NonovUrbizniz Posted January 18, 2005 Share Posted January 18, 2005 I have an 05 legacy... it had a shot primary O2 sensor... I never got a CEL for it... That does not make sense to me... The dealer says... the primary O2 was reporting a constant voltage instead of the normal range... which resulted in the car over fueling itself... BUT the secondary O2 was functioning properly... so it would correct for the mis-read of the primary... my question is... Regardless of that shouldn't it still diagnoss the primary as bad and trip the CEL... the stealership is saying NO. Anyone in the know please feel free to enlighten me. Link to comment Share on other sites More sharing options...
devobuzz Posted January 18, 2005 Share Posted January 18, 2005 Well I'm not a tech but my car had a bad front O2 sensor after 30 miles of ownership. It tripped a a CEL P2097, which indicated the rear sensor was too rich. There was no code for the front sensor even though it was stuck reading a constant voltage like yours... Link to comment Share on other sites More sharing options...
Deer Killer Posted January 19, 2005 Share Posted January 19, 2005 http://www.legacygt.com/forums/showpost.php?p=91769&postcount=41 Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 19, 2005 Author Share Posted January 19, 2005 To Devo: So you had a bad front O2 and it tripped a cel. right? I realize it was one for the rear sensor... but still you got a check engine light right? to deer killer: Even with bad maps wouldn't the lumpiness be eliminated once the o2 is reading properly... after all it's basing it on the reading from the O2 right? Or are you saying that even in open loop it fuels improperly for the read? Because I picked up the car last night and it still runs lumpy. I'm gunna have to bite the bullet and take a look at it myself... I just didn't want to have to considering that's the whole reason I bought a new car... So I didn't have to work on it. Sucks too because my buddies shop is one of the state emissions testing centers but their dyno is only a 2 wheel... so I can't use it for my sub. Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 19, 2005 Author Share Posted January 19, 2005 I talked to a non-envolved subaru service dept. and he said that he has replaced O2's which fixed the problem and there was never a CEL... These were older models though. he didn't specify what engine. I still don't get it though... If the O2's sending a constant voltage the computer should instantly know there's something wrong. Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 19, 2005 Author Share Posted January 19, 2005 talked to the tech... he re-iterated what the other service guy says... occaisionaly they (O2's) are a small amount out of range and it doesn't trip the CEL. Link to comment Share on other sites More sharing options...
Goon3r Posted January 19, 2005 Share Posted January 19, 2005 When I de-catted my old WRX it took at least 2,000 miles before the 'cat below efficiency threshold' code appeared. So it would appear the CEL won't always trigger immediately. Link to comment Share on other sites More sharing options...
dustinw Posted January 19, 2005 Share Posted January 19, 2005 To Devo: Because I picked up the car last night and it still runs lumpy. If the car isn't working right, make them fix it. That's why we have warranties and lemon laws. Link to comment Share on other sites More sharing options...
devobuzz Posted January 19, 2005 Share Posted January 19, 2005 Yeah it tripped a CEL for the rear sensor even though the front was bad. Gas mileage was poor - around 15 MPG. I didn't notice any driveability problems because I just got the car and didn't know what it was "supposed" to feel like... Link to comment Share on other sites More sharing options...
Deer Killer Posted January 20, 2005 Share Posted January 20, 2005 to deer killer: Even with bad maps wouldn't the lumpiness be eliminated once the o2 is reading properly... after all it's basing it on the reading from the O2 right? Or are you saying that even in open loop it fuels improperly for the read?I'm just saying there was a lot of incompetence in the ECU programming department. And for the japanese this is very bad because: 1. Admitting there is a mistake means firing someone. 2. They don't want to fire anyone. 3. Releasing an update means it was not perfect. 4. Not being perfect is dishonorable. Maybe I'm just very bitter from doing business...... Link to comment Share on other sites More sharing options...
eamiller Posted January 20, 2005 Share Posted January 20, 2005 To Devo: So you had a bad front O2 and it tripped a cel. right? I realize it was one for the rear sensor... but still you got a check engine light right? to deer killer: Even with bad maps wouldn't the lumpiness be eliminated once the o2 is reading properly... after all it's basing it on the reading from the O2 right? Or are you saying that even in open loop it fuels improperly for the read? Because I picked up the car last night and it still runs lumpy. I'm gunna have to bite the bullet and take a look at it myself... I just didn't want to have to considering that's the whole reason I bought a new car... So I didn't have to work on it. Sucks too because my buddies shop is one of the state emissions testing centers but their dyno is only a 2 wheel... so I can't use it for my sub. As for the O2 tripping the CEL, usually the ECU has to notice a trend over time before it registers a CEL. There are diagnostic routines that run when certain parameters are met (engine temp, throttle position, etc.). Usually, the routines have to fail a certain number of times in a row before the CEL trips (unless the failure is gross). Also, the "lumpiness" you are referring to (possibly the notorious surging that has been discussed ad nauseum here), does it occur under full throttle? If so, your O2 sensor has nothing to do with it. Once the the throttle goes over a certain amount (40-60% usually), the ECU uses the fueling maps exclusively. It doesn't give a crap about what the O2 sensor says. In that case, it's due to the tune in the ECU from the factory(which is apparently remedied by the Accessport's tune). Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 20, 2005 Author Share Posted January 20, 2005 Alright... Thanks everyone for the helpful info... deer killer: Tell me about it... my dad and I are in shipping (I just started) and he deals almost exclusively with japanese... the company I just started working for does some work with them too... It gets to a comical (if it didn't affect your livelyhood) point. As far as the car... I'm gunna drive it for a couple of weeks before I drop it off again.. The tech I talked to was VERY helpful and answered all of my questions quickly... So either he's used to lying and giving the answer the person wants to hear or he knows what he's talking about... The only problem for me though is he said that he didn't notice a driveability problem ever... which I certainly did... the car is smoother now on the throttle when driving but the idle is still lumpy by my standard... He said that was normal.. ONE of the other bizarre problems I've noticed was the throttle hangs/slows down while dropping RPMS when you depress the clutch... Say I'm driving in first towards the end of a driveway... i get up to 3-4k rpm... I put in the clutch and leave it in first... the rpm's drop from 3-4k to 2-3k and then either hang there and hold... or slow down how fast they drop... HOWEVER... if I take it out of gear the rpms drop at a normal rate... He said that is due to a "stepped throttle control valve" which steps the throttle down... which if is true i don't even get why they would do that... it serves no benifit and it causes way excessive clutch wear if you just clutch in and clutch out in the same gear... Basically i've been getting the 'nightmare customer' treatment from the first day I went there... Should've bought elsewhere and I knew it at the time... but they F'd up when quoting me a price so I got the car for 21,400 instead of 22,700. (base model i wagon 5 speed no optional equip.). OHHHH and to top it off.. the 150 or so miles I've put on the car since I've picked it up, have had the worst milage yet... My computer average reads 18.6... when I dropped it off complaining about poor milage it was at like 22.4-24.?. I'm gunna give it a tank or two and see what the averages are. He also said he DID pull the plugs and look at them which I think was a bold face lie... but I'm not really sure I can prove it... I'm gunna check them myself to see what they look like... if they're fouled I'm gunna freak out. Link to comment Share on other sites More sharing options...
RobY Posted January 20, 2005 Share Posted January 20, 2005 good luck pulling the plugs... Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 20, 2005 Author Share Posted January 20, 2005 ^ Yeah I know... that's why I think he's lying about checking the plugs. Does anyone know the procedure... I've looked at it briefly and it seems to me you'd have to at LEAST lower the motor by loosening some motor mounts... but I could certainly imagine it being much worse than that. I gotta get a service manual. Link to comment Share on other sites More sharing options...
Xenonk Posted January 20, 2005 Share Posted January 20, 2005 uh, to let you all know, the rear 02 sensor is there to check if the cats are working properly, the front 02 is what the engine runs off from to advance or retard timing. The 05 GTs are drive-by-wire (electronic throttle control). The rpms will hang there for a moment so that you can shift smoother (it's a luxury thing). It doesnt wear out the clutch because it's the same as someone doing a manual rev match. And if you were to clutch in and clutch out of the same gear on a non-stepped motor type and NOT rev match, the car would jolt from engine braking and you would end up having to burn some of the clutch to get it to catch the difference in speed from the drivetrain vs. the engine speed. Reason why your car is having some ugly mileage is because you are probably still in the break-in stage. The car has not adapt the driving habits of the owner let alone that the ECU hasnt gotten around to advancing the timing to make some power out of your car. Take it on a long highway cruise/road trip.. you'll break 26 mpg off one tank. Also, be easy on the throttle, a little input goes on a long way (switch your car computer real-time mpg readout and watch how the mpg changes when you take a little off the throttle some and you'll see how the reading can go from 12mpg to 57mpg just by lifting the gas a little). Keefe Keefe Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 21, 2005 Author Share Posted January 21, 2005 ^ thanks for the advise/info... I have almost 9k miles on the car already and have made over 20 40mi trips on the highway watching the milage the whole way trying to keep the "current milage" high... that's when I recorded the all time high of 24.? MPG... Also keep in mind this is an I not a GT... I've also taken at least 6 trips that are 80% highway over 100mi. I'm sure I have to give it some time especially since he obviously reset the ECU... but unfortunately during the week I don't have time to drive anywhere but from home to work and work to home... Thanks for explaining the stepped throttle control... It's funny though because when it does do that it seems to me that the car bucks more (probobly due to me being used to driving a car where I just let the clutch absorb the variation in speeds) IE... I'm used to slowly letting out the clutch to let the engine self match to the tranny or occaisionaly rev-match... so when I let the clutch out it (the stepped throttle control) is reving higher than I am with the gas pedal... so it smoothly engages... but then bucks because I haven't matched the revs with the throttle yet. Will adjust driving habits accordingly... I'll give the mpg another couple of tanks to normalize... thanks for all the help. Link to comment Share on other sites More sharing options...
Xenonk Posted January 21, 2005 Share Posted January 21, 2005 Subaru did the stepped throttle control so that you dont have to burn out the clutch or wear out the release bearing and such. Just easy on, easy off on the clutch.. IE less time pushing on the clutch, the less wear the car has to go through. Keefe Keefe Link to comment Share on other sites More sharing options...
NonovUrbizniz Posted January 24, 2005 Author Share Posted January 24, 2005 ^ thanks, It does make sense now that I know it's there... and does increase drivabilty... although I still dis-like it... kinda like ABS... I know it's good for the majority... but I prefer to not have it. Link to comment Share on other sites More sharing options...
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