iayers Posted December 21, 2011 Share Posted December 21, 2011 99 OBW 2.5, 200k I'm getting a very rough idle & rough engine performance at all RPM's. ALL cylinders are misfiring. The car shakes pretty good and CEL flashes at idle. Replaced plugs, wires, and igniter/coil (all OEM, NGK, as recommended). Did not improve whatsoever. The car has been throwing P0420. I ran the car with the O2 sensor unplugged then plugged. No difference in performance. Smells like fuel when running. Been running fuel injector cleaner regularly. Recently Seafoamed the engine through brake booster. There are no exhaust leaks. What should I do next in the line of fixes? Given what I did, what does this sound like? Timing belt? Valves? Cat? Fuel? What would a good Subaru mechanic know to do on this? I will probably need to take it to a guy to check timing, compression, etc. Any help appreciated. Thanks guys. Or, direct to another relevant post? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 21, 2011 Share Posted December 21, 2011 My vote is for burnt exhaust valve. Check compression to confirm. GD Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 21, 2011 Share Posted December 21, 2011 Multiple cylinder misfires... could be jumped timing belt. The P0420 is probably just showing because there is raw fuel in the exhaust. If allowed to run like that for an extended period of time damage can be done to the catalytic converters so it would be wise to not drive the car until you get the problem resolved. Are you in Charlottesville, VA? I could probably look at it for you this week if you want. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 21, 2011 Share Posted December 21, 2011 Multiple cylinder misfires... could be jumped timing belt. Often mentioned on here but I've never actually seen it happen when not accompanied by other severe issues and noises - I've seen it happen once on an EJ22 where the water pump completely seized. That's the only one I've witnessed where it actually skipped without breaking. I've seen three times as many burnt exhaust valves from not doing the 105k valve shim adjustment. They run like poo and give all kinds of misfire codes when you blow holes in the exhaust valves. GD Link to comment Share on other sites More sharing options...
johnceggleston Posted December 21, 2011 Share Posted December 21, 2011 you have the 2 most likely causes above. do the compression test, either one or more cylinders will be bad due to burnt valves or 2 cylinders will on the same side will be bad due to the timing being off, jump t-belt. then check the timing belt. it is due at 210k miles or 105k after the last change. Link to comment Share on other sites More sharing options...
iayers Posted December 21, 2011 Author Share Posted December 21, 2011 I've seen three times as many burnt exhaust valves from not doing the 105k valve shim adjustment. They run like poo and give all kinds of misfire codes when you blow holes in the exhaust valves. GD If one valve burns, can this cause other cylinders to misfire, or is it possible that multiple are burning out. The problem has gradually gotten worse over last months. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted December 21, 2011 Share Posted December 21, 2011 Does it run any differently after it warms up? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 21, 2011 Share Posted December 21, 2011 The problem has gradually gotten worse over last months. Very important clue there. That's the symtoms of a burnt valve. Depending on driving habits and mileage it can take anywhere from a couple weeks to several months to develop as the cylinder loses more and more pressure from the expanding hole in the valve. The misfire's don't always tell the whole story - the ECU isn't perfect at determining which cylinder a misfire has occured on because it uses a heuristic based on crank angle sensor input - it tries to determine a misfire from the speed changes of the crank durring a single revolution. If a misfire occurs multiple times in the same cylinder durring a specified interval then it will set the CEL flashing to alert the driver and attempt to avoid catalytic converter damage from excessive unburned fuel. I had this happen once due to a loose camshaft pulley bolt (owner did his own HG's while unemployed). It chewed out the locator notch in the drive end of the camshaft and advanced the intake valve timing by about 30 degree's. Also got worse over a period of time. Strange thing in that scenario was that the compression was too *high* on the passenger bank because of the advanced intake valve opening. GD Link to comment Share on other sites More sharing options...
bobolinko Posted December 21, 2011 Share Posted December 21, 2011 99 OBW 2.5, 200k I'm getting a very rough idle & rough engine performance at all RPM's. ALL cylinders are misfiring. What should I do next in the line of fixes? Given what I did, what does this sound like? QUOTE] Have you tried cleaning the MAF sensor and the O2 Sensor ? My motor had the same scenario (random cyl misfires at all RPM ranges) I cleaned those sensors and if you have an IAT sensor, clean it too. Never had the symptoms again! cost of the carb cleaning fluid - $4.89 good Luck! Aloha From Hawaii! Link to comment Share on other sites More sharing options...
iayers Posted December 21, 2011 Author Share Posted December 21, 2011 Does it run any differently after it warms up? Nope, runs same cold as hot. Guess it's time for a compression test. Link to comment Share on other sites More sharing options...
iayers Posted December 21, 2011 Author Share Posted December 21, 2011 Very important clue there. That's the symtoms of a burnt valve. Depending on driving habits and mileage it can take anywhere from a couple weeks to several months to develop as the cylinder loses more and more pressure from the expanding hole in the valve. GD, how rapidly can these thing degrade? Is there the possibility of rapid failure? Before I can fix this, I am planning on doing 500mi of holiday highway driving. Can anything be added to the oil or fuel to protect it? How do I know it's BAD?? Link to comment Share on other sites More sharing options...
Fairtax4me Posted December 22, 2011 Share Posted December 22, 2011 It's already bad. It was bad when it started misfirIng. I would very strongly recommend you rent a car for your trip. With raw fuel being poured into the exhaust system the catalytic converters will get extremely hot and possibly catch on fire. Best case they will just plug up and cause the engine to bog down so much you can't drive the car anywhere. Link to comment Share on other sites More sharing options...
Caboobaroo Posted December 22, 2011 Share Posted December 22, 2011 Does it have any other codes stored or just the P0420 code? If not, its a good possiblility all the cleaners you ran through it could have caused one or both cats to collapse. Just some food for thought. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 22, 2011 Share Posted December 22, 2011 I would not drive it 500 miles with a flashing CEL. That's an indication of a really serious misfire condition and you could end up stranded. GD Link to comment Share on other sites More sharing options...
bobolinko Posted December 23, 2011 Share Posted December 23, 2011 I would not drive it 500 miles with a flashing CEL. That's an indication of a really serious misfire condition and you could end D The CEL is a "flag" indication that there is something "not right" with the engine, thus the term Engine Check Light... If the motor misses for 3 firings, it throws a code to the ecu to indicate a POSSIBLE problem and the problem can be analysed with looking up the code. The code usually stays there untill cleared, or 13 or so restarts with no recurrence, then it would clear by itself. If it is a misfire, it could simply have been a moisture droplet that was in the fuel system, and not a serious problem at all. If after clearing the code and it IMMEDIATELY re-appears, then, I might be a little more concerned. otherwise, I would not. If it came on when I was 20 miles into a 500 mile trip, I would keep an ear to the motor's smootheness, but would not scuttle the trip unless the engine runs really bad. I have found someimes, while the motor is missing, turning off (reboot the ECU) the engine for a few seconds and restarting corrects the miss, but the ECL has to be reset with a tool. I installed a scanguage in my car, and it easily can analyze and clear all the CEL notifications. Ha ha maybe this now will be more to think about for you .... There are inexpensive OBD-II (OBD2) check tools that might be useful for you ... Got mine from E-Bay. Check that it's usable on your vehicle before you purchase. I spent $35 on mine, just for peace of mind. Aloha ! Link to comment Share on other sites More sharing options...
GeneralDisorder Posted December 23, 2011 Share Posted December 23, 2011 That's all well and good - but the CEL only *flashes continuously* for one reason - continuous misfiring. That means excessive unburned fuel in the exhaust - which means RED HOT cat's (trust me I've seen it numerous times). This is a fire hazard and the car SHOULD NOT be driven. GD Link to comment Share on other sites More sharing options...
Ricearu Posted December 23, 2011 Share Posted December 23, 2011 I would rent a car. I would run a compression test also. Running for a LONG time on 3 cylinders is abusive to the crankshaft also. I wouldn't do it. Catalytic converters catch fire over crap like that. Bare minimum, if I had to destroy my car to drive it to see family, run the compression test and unplug the injector from the dead cylinder to avoid the catalytic converter overheat. You can still make it worse by driving it. Link to comment Share on other sites More sharing options...
nipper Posted December 24, 2011 Share Posted December 24, 2011 When was the last time the timing belt was changed and what was changed with it? Depending upon the code if it fixes itself from time to time it may not stay in memory. I would get codes read, see what it is, and if you do not want to go through the pain of a compression test right now (holidays and all) get a vacuum gauge on the car and it will tell you quite a lot. Link to comment Share on other sites More sharing options...
Mugs Posted December 24, 2011 Share Posted December 24, 2011 I have seen this this situation from an inexperienced at home timing belt job..They did not have the tools to properly torque down the crank pulley. Pulley loosened up just enough to allow the crank gear to start hogging out the key way on the crank. Which also hogged out the key way on the crank pulley. So this moved the crank gear out of spec, thus causing multiple miss fires on on the cylinders because it was out of time all together. Unfortunately the crank was so hogged out the engine had to be replaced. I remember looking at the crank pulley when I first started diaging it and thought to myself...man that thing is sure bouncing around a lot...it was way out of round/balance...you may want to check that. Crank pulley being what your drive belts for the alternator A/C power steering are hooked up to. Link to comment Share on other sites More sharing options...
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