bgambino Posted July 9, 2009 Share Posted July 9, 2009 in May I bought a beautiful 02 GT sedan with 70k on her (5 speed 2.5 non-turbo) craiglist BTW...and I'm still alive!!! Owner had just done the "60k" dealer servicing (looking at receipt, what a rip off!!! basically changed every fluid...replaced plugs, air filter, bal. 2 tires..."checked" this and that...for $500) Anyway...has been running very smooth As the warm weather approached I started hearing two things with the window open once in awhile... 1) a mini backfire? sound (or pop sound) when shifting from 1st to 2nd...or 2nd to 3rd. Exaust system is very quiet so I don't think it has anything to do with that. Threw a 0420 code 10 days ago...reset and is still gone (one of the o2's was replaced recently with OEM)...related to popping sound? who knows 2) I hear some valve pinging sometimes...like bad gas or out of time engine...yet it does not throw a knock sensor code. Does this engine need valve adjustments??? Is not bad gas because it has been going on for some time And I hate those little heat shield vibrations...they really piss me off...I want to rip them off...anyone have good solutions? Link to comment Share on other sites More sharing options...
bgambino Posted July 12, 2009 Author Share Posted July 12, 2009 "Unibrook" seemed to answer my question under the recent post entitled "Another misfire issue" He said: Have you ever changed your front 02 sensor? An old sensor will give you misfire cel. Pay careful attention to whether the car drives fine when cold, but then misfires when warmed up? (if so, this is how a bad front 02 sensor behaves.) If it misfires equally when the engine is cold and warm, then probably a diff sensor or diff issue. Actually pay attention to this, and take notes! I did this, and it led me to figure out it was my front 02 sensor that needed replacing....many thx to others on this list who pointed my nose in this direction. You can change your front 02 sensor in your driveway in an hour...just like changing a spark plug. Thanks Unibrook!! Now to my other question.....does a 02 2.5 Legacy GT non-turbo need the valves adjusted? I don't know why I hear valve ping under load sometimes (not bad gas)...anyone? If in fact my oxy sensor is bad causing the misfire, could it also cause occasional valve pinging? Link to comment Share on other sites More sharing options...
bgambino Posted July 17, 2009 Author Share Posted July 17, 2009 where are all my subaru prognosticators and soothsayers??? On vacation???? No one is attempting this one?? I'm shocked:slobber: I'm confused about the occasional valve pinging...shouldn't the knock sensor prevent this? If the knock sensor was not functioning...would'nt it throw a code? Link to comment Share on other sites More sharing options...
nipper Posted July 18, 2009 Share Posted July 18, 2009 WHAT! See now you wolke me up and reminded me that i am the only one home while everyone else is out enjoying themselvs. i need more freinds and to get out more woe is me oh thats right, this is not about me Anyway...... During hot weather some ping is not a bad thing. In modern engines this ping (usually being ignited by a hot plug) is not an issue. You can try a cooler spark plug. The knock sensor is there to try to ignite the mixture before it controls in an uncontrolled pattern. You can do a tuneup, and make sure your EGR valve is functioning properly. Dont forget to change the pcv valve. Valve adjustmnent is called for at 105,000 miles, and thats just an inspection. www.cars101.com will have maint scheduales and info on your car. Now let me go back to my lonely beer.....hrmm.... lonely... MORE BEER FOR ME! Link to comment Share on other sites More sharing options...
bgambino Posted July 19, 2009 Author Share Posted July 19, 2009 Thanks Nip...LOL I figured I could count on you It just got OEM plugs...maybe I should check if they are the right type (check the receipt) I hate pinging Nip...you must have done a valve adjustment no? Is there a procedure anywhere? And can you explain again what the knock sensor is for if not for valve ping Link to comment Share on other sites More sharing options...
nipper Posted July 19, 2009 Share Posted July 19, 2009 (edited) Thanks Nip...LOLI figured I could count on you It just got OEM plugs...maybe I should check if they are the right type (check the receipt) I hate pinging Nip...you must have done a valve adjustment no? Is there a procedure anywhere? And can you explain again what the knock sensor is for if not for valve ping i've never done a valve adjustment on Blu as he uses shims, and sometimes its just easier to pay someone (and i have a dirt driveway). Valve ping? You may have noisey valves, but ping is something different, as opposed to knock. Some ping you really need to learn to live with, because it's normal. Thats whay the make power amps for car stereos. knock senser is for engine knock, not ping. Knock is an uncontrolled explosion in the cylinder. The knock sensor advnaces the timing to ignite the mixture in a controleed fashion. This starts the flame front at the spark plug, as oppsed to it exploding off the head gasket, or a hot spot in the piston. Knock is very bad for HG's, and can if really bad destroy a piston. Yes you loose power when the knock sensor does this, but its better then destroying the engine. Usually it is only one cylinder or a few rpms till things retunr to normal. This is whay a bad KS can make the car perform poorly. If the senser is cracked or loose it may think that all that rattling is engine knock, as opsed to a failed sensor. Sometimes the sensor can pick up other things as knock, but never noisey valves, adn even that is rare. nipper nipper Edited July 19, 2009 by nipper Link to comment Share on other sites More sharing options...
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