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03 wrx misfire, rich afr
Posted 29 October 2013 - 06:46 PM
Posted 29 October 2013 - 06:56 PM
I'd say install the O2 sensor so the engine knows how to run. I'm guessing it's been in some sort of limp mode w/o the O2, hence being able to at least run. Guessing your plugs are ruined from overly lean or rich causing rough running now. Surprised you haven't leaned out and destroyed it yet. If it's a turbo'd engine with no O2 you should smack yourself....
Edited by Bushwick, 29 October 2013 - 06:57 PM.
Posted 29 October 2013 - 10:41 PM
Posted 30 October 2013 - 12:30 AM
If you converted it to a carb'd engine you wouldn't need the O2 as you can tune the carb- that's the only time I can think of where "no O2" applies. In your case, you should have paid $0.50 for a bung, or very least a flat nut and welded that in for your wideband instead of omitting the O2 for it as you probably ruined the cylinder walls and rings from overly rich, not to mention your cat is probably coated if you are running one. Wideband is a tuning tool and a way to detect potential trouble early, it's NOT a replacement for your O2 sensor. Of course the car is running like ****, the ecm can't read the exhaust and make proper adjustments. On a turbo'd engine the O2 is IMPERATIVE to controlling how the engine runs under boost. Your EGT were probably all over the place. Like I stated before, the car was probably running in a limp mode or a preset "tune" (it'll ignore readings from sensors and run on base settings) that kicks in when a major sensor fails but after a 1k miles I wouldn't be surprised if you really destroyed something. Real shame as it could have been prevented and now it'll be potentially costly to repair.
EDIT: Put the O2 back in, change the oil and put new plugs (gap as per recommended, not something ridiculous) in and see if it runs. If it runs, get a compression tester and see where each cyl is at. If it won't start, do a compression test anyways to see if something mechanical is wrong. Remember to reset the battery for a while so the ecm resets. Can try starting fluid after you've replaced the plugs and oil to see if it'll fire or not. If it doesn't fire, than either no spark, bad Crank Position Sensor, etc. If it fires then stalls, look at the fuel system.
Edited by Bushwick, 30 October 2013 - 12:51 AM.
Posted 30 October 2013 - 11:47 PM
Posted 31 October 2013 - 12:59 AM
Running too rich for too long can cause all sorts of issues both with sensors and the internals. Get that straightened out 1st or risk hefty repairs.
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