superman22x Posted January 24, 2011 Share Posted January 24, 2011 (edited) My car has been giving me some issues. It threw a CEL, then it cleared itself on the next tank of gas, and I never had a chance to get it read. Then the car lost a ton of power after putting in some bosch plugs. We replaced the Bosch plugs with NGK, gapped them properly, and put new wires in. Still was missing a ton of power. I replaced the knock sensor, pulled the ground off to reset the ECU and took it for a 20-30 minute drive, got it up to 70mph easily and it seemed to be running good again. Been going on short trips here and there to the ski hill and around town and lately the mileage is pretty bad. It's got most of the power back, but not quite all of it. And it's getting 15mpg. I was expecting at least 20mpg since the roads are always snowy here(3rd snowiest city in the country, AWD ftw!), it usually gets around 27 though. So not sure where to turn next. Don't know of any subaru dealers around here either and there is no CEL. There is a belt squeal when the car starts and sometimes it even starts a little hard, could be because it has been around 5* the last few days, but still, that's not too bad... I have been told it's possible it's because it's stuck in open loop mode? My friend is going to bring his code reader over in a few days and we are going to check for that, and see if we can find out what the last CEL was. One more thing, it's the non-turbo model, 107k miles on it, almost all highway. Edited January 24, 2011 by superman22x Quote Link to comment Share on other sites More sharing options...
ericem Posted January 24, 2011 Share Posted January 24, 2011 Sounds like maybe you need to replace the o2 sensor. Hopefully all the spark plugs are tight? As dumb as it sounds i have done it important to go snug, than 1/2 turn. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 24, 2011 Share Posted January 24, 2011 I use Bosch plugs with no issues, and good millage. I can't imagine the Bosch plugs as the source of your problem. Have you replaced the air cleaner, or at least looked at it to see how dirty it might be? Really important to see what code may be stored aboard the car. Maybe the 02 sensor is not right. A code pull will identify that. It is possible that you may have simply gotten a bad tank of gas. Maybe it had a little water mixed in the gas. Just my 2 cents worth. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 Yep, I torqued them down fairly well. How hard is it to do an O2 sensor change? I am away at school and it's cold out, and I don't have a garage or even a paved parking spot. I park on top of about 8" of packed snow... Another theory I have is the after market plug wires maybe? They aren't NGK, so think that could cause this problem? Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 I use Bosch plugs with no issues, and good millage. I can't imagine the Bosch plugs as the source of your problem. Have you replaced the air cleaner, or at least looked at it to see how dirty it might be? Really important to see what code may be stored aboard the car. Maybe the 02 sensor is not right. A code pull will identify that. It is possible that you may have simply gotten a bad tank of gas. Maybe it had a little water mixed in the gas. Just my 2 cents worth. They defenitally gave us some problems. We had the Bosch twin tip ones in that didn't require gapping. Weird plug. We replaced them with NGK and that made a night and day difference. Still wasn't quite right. I'm going to see if I can get the code pulled tonight. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 24, 2011 Share Posted January 24, 2011 Reading the code is a great place to start, let us know what that gives as there's a lot of things this could be. Did the CEL come on before or after any work was done to it? Appears like it was before? Aftermarket wires are notorious for causing issues. If the issues *started* as a result of replacing the plugs (it didn't exist before but existed afterwards) then I would guess it's still ignition related...so you might try reinstalling the wires, making sure they're dry and seated fully or getting Subaru wires. O2 sensors can degrade. At 107,000 miles you're due for a timing belt change if it hasn't been done yet. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 Reading the code is a great place to start, let us know what that gives as there's a lot of things this could be. Did the CEL come on before or after any work was done to it? Appears like it was before? Aftermarket wires are notorious for causing issues. If the issues *started* as a result of replacing the plugs (it didn't exist before but existed afterwards) then I would guess it's still ignition related...so you might try reinstalling the wires, making sure they're dry and seated fully or getting Subaru wires. O2 sensors can degrade. At 107,000 miles you're due for a timing belt change if it hasn't been done yet. I never threw the old wires away. I get out of class at noon tomorrow, so I think I will try putting them back on and take it for a 20 mile spin, see how she does. The CEL was before we did anything. Although, it would occasionally misfire on really humid days, but stopped once it was warmed up. Been doing that for a long time though, and only a few times a year. Yeah, the timing belt will be addressed soon enough... Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted January 24, 2011 Share Posted January 24, 2011 If you want that car to run right, you will stick with OEM wires, and NGK plugs. Same if you go change out the o2, stick with OEM (if you want the car to perform correctly) If you don't care, then go to autozone and put on the crappy aftermarket stuff. Lots of threads on here about the tune up topics. Subarus, because of the wasted spark design, are very picky when it comes to ignition. Please get a new Timing belt installed, or you will destroy your valves when it snaps. That "belt squeel" you hear at startup, could be the T belt slipping, or it could be the alternator belt. But for sure, you are due for the T belt, the next time you start it could just snap. Keep at it, but read up here before you just go throw on some parts from a autozone or oreilly, etc. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 If you want that car to run right, you will stick with OEM wires, and NGK plugs. Same if you go change out the o2, stick with OEM (if you want the car to perform correctly) If you don't care, then go to autozone and put on the crappy aftermarket stuff. Lots of threads on here about the tune up topics. Subarus, because of the wasted spark design, are very picky when it comes to ignition. Please get a new Timing belt installed, or you will destroy your valves when it snaps. That "belt squeel" you hear at startup, could be the T belt slipping, or it could be the alternator belt. But for sure, you are due for the T belt, the next time you start it could just snap. Keep at it, but read up here before you just go throw on some parts from a autozone or oreilly, etc. Yeah, I understand that now. I'm fairly certain it's just the accessories belt slipping. Would get some messed up vavles if the timing belt was slipping. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 (edited) Well, plugged the reader in and no codes came up. Timing was between 10 and 12. Oxygen sensor was at 2.8 I think for front bank sensor 1. The interesting reading was that the engine was at 48% load when it first started, about 5 minutes later, still at 33%. No codes for O2 or Cats, but it didn't get a chance to go through a full cycle. If there was a larger problem, it should have thrown a code right away according to my friend. He wasn't able to pull the old code though since I reset the ECU when I installed the knock sensor... derp. Oh, and based on the exhaust smell, she's running very rich. Edited January 24, 2011 by superman22x Quote Link to comment Share on other sites More sharing options...
ericem Posted January 24, 2011 Share Posted January 24, 2011 Sounds maybe like a MAF sensor issue now make sure all your vacuum hoses are hooked up properly! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 24, 2011 Share Posted January 24, 2011 right, timing belt definitely is not slipping. if it has issues when it's cold then that might suggest the O2 sensor isn't the culprit of the current issues since it's not used until operating temperature is reached. i guess i'm forgetting something because i thought O2 sensors varied between 0 and 1 and you've got 2.8? even if 2.8 is okay though i think O2 sensors can be "slow" and below par in terms of response time, which an oscilloscope may show. front O2's are generally maintenance items around 100k, so at that mileage I would personally just replace it since I'd plan on owning it another 100k and the original probably won't be accurate to then. but i can understand not wanting to replace it too. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 right, timing belt definitely is not slipping. if it has issues when it's cold then that might suggest the O2 sensor isn't the culprit of the current issues since it's not used until operating temperature is reached. i guess i'm forgetting something because i thought O2 sensors varied between 0 and 1 and you've got 2.8? even if 2.8 is okay though i think O2 sensors can be "slow" and below par in terms of response time, which an oscilloscope may show. front O2's are generally maintenance items around 100k, so at that mileage I would personally just replace it since I'd plan on owning it another 100k and the original probably won't be accurate to then. but i can understand not wanting to replace it too. Yeah, I was thinking about getting that done. But it shouldn't be causing the car to run rich at idle, so I think that can be ruled out. What would cause it to run rich at idle though? The high engine load at idle with belt squeal makes me think one of the accessories might have a bad pulley? Combine that with bad wires and the engine is pumping in more fuel to make up for the high load, but all the fuel isn't being burned causing a rich smelling gas. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 24, 2011 Author Share Posted January 24, 2011 If the MAF was failing, should it throw a code? I unplugged the MAF and tried starting it. I didn't take it out of park, but it idled exactly the same. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 25, 2011 Share Posted January 25, 2011 not sure about MAF/MAP but some sensors can fail without triggering a CEL. it's rare but it happens. i've seen issues with O2 sensor (once), TPS (once) and crank sensor (two or three times) cause no start or poor running without throwing a CEL. Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted January 25, 2011 Share Posted January 25, 2011 They defenitally gave us some problems. We had the Bosch twin tip ones in that didn't require gapping. Weird plug. We replaced them with NGK and that made a night and day difference. Still wasn't quite right. I'm going to see if I can get the code pulled tonight. I use the Bosch platinum with the single tip that doesn't require gapping. Like said, no problem. Let us know what you learned from code pulling. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 25, 2011 Author Share Posted January 25, 2011 I use the Bosch platinum with the single tip that doesn't require gapping. Like said, no problem. Let us know what you learned from code pulling. Nothing on the codes. Tomorrow I'm going to get some MAF cleaner and see what it does as well as change the wires back to the stock ones. Quote Link to comment Share on other sites More sharing options...
ericem Posted January 25, 2011 Share Posted January 25, 2011 Nothing on the codes. Tomorrow I'm going to get some MAF cleaner and see what it does as well as change the wires back to the stock ones. Probably going to work perfectly after you swap the wires. I suggest that before spraying the maf. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 25, 2011 Author Share Posted January 25, 2011 haha, you are a bit more optimistic than me... Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 25, 2011 Share Posted January 25, 2011 haha, you are a bit more optimistic than me...i know, really. does seem odd so far, but you'll get it. i think the hard part for readers (like us) is that the symptoms seem to have started when you changed the plugs, things like that usually aren't coincidence. the caveat to that is sometimes folks tend to be motivated to do something (like change plugs) if there's a hint of an issue...so maybe the issue was there or starting before you changed the plugs. could that be the case? (i guess you'd say you're not sure since you had a CEL at one point). GIVE THIS MAN A !*($#*&$! Check Engine Light! Quote Link to comment Share on other sites More sharing options...
logic23 Posted January 25, 2011 Share Posted January 25, 2011 Yeah I lean more toward the wires since it previously had missfire issues on humid days. I would stay away from spraying the maf. It is an expensive part to replace if you mess it up. Just do one change at a time. wires and o2 sensor would be at the top of the list followed by fuel injector cleaner. Bad gas could also be an issue. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 25, 2011 Author Share Posted January 25, 2011 i know, really. does seem odd so far, but you'll get it. i think the hard part for readers (like us) is that the symptoms seem to have started when you changed the plugs, things like that usually aren't coincidence. the caveat to that is sometimes folks tend to be motivated to do something (like change plugs) if there's a hint of an issue...so maybe the issue was there or starting before you changed the plugs. could that be the case? (i guess you'd say you're not sure since you had a CEL at one point). GIVE THIS MAN A !*($#*&$! Check Engine Light! Sprayed MAF cleaner and got 25mpg. Also put the old wires in but it didn't change when I did that much. Here's my theory. Got misfires when first running only when it was VERY humid out. So changed plugs and wires. Putting in the bosch plugs and it ran terrible. This caused the knock sensor to malfunction and pull timing. Put in NGK plugs. A bit better, but not 100%. Changed knock sensor, and it's quite a bit better but still running rich. At some point the MAF got dirty or maybe my dad or I even touched it. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 25, 2011 Author Share Posted January 25, 2011 I'm thinking of picking up seafoam next time I am in town and running that through just for ************s and giggles... I didn't want to half to give up on this, so I'm glad it's pretty much solved. Being a mechanical engineer and then having to take your own car to a shop... Doesn't work like that. lol Quote Link to comment Share on other sites More sharing options...
idosubaru Posted January 25, 2011 Share Posted January 25, 2011 Being a mechanical engineer and then having to take your own car to a shop... Doesn't work like that. lolthat's when i first started working on my soobs was when i was in college for engineering. that was purely financially motivated though, i couldn't afford paying someone to do it. now that i can pay for it i don't. Quote Link to comment Share on other sites More sharing options...
superman22x Posted January 25, 2011 Author Share Posted January 25, 2011 that's when i first started working on my soobs was when i was in college for engineering. that was purely financially motivated though, i couldn't afford paying someone to do it. now that i can pay for it i don't. Haha, I'm working at GM this summer, I probably won't have the motivation to work on my own projects after work, lol. I'm a Ford guy at heart(I own a Ranger and a 93 Mustang), work for GM, and am currently driving my dads Subaru, lol. The only foreign car I drive gives me tons of problems... haha. Quote Link to comment Share on other sites More sharing options...
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