mgiff3860 Posted September 30, 2005 Share Posted September 30, 2005 My 01 Outback H6 wagon has been at the dealer for 3 weeks with a frustrating engine problem. It has 46k miles. Purchased new The check engine light came on. At idle the engine was misfiring on 1,3,5, fuel injectors were replaced on those cylinders. Problem continues. Computer was pulled and sent to Subaru reinstalled and problem continues. Plugs were checked, leak down test preformed, data stream completed, problem continues. Now they think the valves are carboned. The dealer (who has been great!) is as frustrated as we are. I can't believe that a car that has this few a miles could burn valves. They have relaced all the fuel filters air filters and checked all the electrical connections. Still will not run smoothly. Anybody? Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted September 30, 2005 Share Posted September 30, 2005 My 01 Outback H6 wagon has been at the dealer for 3 weeks with a frustrating engine problem. It has 46k miles. Purchased new The check engine light came on. At idle the engine was misfiring on 1,3,5, fuel injectors were replaced on those cylinders. Problem continues. Computer was pulled and sent to Subaru reinstalled and problem continues. Plugs were checked, leak down test preformed, data stream completed, problem continues. Now they think the valves are carboned. The dealer (who has been great!) is as frustrated as we are. I can't believe that a car that has this few a miles could burn valves. They have relaced all the fuel filters air filters and checked all the electrical connections. Still will not run smoothly. Anybody? Well, your post is a little confusing. 'carboned' is not really the same thing as burned valves. And I'd expect the plugs to be somewhat diagnostic in their appearance for either of those 2 conditions - especially when compared to the 'good' plugs. You don't mention if they actually found any significant compressions differences, if they checked fuel pressure/delivery, if they checked the coil pack, found a vacuum leak, checked the odd side cam timing, etc. It's kinda difficult for us to help. Do you have another dealership you could take it to? I dunno Quote Link to comment Share on other sites More sharing options...
cookie Posted September 30, 2005 Share Posted September 30, 2005 Cleaning carbon is easy enough to try with a number of methods. Folks here swear by Seafoam. Does not really sound major, just irritating. Perhaps there is someone else around there who is better at diagnosis. I have not heard of many H6 problems at all, maybe because they are stil fairly new. Quote Link to comment Share on other sites More sharing options...
bulwnkl Posted September 30, 2005 Share Posted September 30, 2005 I can't be much help, but I'm sure interested in the resolution of the problem. If I was troubleshooting my XT6 and I lost 1 whole bank of the engine, I'd be looking for an electrical problem or a mechanical timing (timing belt) problem for that bank. Were fuel injectors the first thing they tried? As has been asked, what were the results of the compression and leak-down tests? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted September 30, 2005 Share Posted September 30, 2005 i doubt the valves are to blame. i would bet money that you service the valves in that head and nothing changes. sounds like a shot in the dark to me. what were the results of a compression test? misfire all on one side of the motor should point to something they have in common - cam, timing belt, ignition coil pack. could be as simple as the spark plug wires to that side of the motor as well - they could have been randomly damaged by something....mouse chewing them, who knows but i'd have them checked out, verify good spark on that side of the motor. Quote Link to comment Share on other sites More sharing options...
Meeky Moose Posted September 30, 2005 Share Posted September 30, 2005 i've seen a wrx with the pass side belt off about 4 teeth cause those same symptoms. and the compression was good on all 4 cylinders, it was just misfireing on 1 and 3... check the timing belts, it would be wierd if one did slip at that low mileage but it can happen.. Quote Link to comment Share on other sites More sharing options...
cookie Posted September 30, 2005 Share Posted September 30, 2005 If it was me I would probably switch the coil pack first as that is pretty easy, and then look at the belt. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted September 30, 2005 Share Posted September 30, 2005 WEll, that engine has a timing chain. But i feel your dealership is not good at troubleshooting. I'd be tempted to take to vehicle elsewhere. Quote Link to comment Share on other sites More sharing options...
cookie Posted September 30, 2005 Share Posted September 30, 2005 I do recall the chain now. I have seen a chain screw up but it is extremely rare. It would seem that a complete engine compression test would also find carbon. One set of cylinders would have more compression that the other side. A compression test should also find valves out of time as results would be different from one side to the other. Makes it look electrical to me. Quote Link to comment Share on other sites More sharing options...
mgiff3860 Posted September 30, 2005 Author Share Posted September 30, 2005 I can't be much help, but I'm sure interested in the resolution of the problem. If I was troubleshooting my XT6 and I lost 1 whole bank of the engine, I'd be looking for an electrical problem or a mechanical timing (timing belt) problem for that bank. Were fuel injectors the first thing they tried? As has been asked, what were the results of the compression and leak-down tests? Fuel injectors were the first thing done. It passed the leak down test. Compression was within specs. I used the term "burned" for the valves and that was incorrect. They think they are carboned. Also it has a timing chain. I was told if it was even one tooth off it would not start. Coil packs were checked and are reportedly ok. It is one bank that is running poorly. And it just went. No early miss firing or anything that would make you think it was about to die. Thanks for your reply. Quote Link to comment Share on other sites More sharing options...
friendly_jacek Posted September 30, 2005 Share Posted September 30, 2005 You can have chronic and diffucult to diagnose misfire codes from things as banal as dirty MAF sensor or vacuum leak. You just need a good diagnostician. Unfortunately, dealers are notorious on swaping parts only and not using brains. Again, did anyone check for vacuum leaks? With one side misfiring, it could be intake/gasket leaking. One should also look at the O2 sensors signals and fuel trims to see the patterns. Better yet, get yourself a good OBD2 scanner, download free subaru service manuals and read up on electronics. http://www.obdii.com/ is a good resource. I recommend BR-3 interface. My experience with both Subaru and Toyota dealers is that they brake more things than fix things. Quote Link to comment Share on other sites More sharing options...
cookie Posted September 30, 2005 Share Posted September 30, 2005 Three cylinders aren't likely to just carbon up all at once one day are they? One would get a bit bad and then the others would get worse.... If this all came on at once and affected three cylinders I would be concerned about a common component to all three cylinders. Injectors fail one at a time so I would not have changed those. Valves fail one at a time. This would lead me to the coil pack if they are all on one bank like my car. I have never even looked under the hood of an H6 so I don't know the layout. After the coil pack I would check the wires and connectors that control it and entirely replace the computer with another to test. Quote Link to comment Share on other sites More sharing options...
cookie Posted September 30, 2005 Share Posted September 30, 2005 but would a MAF problem only affect one bank? I have not had this situation, but I would expect it to hit both banks. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted September 30, 2005 Share Posted September 30, 2005 OK, I know I've offered wags before, but I had a thought that is, however, contingent the design of the H6. I wonder if a bad cam angle sensor could create a bank specific code like this? Does this engine have 2 of them? I dunno edit; after re-reading the original post, it seems the engine actually was running poorly correct? How did they determine it was 1-3-5 specific? codes, carbon on plugs? I doubt it's a cam angle sensor now. The ECU uses the cam angle sensor as a 'check' against the crank angle sensor. Did they check fuel pressure/output? I think the pressure regulator is on the end of one of the fuel rails - maybe there's probelm with fuel, just not injectors. Quote Link to comment Share on other sites More sharing options...
cookie Posted September 30, 2005 Share Posted September 30, 2005 it's not much help but my BMW has two cam sensors (DOHC). It would seem to make sense that Subaru might use two. Quote Link to comment Share on other sites More sharing options...
bulwnkl Posted September 30, 2005 Share Posted September 30, 2005 Call me crazy, but if the compression is in-spec and it passes the leakdown test, I don't think "carboned" valves is indicated. If there was carbon buildup on the valves, it could get to the point that the valves were not closing/sealing properly, but then it wouldn't pass the leakdown test, and quite possibly wouldn't pass the compression check. This is a simple posting and description, but from the conversation here as is, the dealership's troubleshooting is sure different from what seems logical to me. This still looks electrical to me. Testing a coil pack can be misleading. Zillions of Neons across the globe (okay, hundreds across the country) have good coil packs according to the test, but replacing them fixes misfires/poor running. Not saying that's it, just giving an example. Is there something about the 3-liter that is essentially different from the ER27 and EA82? If not, then being 1 tooth off on the timing mechanism will NOT prevent the car from starting, it just won't run well. Again, I'm not saying that's it, just that I don't know and it doesn't give me confidence in the troubleshooters. Quote Link to comment Share on other sites More sharing options...
Adnan Posted September 30, 2005 Share Posted September 30, 2005 Hi, A lot of good ideas have been expressed. On the subject of cam sensors, they are typically used as "single tooth" indicators, that is, their function is to tell the system whether the crank is between 0 and 360 degrees or 360 and 720 degrees. Being off a tooth or two opught not to make a difference. Depends on the design of the engine management system. A two-bank engine typically will have independent fuel rails for the injectors and independent fuel pressure regulators. If you go back to the basics of engine misfires, it is caused by one or more of fuel delivery, spark, air and timing. It appears that you have eliminated spark as a contributor. Timing is easy to check. The belt and the ECU are the possible culprits but you've checked the ECU. Have you pulled the timing covers to confirm timing? I'm guessing either a bad FPR on that bank or a check valve gone bonkers. Unlikely for a check valve to do that so FPR would be my suggestion. Easy enough to replace. Good luck! Regards, Adnan Quote Link to comment Share on other sites More sharing options...
Meeky Moose Posted October 1, 2005 Share Posted October 1, 2005 all else fails, make them give you a new car Quote Link to comment Share on other sites More sharing options...
mgiff3860 Posted October 2, 2005 Author Share Posted October 2, 2005 First; thank you for your input. I don't know if they have checked for any vacum leaks. The list of things they have done is long. They did check the crank shaft sensor and it was allegedly fine. I agree with the many that have said there must be a common problem that is affecting the cylinder bank. I doubt the fuel injectors were bad but they were replaced anyway. I/2 of the cost of those is all I am on the hook for. Subaru is picking up the rest. They swapped the computer out of ours into another 01 and put the other computer in ours. The other car ran fine and ours continued to miss fire with the other computer. Now for the latest. They are pulling the engine and replacing the right bank cylider head. The thought is the valve guides are cooked. The Subaru tech line has been guiding the diagnoses. They insist that it is something mecanical I have to believe it is electrical. After 5 subarus with 4 cyl engines that all lived past 100k with no problems, I think that the 6 is cursed. Give me my BMW 6 any day. Thanks again. Quote Link to comment Share on other sites More sharing options...
Setright Posted October 2, 2005 Share Posted October 2, 2005 Has anyone offered the idea of a leaking intake manifold gasket? That would hit one side only. Same for exhaust manifold - but that would usually be audible. Quote Link to comment Share on other sites More sharing options...
cookie Posted October 3, 2005 Share Posted October 3, 2005 they should have found a leaking manifold if they did the old spray ether trick, but who knows. Quote Link to comment Share on other sites More sharing options...
friendly_jacek Posted October 3, 2005 Share Posted October 3, 2005 Has anyone offered the idea of a leaking intake manifold gasket? That would hit one side only. Same for exhaust manifold - but that would usually be audible. I did, #11 above. Quote Link to comment Share on other sites More sharing options...
mgiff3860 Posted October 12, 2005 Author Share Posted October 12, 2005 Thank you for all your replies. After 4 weeks being in the shop I finally got it back yesterday and the verdict: It was a timing chain that had jumped a tooth on the right side. Quote Link to comment Share on other sites More sharing options...
nipper Posted October 12, 2005 Share Posted October 12, 2005 hrmmm thats the second h6 ive heard with a premature timing chain issue nipper Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted October 12, 2005 Share Posted October 12, 2005 Wow! I had that as one of my guesses in the second post, but it is of no comfort - my wife's OBW has the H6. And this is the second time someone's heard of it huh? I wonder if there are common, and avoidable, conditions that lead to this? thanx for keeping us informed, glad you're back on the road. Quote Link to comment Share on other sites More sharing options...
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