT is back inside the garage patiently waiting for my attention. I still haven't done the leak-down test... after that I'll take off the intake manifold and try to locate my vacuum leak. Just a nugget of interesting info... the past few times that my CEL turned on was exactly between shifts, somewhere in the ballpark of 4.5-6k rpm (nowhere near idle). Edited May 5, 2015 by StkmltS My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
Diamonddice6 Posted May 13, 2015 Share Posted May 13, 2015 I have the same issue, it's been parked since March, it started when changed the spark plugs with Denso iridium, throwing codes p0303 and p0304, returned back to old spark plugs, recheck the gap, changed the spark plugs, new set of wires, change the ignition coil, clean the fuel injectors, check the pressure in fuel lines, change the throttle body, change the rear O2 sensor, finally I changed the MAF, forgot to mention that I changed the fuel filter too, we thought the cause was the fuel as the car was idling fine with fuel aditive till reached the point of nothing help...with all of that still have misfire on cylender 3 and 4, both didnt move...still didnt get the time to do a compression test...probably this week...I am thinking in draining the fuel tank and add a new fuel? if didnt help will take it to dealer... Link to comment Share on other sites More sharing options...
StkmltS Posted May 13, 2015 Author Share Posted May 13, 2015 I have the same issue, it's been parked since March, it started when changed the spark plugs with Denso iridium, throwing codes p0303 and p0304, returned back to old spark plugs, recheck the gap, changed the spark plugs, new set of wires, change the ignition coil, clean the fuel injectors, check the pressure in fuel lines, change the throttle body, change the rear O2 sensor, finally I changed the MAF, forgot to mention that I changed the fuel filter too, we thought the cause was the fuel as the car was idling fine with fuel aditive till reached the point of nothing help...with all of that still have misfire on cylender 3 and 4, both didnt move...still didnt get the time to do a compression test...probably this week...I am thinking in draining the fuel tank and add a new fuel? if didnt help will take it to dealer... Welcome to the fourm! That's really strange that it started when you changed spark plugs and it didn't go away when you put the old plugs back in. Maybe your problem has something to do with how they're sealing, not the actual plugs themselves. Have you inspected (and cleaned) your two camshaft position sensors and your crank position sensor? My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
Diamonddice6 Posted May 14, 2015 Share Posted May 14, 2015 Thank you. no I didnt clean them, usually I go with the codes that car throwing, i am so careful of not ruining something else, the spare parts are so expensive, do you yhink these sensors can cause misfire? Link to comment Share on other sites More sharing options...
OhNineGT Posted May 16, 2015 Share Posted May 16, 2015 I THINK I have similar issue. Here is my log of what has happend: 5/4/15- Bought car. 2 blocks off the lot check engine light, lack in power, and nasty noise from turbo. 5/5/15- P0021 & P0011 Result- Confirmed Bad Turbo 5/11/15- Changed Turbo, Coolant, and Oil/Filter NOTE: Oil was black and filter was tough to get off (Don't think they kept up with regular oil changes) Same Day- P0301, P0303, P0304 5/12/15- Changed Spark Plugs Same Day- P0301, P0304 (Got rid of misfire in bay 3). 5/15/15- Took into mechanic Supposedly they checked the injectors, coils, plugs, and MAF. Still no solution, they told me it must be internal. However, it doesn't lack power or have any "engine shakes" (For lack of a better term". My buddy is a tech for Volvo, went though the Nascar program in NC. I had him check it out at Volvo and he couldn't find anything either. He says the way that it drives, he is highly doubtful that it is internal. Just stumbled on this thread and it seems to be very similar. Let me know if you have thoughts on anything that you have learned in your process. P.S. your well documented process HAS helped me think through possibilities. I appreciate it! Link to comment Share on other sites More sharing options...
Diamonddice6 Posted May 16, 2015 Share Posted May 16, 2015 Tomorrow will drain the fuel from the tank and replace it with a super grade, two days a go I added heet to the fuel and car runs well, the codes disappeared...strange.. I know...lets see what wil happened and will update you guys. Link to comment Share on other sites More sharing options...
StkmltS Posted May 17, 2015 Author Share Posted May 17, 2015 I'm elbow-deep into doing my leakdown test and I just realized I need a 22mm socket to rotate the crank... Amen to having a Sears and Harbor Freight within a mile of my house! I'll post my leakdown results later tonight. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted May 18, 2015 Author Share Posted May 18, 2015 Post #1 updated with leakdown results. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
StkmltS Posted May 20, 2015 Author Share Posted May 20, 2015 bump for feedback on my leakdown results My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted May 20, 2015 Share Posted May 20, 2015 - Cyl 1: 13.0% (median 13) - Cyl 2: 22.4% (median 21.5) - Cyl 3: 13.6% (median 13.5) - Cyl 4: 20.6% (median 22) Like you suspect, cyls 2/4 seem like they aren't holding compression as well as they should be. If the misfire only happens when the engine is warm, my guess would be valve clearances have become too tight, and they should be inspected, replaced if necessary, and the clearances adjusted. If you're going to go that far, you may want to pop the pistons out to check the ringlands anyway (it's pretty easy if you've gone that far). Then you should know what you're dealing with. But it seems like pulling your engine is in your future 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 May 20, 2015 Author Share Posted May 20, 2015 Like you suspect, cyls 2/4 seem like they aren't holding compression as well as they should be. If the misfire only happens when the engine is warm, my guess would be valve clearances have become too tight, and they should be inspected, replaced if necessary, and the clearances adjusted. If you're going to go that far, you may want to pop the pistons out to check the ringlands anyway (it's pretty easy if you've gone that far). Then you should know what you're dealing with. But it seems like pulling your engine is in your future The misfire is always present. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted May 20, 2015 Share Posted May 20, 2015 The misfire is always present. Right. Still could be a toasted valve. It could be ringlands too, but usually you get high oil consumption with that, and observe smoke/blowby coming out of the oil fill tube when you remove the cap. Sorry if it's been covered, but you already tried swapping the following various items with another cylinder, but the problem didn't move? Injector, Coil, Plug 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 May 20, 2015 Author Share Posted May 20, 2015 Right. Still could be a toasted valve. It could be ringlands too, but usually you get high oil consumption with that, and observe smoke/blowby coming out of the oil fill tube when you remove the cap. Sorry if it's been covered, but you already tried swapping the following various items with another cylinder, but the problem didn't move? Injector, Coil, Plug Based on everything I've read online my oil consumption is very typical for this car/year/mileage. I've never seen smoke come out of the filler tube, but during the leakdown test that's where I heard the air escaping (for all cylinders). I've swapped the plugs, coils, and injectors, and I replaced the original IM gaskets with the new(er) part# gaskets. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
heiche Posted May 20, 2015 Share Posted May 20, 2015 dunno sounds like an internal issue causing the misfire (which pretty much is narrowed down to valves or ringlands) But can I back way up and ask when this started (at 97k miles) had any work been done to the car? Any mods at that time? 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 May 20, 2015 Author Share Posted May 20, 2015 I bought the car last June with about 96k miles on it, I'm the third owner. The previous owner said no mods other than window tinting, and carfax shows owner #1 was a company that had all regular service completed at Subaru stealerships. As far as I can tell everything has always been stock with the exception of wear-and-tear items. There aren't any odd holes in the interior indicating removed mounts/gauges, and all original engine bits/wiring are where they should be and look like they've never been touched. Other than a few LED bulbs and my new clutch (WRX setup) the car is bone stock. My DiySB rebuild Got Misfires? Link to comment Share on other sites More sharing options...
Diamonddice6 Posted May 30, 2015 Share Posted May 30, 2015 Four days ago, I changed the spark plugs #3 and 4, seafoam the engine with a half can...the results are amazing...car runs smooth and stable...i reset the codes of misfire and didnt have them back since, however i used the car for only 7 miles, probably should drivr it for longer distance and see if the problem has solved. Link to comment Share on other sites More sharing options...
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