Case Study: My Misfire Blues (Updated Logs) This will be a long read, as I am trying to provide as much history and data as I can. The first person to actually figure this out will get to name my first born child. Here goes... The car: '01 RS (125k miles) w/ '02 EJ205(WRX) (62k miles) w/ '03 WRX ECU The mods: Helix Uppipe, Invidia Downpipe, Fujitsubo RM01A Exhaust, STI Intercooler, K&N Intake More details: http://forums.nasioc.com/forums/showthread.php?t=1005133 The problem and its history: I got the car about 8 months ago from a friend. The guy he got it from was the one who had the swap done 2 years ago. Apparently it had thrown a misfire code once before my buddy got it, about a year ago. I think my buddy had only one thrown while he had it. Since I got it, the misfires have been gradually becoming more common. Its to the point now where the CEL will come on within a day or two of resetting the ECU. Probably 9 times out of 10 I get P301 (cylinder 1), but occasionally I'll get a mix of all other cylinders. (Tonight I got 301, 303 and 304) I have had no other codes thrown. Usually the CEL will popup during calm low throttle driving. What it feels like: I have never felt any problems at WOT, and the car pulls nice and hard. Occasionally there will be a rough idle. The main thing I feel is stumbling during low throttle, usually in the 2k - 3k rpm range. NOTE: this isn't consistent, there will be long periods of time where it feels absolutely fine. Sometimes the stumbling is random but often feels like a rhythmic hesitation. Basically loose some power, run normal, loose power, run normal, etc... in half second increments, and only if I leave the throttle in about the same place. What's been checked/changed: - Compression test at TopSpeed was fine. - No vacuum leaks. - A couple sets of OEM plugs. - New coilpack on Cyl #1. - Cleaned IACV. - New PCV valve. - New MAF. Here are a couple logs for ya: This was the 3rd gear pull tonight. About 30 seconds later I go the flashing CEL with 301,303,304. I think the flashing means more than 3% misfires over 1000 revolutions. Normally I don't get the flashing CEL. UPDATED: Now has the Air/Fuel #1 Learning % and Air/Fuel #1 Correction %, same run Code: Time RPM A/FLearn% A/FCor Throt MAF IgnTim MPH KnockCor Inj#1Duty PWDC IACV% AFR EGT Boost 0 2237 11.72 -8.59 18.43 12.32 28 27 0 8.59 3.14 40.5 14.47 698 -5.659 250 2290 11.72 0 100 37.27 31 27 5 16.12 15.69 41 21.71 698 0.29 500 2429 11.72 0 100 41.57 31 27 8 17.62 25.1 42 11.94 698 1.306 750 2331 11.72 0 100 43.35 28 27 8 18.4 37.65 44 12.06 707 2.031 1000 2543 11.72 0 100 49.53 27 27 8 21.16 50.2 45.5 11.83 698 2.757 1250 2578 10.94 0 100 53.09 24 28 8 22.55 62.75 47.5 11.6 707 3.627 1500 2655 9.38 0 100 57.64 23 28 9 24.35 75.29 51 11.48 707 4.643 1750 2767 8.59 0 100 65.39 21 30 9 27.75 75.69 59 11.48 707 5.804 2000 2879 7.03 0 100 74.06 19 32 9 30.09 72.94 68.5 11.6 707 7.255 2266 3024 6.25 0 100 84.9 18 32 9 35.48 72.94 79.5 11.37 716 8.851 2516 3121 5.47 0 100 97.33 16 34 9 41.95 72.94 81.5 11.25 725 10.447 2766 3255 5.47 0 100 110.22 14 34 8 48.61 72.55 86.5 11.25 734 12.333 3016 3395 4.69 0 100 116.38 13 37 8 53.6 72.55 90 11.6 743 13.204 3266 3549 3.91 0 100 123.34 12 37 8 57.55 72.55 93 11.83 752 13.494 3516 3716 3.91 0 100 131.69 13 40 7 61.84 72.55 93.5 11.83 770 13.784 3766 3862 3.13 0 100 137.17 14 40 7 64.26 72.16 93.5 11.94 788 14.075 4016 4080 1.56 0 100 140.71 16 43 8 67.02 71.76 93.5 12.17 815 13.784 4266 4162 1.56 0 100 146.44 15 43 8 71.03 71.76 93.5 12.29 824 13.784 4516 4350 1.56 0 100 156.82 14 46 7 77.02 71.76 93.5 13.09 851 14.075 4766 4486 1.56 0 100 166.24 15 46 8 83.25 65.88 93.5 12.98 878 14.8 5016 4629 1.56 0 100 172.78 16 50 9 86.91 54.12 93.5 12.75 896 14.8 5266 4808 1.56 0 100 173.47 17 50 9 89.23 49.41 94 12.52 914 13.784 5516 5003 1.56 0 100 179.37 18 53 8 92.86 49.41 94 12.4 932 13.349 5766 5119 1.56 0 100 183.21 20 57 8 93.92 49.41 94 12.06 941 12.914 6016 5271 1.56 0 100 190.99 20 57 8 96.7 47.84 94 12.52 959 13.059 6266 5427 1.56 0 100 194.33 22 61 8 98.41 44.31 94 12.06 977 12.769 6516 5597 1.56 0 100 194.33 23 61 7 99.1 42.75 94 12.06 986 12.333 6766 5774 1.56 0 100 200.29 21 64 7 101 37.25 94 12.63 995 12.333 7016 5896 1.56 0 100 201.43 21 64 6 100.63 31.76 94 12.86 1013 11.898 7266 5962 1.56 0 100 202.22 21 68 6 99.2 22.35 94 12.52 1013 11.318 7516 6127 1.56 0 100 203.01 22 68 6 99.34 15.69 94.5 12.75 1022 11.027 7766 6266 1.56 0 100 201.82 27 71 8 98.91 8.63 94.5 12.52 1031 10.447 8016 6432 1.56 0 100 201.03 29 71 8 98.8 1.57 94.5 12.06 1049 10.157 8266 6556 1.56 0 99.61 199.52 29 74 9 97.9 0 94.5 11.94 1058 10.012 8516 6550 1.56 0 0 196.93 30 74 0 0 0 95 12.75 1058 -7.835 8766 5971 3.13 0 0 20.6 12 76 0 0 0 95 16.08 1067 -9.867 9016 5601 3.91 0 0 21.2 12 76 0 0 0 95 24.23 1076 -9.867 9266 5095 4.69 0 0 20.69 12 78 0 0 0 85 23.89 1076 -10.012 9516 4635 5.47 0 0 17.29 12 79 0 0 0 73 24 1067 -10.157 9766 4162 6.25 0 0 10.89 12 79 0 0 0 95 23.89 1058 -10.302 10016 3774 7.03 0 0 8.28 12 78 0 0 0 54 24.23 1058 -10.302 This is cruising in 5th gear experiencing the rhythmic hesitation I described above. UPDATED: Now has the Air/Fuel #1 Learning %, Air/Fuel #3 Correction % and Air/Fuel #1 Correction %, same run Code: Time RPM A/FLearn% A/FCor#1% Throt MAF IgnTim MPH KnockCor InjDuty% PWDC IACV% A/FCor#3% AFR EGT Boost 0 3329 0 4.69 24.31 67.33 27 73 9 25.56 0 55 -1.56 16.54 995 3.918 250 3330 0 -2.34 23.92 69.16 28 73 9 22.02 0 55 -1.56 13.09 1004 3.918 500 3348 0 -3.13 23.92 68.22 28 74 9 22.86 0 55 -1.56 14.36 1013 3.773 750 3388 0 1.56 23.92 68.78 28 74 9 24.57 0 56 -1.56 13.9 1013 3.773 1000 3415 0 -4.69 23.92 68.59 28 75 9 22.58 0 56.5 -1.56 13.67 1022 3.773 1250 3440 0 5.47 23.92 68.97 28 75 9 24.95 0 56.5 -1.56 14.13 1022 3.773 1500 3454 0 -3.13 23.92 69.72 29 76 9 23.58 0 56 -1.56 14.24 1022 3.627 1750 3475 0 6.25 23.92 70.66 29 76 9 25.95 0 56 -2.34 13.44 1022 3.627 2000 3467 0 -2.34 23.53 70.47 29 77 9 22.93 0 56 -2.34 13.9 1031 3.627 2250 3487 0 2.34 23.53 70.47 29 78 9 24.54 0 56 -2.34 13.67 1031 3.482 2500 3536 0 -3.13 23.53 70.47 30 78 9 23.38 0 56.5 -2.34 14.01 1031 3.482 2750 3559 0 8.59 23.53 71.23 30 79 9 26.58 0 56 -2.34 14.81 1040 3.337 3016 3554 0 -2.34 23.53 71.23 30 79 9 22.75 0 56 -2.34 13.44 1040 3.337 3266 3607 0 4.69 23.53 71.8 30 80 9 26.16 0 56.5 -2.34 13.21 1040 3.337 3516 3594 0 -3.91 23.53 72.55 30 80 9 23 0 56.5 -2.34 13.44 1049 3.337 3766 3611 0 10.16 23.53 73.3 30 80 9 26.96 0 57.5 -2.34 15.62 1049 3.337 4016 3642 0 -1.56 23.53 73.68 29 80 9 24.09 0 58 -2.34 12.98 1049 3.337 4266 3642 0 1.56 23.53 74.43 30 81 9 26.42 0 57.5 -2.34 15.96 1049 3.192 4516 3705 0 -0.78 23.53 74.24 30 81 9 24.5 0 58.5 -2.34 12.98 1058 3.337 4766 3705 0 -7.03 23.53 75.75 30 81 9 24.5 0 58.5 -2.34 14.01 1058 3.192 5031 3759 0 7.81 23.53 75.94 30 81 9 28.07 0 59.5 -2.34 14.81 1058 3.192 5281 3763 -0.78 -7.81 0 12.21 37 83 0 5.62 0 65.5 -2.34 11.48 1058 -7.69 5531 3718 -0.78 -10.94 0 9.99 22 83 0 4.76 0 53 -1.56 14.13 1058 -9.431 5781 3722 0 0 0 5.08 12 83 0 0 0 45 -1.56 25.61 1058 -10.592 I am so tired of this.
Does it always seem to happen with throttle held in same place? Wondering if possible throttle position sensor.I have seen them(on toyotas) wear a bad spot in them in the part throttle(cruise) position.As far as the misfire I have had the #'s jump around(301,303,etc) due to just one cylinder misfiring.Again on toyotas the cel blinks when you are frying your convertors due to too much fuel from misfiring.I wish I had more experience with subees but the closest dealer is about an hour and they only had/have 2 techs.
Not always in the EXACT same spot, but close. But watching the logs, it seems the TPS readings will hold steady.
Already have actually. I didn't mention there's also a grounding kit on it, if that raises any concerns for anybody.
we need the long term and short term fuel trims at idle and cruise. Idle time being about 1~2 minutes of it when FULLY warmed up. Then do a normal cruise on level ground in 5th and like 60~70 mph for about 1 mile. LTFT and STFT also appears as AF learning #1 and AF correction #1. I was going to say do a ghetto grounding mod...but you've got a kit. pics of the kit? kthx.
5th gear cruising 1: http://okijuh.com/5thgearcruise1.txt 5th gear cruising 2: http://okijuh.com/5thgearcruise2.txt idling: http://okijuh.com/idle.txt ground kit: http://okijuh.com/groundkit1.jpg http://okijuh.com/groundkit2.jpg http://okijuh.com/groundkit3.jpg http://okijuh.com/groundkit4.jpg http://okijuh.com/groundkit5.jpg http://okijuh.com/groundkit6.jpg
picture #2: where is the huge factory ground at that goes to that 12mm bolt? two red grounding wires are going there as well as the siren bracket.
In 5th#2, your fuel trims are out of spec. However, your idle looks right on the edge of being 'ok' with those fuel trims. Its not bouncing, but anything more than 4% + or - in long term means a problem...I would venture to say you've got a leak somewhere. I'm pretty sure you dont have an injector issue. If you had a single, or more, injector issue...the short term trim would be all over the place, you'd have either an inconsistent idle, or consistently rough idle. 5th cruise#1 looks right on target for fuel tirms. So at this point you've either got some kind of leak, and/or an electrical issue. The leak may be dependent on load range. Same with the electrical problem. Its going to be something VERY simple, but not easy to find. I've ran into these things before. Each one is different.
I'd take the bracket off. The siren could be interfering with the ground return signals. SUBARUs are EXTREMELY sensitive to grounding.
The siren was moved there about two weeks ago. It was the only place I could find to relocate after installing the strut tower bar, but I'll give it a shot. What if I put a non-conductive spacer in between the bracket and the rest of the leads?
I had that thought...but on an OE car it would throw a P0340 quickly and usually before it starts to drive funny.
If any body is still paying attention to this thread, the car seems to be having a "good week." The CEL actually went away on its own and the stumbling/rhythmic hesitation has been at a minimum (but still present). Also, for the vacuum testing I was thinking about putting together something like this: http://forums.nasioc.com/forums/showthread.php?t=879900&highlight=vacuum+system+inlet+pressurize Anybody have any opinions on such a setup? Edit - Will, what do dealerships use for testing the vacuum system?
Thats what SS uses for pressure testing. Works well. Finds leaks in the inlet pipe, IC piping, etc. Vac leaks...well, depends on the tech. Smoke machines work good. But the old fashioned method of using brake/carb clean and spraying it around in the engine bay works too.
Tonights update: Ok, sprayed enough carb cleaner to kill several small children. No signs of any of it being consumed by the engine. Built myself one of the pressurizing caps for the inlet pipe. It turned out slightly ghetto-fied since the inlet take about a 2 1/8 or 2 1/4 inch diameter pipe and they don't really sell those at Lowes. So i used a good bit of thread tape wrapped around the end of a 2 inch diameter pipe to increase the diameter appropriately. It worked (for about 5 minutes until the tape gave way and the cap popped of the inlet pipe (scaring the shit out of me)). I don't think I even made it up to 10 PSI. At first I got the buzzing from the purge valve, so I disconnected the purge hose form the inlet pipe and capped the port. (Any chance that damaged the purge valve?) I heard nothing from the inlet pipe, IC hoses, etc. I did however hear some air leaking from the front left corner of the engine, in the region of the oil dipstick. At first I thought it was just the oil dipstick, but am pretty confident that that wasn't actually it... so what the hell was that? I'm not gonna give it another shot until I come up with something better than thread tape to get me cap to fit.
Manifold gasket leak. However, I've seen very large manifold leaks not cause the problems you are experiencing. But you still need to eliminate any and all leaks. I looked at the 5th gear log in the OP....I'm leaning more towards an electrical. You could try swapping out the cam and crank sensors for known good ones, just to eliminate that possibility. However, I'm still voting some other issue dealing with electronics or some strange leak.
How about this: Yesterday (snow day) I took the car out in the morning, ran great. I had to go to a funeral, during which the car sat out in the snow for about an hour and a half. Afterwards it started on the first crank, but had a lot of trouble keeping a steady RPM. Actually had to give it a little gas to prevent it from choking out a few times. I then had about a 25 minute ride in the funeral procession for rarely going past 1st or 2nd gear. For about the first 15 minutes the car ran absolutely horrible. Kept trying to choke out, serious stumbling. I basically had to keep it at high revs to keep going, and thus was basically burning the clutch the whole time. It eventually worked itself out and started running good. Stopped again for about 30 minutes in the snow. This time it cranked fine and ran great all the way home. Well it ran great, but started producing some really nasty smells about 15 minutes into this ride. I'm not really sure what it was. It was kinda like a burning rubber/plastic smell, but was so strong I just had to stop driving it for the rest of the day. I've been driving it around today without any smells or stumbling... so does this give anybody any ideas?
More questions, more info: Questions: 1) Any chance my problems could be related to the front O2 starting to flake out? 7) When exactly should the ECU switch between CL and OL fueling? Infos: I've started poring over the wiring, no biggies yet. I've been trying to do a lot more logging to catch some data when the car is being symptomatic. I've been able to get a few good logs of the "rhythmic hesitation." The AFR is bouncing between 16 and mid 13s, with the STFT bouncing right along with it. Throttle and MAF staying steady. I can typically get this to happen on small hills, so theres a small load. I've learned I can get this symptom to go away by giving it a lot more throttle. I also captured about a 3 second period where the AFR was steady up in the mid to upper 15s, again constant throttle, right around 20% and MAF appeared steady. I think the load was steady around 1.05. This was at about 80 mph, 3700 rpm on the highway. I think I was probably on a long steady hill for this one as well. Q8) Does anybody use anything else for graphing besides Excel that they could recommend?
Yes. Replace it if it appear to be the slightest bit flaky. Usually if the front A/F sensor is bad or going bad there will be codes for it, like a slow response code, a heater code, system too lean or system too rich (p0171/p0172). If its stock...there are delays built into the software that under certain parameters and time limits it stays in CL during boost conditions. After the timers expire and/or the parameters exceed what is specified, it will go to OL. At the time it goes OL, there is no longer any LT or ST fuel trimming. With CL delays zero'd out...when the Primary fuel map calls for 14.7:1 AFR, it will effectively trim ST and LT as if it were in CL...but the transition from CL to OL is effectively instant. During your logging: Was the MAP voltage/data stable as well?
Haven't seen any other codes yet, but I figure its worth a shot. As far as I remember it was, I'll double check when I get home tonight.
If you're looking into something electrical, I'd start with that turbo timer of yours. I've read lots of weird electrical issues stemming from them.
Ok, found something. Theres a leak in the up-pipe, right above where it attaches to the exhaust manifold, it's small but definitely there, could that be the source of these problems? It's actually a very strange leak, like a faulty weld or something. No its not the gasket...
What about a large leak in that area? Also, have now ruled out the front O2 sensor. Should have some more logs of actual misfires in action up later.
Yup, started doing that last night, for the engine harness at least. This weekend I'll probably get down to the ecu to see where the leads that should be going to my non-existent flash block stop and hopefully get that wired up...
Small and large UP leaks will not make misfires...only boost issues...aka not enough of it. yes! However it appears that you are already doing so. make sure you double and triple check everything. Did you check the MAP readings yet?
Well, I have so many logs no I can't remember which had the data I was talking about before, however I did catch another "ryhthmic hesitation" event tonight. I'm logging manifold relative pressure, is the adequate or do I need to get absolute pressure as well? About the attachments: The graph covers a few of the parameters during the rhythmic.txt file. You can obviously see the AFR, STFT and IDC bouncing up and down while all other data was pretty much steady. The wholelog.txt has the all of the data for that run (so the rythmic.txt and graph1.jpg are just a small portion of the wholelog.txt). It was during this run that I experienced the misfire code... however, the rhythmic stuff happened a good bit before the misfire stuff. In fact the misfire stuff was at the very end of the wholelog, and during this I wasn't getting the rhythmic hesitation, but sloppy/random stumbling, and strangely enough, the data looks pretty flat to me, though the STFT is pretty high throughout the end of the log... so have at it. http://okijuh.com/graph1.jpg http://okijuh.com/rhythmic.txt http://okijuh.com/wholelog.txt
those are some horrible short term fuel trims. It is adding about as much fuel as it can. Since you tested for intake leaks and didn't find anything major I am going to go with my first guess that you have an injector issue. Time to pull them out and get them cleaned/tested.
Something is seriously fucked. I'm going to agree with LF here and tell you to find some spare injectors,send them off to have tested and get cleaned/balanced...then install them. Use NEW ORINGS when installing the injectors.
Ok, let me ask this, could this also be a fuel pump flaking out? Also, if getting new injectors, might as well get higher flow since I'm getting injector duty cycles of 100% at full throttle/full boost, right? And with larger injectors do you need a tune?
what turbo do you have and what boost are you running? You should not be nearing 100% IDC on a stock turbo/injectors at anything under 18 psi boost.... Get a fuel pressure gauge and t it in after the fuel filter before hard fuel lines on the manifold. Record readings. Then go before the filter after the line comes out of the body.
Stock turbo (TD04?) and supposedly stock boost (13.3?), though I'm actual hitting high 14s. And the best I can tell the ecu has never been tuned...
I'm having trouble sourcing a fuel pressure gauge for testing, all i'm seeing is gauges you mount in the cabin, would one of those be good enough for my purposes? I don't plan on mounting it but, it would work for testing right?
You need a diagnostic one...something you'd find at autozone or similar. Just t it in, and secure it under the windshield wiper for qucik road tests. Thats what I do. Oryou can get fancy and 200mph-tape it to the windsheild.
If you've never done the fuel filter you may wat to throw that in as well. Sometimes god is good and it's the simple stuff. I fixed a fuel issue in a Ford 302 this way, after tearing half the system down. Good Luck
Ok now that I have one, pressure range am I looking for? Ok I looked at the Subaru service manual before posting and it says 41-46 psi with pressure regulator vacuum hose disconnected and and 33-38 connected... my gauge only goes up to 10 psi...
I think that part of what you are feeling as far as the oscillation of power is your boost fluctuating. If you have no tuning with an aftermarkt TBE, the computer is going to freak out a bit, especially when it gets colder. Maybe grab Enginuity and tune it a bit. Just a thought. As for the mis-fires, I have no clue, but you ARE going crazy lean under boost....13 afr at 14 psi is bad juju....especially at 4300+ rpm. This thing needs a serious tune. If you don't feel comfortable doing it yourself, take it to a tuner, but with that kind of stuff going on, it is a wonder the engine has not blown yet. I think that the lack of tuning could be a big part of your problem. Again, just what I am seeing from the data, but the fluctuating boost with high AFR's sounds to me like what I first saw when winter first hit, before I had tuned for the colder temps. I now have a summer and winter tune. The only real difference is the waste gate duty cycles. Also you might think about cleaning the MAF as well. I had some mild idle issues and cleaning it off helped smooth things out for me. Again, just my experiences, but they might help