southsidescooby

Thanks for the clarification on the resistor placement. I just wanted to be absolutely sure as to the meaning and proper syntax of your instructions. Sometimes people's memeory tends to fade and details get dull. "Across" does generally mean in parallel with but I am not risking a $500 ECM on assumptions! The connectors involved on my current wiring print are T6 and T5/B19. I do not see connector E25 on this print. The wire for pin 4 is white and the wire for pin 3 is blue/white. I will do some further investigating this weekend and see how the car is actually wired. As for the Seafoam, I read the procedure for introducing it straight into the induction system. I will do this when I have the time. For now it was much easier to simply dump a can in at the last refueling! Best regards and many thanks.

The Subaru dealer told me that Subaru of America is not willing to do anything else to resolve my detonation and lean running issues. I am following advice and running some SeaFoam cleaner through the fuel system to see if this might help. I am really interested in trying the modification to "condition" the rear o2 sensor's output. You stated that the resistor was installed "across" the sensor output. I am looking at figure WI-90 of the engine wiring harness and see the four pins to the sensor. Pins 2&3 appear to be for the heater. Pins 1&4 appear to be the input/output for the ECM. Did you place the resister in parallel or in series with the shielded output(pin 4)? Or did you install it across pins 1&4? Please clarify as I am anxious to try this fix! Thanks again for the help in making this car run correctly!

I am certainly impressed with all these great responses! Blitz, if I might ask how did you arrive at that particular resistance value? This really makes me wonder if a software change did not occur between '02 and '03 Subaru model years. I would imagine the oxygen sensors are probably the same P/N for both years (front and rear respectively). I am definitely going to discuss this with my dealer (not the resister mod) and see if a software upgrade might be available. If not I will certainly try the sensor compensation trick. 99obw, I also considered a fuel/induction cleaning and/or additive but found it hard to grasp how those systems could be that contaminated considering the good fuel we generally get here in Georgia. I regularly use the Redline fuel additive which seems to keep things quite happy in my other cars. I have not tried those products you mentioned but am sure they perform well also. Cookie, I mentioned the knock sensor, MAP sensor, and 02 sensors to the head of the service department as possible culprits. He assured me that all these are functioning within tolerance. I have a mind to break out my maintenance manual and do some checking for myself. I just would like the repair to be on their nickel not mine! Again, I appreciate all the help and suggestions. I will certainly keep you all posted.

Thanks for the reply RallyKeith! The ECU was reset when I completed the 30K service and was adjusting the valve lash. The dealer flashed the ECU @ approximately 38K which was some 500 miles ago. When I drove the '03 Outback I noticed spark knock as well but it did not seem to be as noticeable as mine. I figure it must just be the way these cars are programmed regarding fuel management as they obviously live on the stoichiometric "edge" from what the plug insulators looked like after the first 30K miles or so. My car also used coolant when I first purchased it but the Bar's Leaks (The OEM variety, not the heavy duty type) I administered seems to have stopped that. I have a feeling this is the "cooling system conditioner" that Subaru is now recommending for these vehicles. I appluad Fuji Heavy Industries for extending the powertrain warranty on these cars...many of us will need it! I am still baffled by the apparent lack of off-idle power in this car. I don't see a difference in the two years unless it is a software issue. I actually thought of driving another '02 Outback and think this is an excellent idea. If it is of any consequence I am a mechanic(aircraft) by trade and have maintained my own cars for some 20 years now. These include Volvo, VW, Mazda, SAAB, Chevrolet, and Honda. This is my first Suby and hopefully not my last!

I own a 2002 Outback Legacy which I purchased used with 25K on the clock. What bothers me obout this vehicle is the almost constant spark knock under light/moderate acceleration. I have taken it to the dealer twice and they have reportedly done extensive testing on the car including real-time data logging. This information has also been extended to Subaru of America. They report nothing wrong with the car. At the advice of SOA, the dealer reflashed the timing control map in the ECU. This had little if no effect. I have noticed through experimentation over many months that premium fuel will supress the pinging almost completely and I have also reset the ECU by leaving the battery disconnected overnight. I am concerned that this will lead to early head gasket failure and other problems. Other things I have noticed are off-idle hesitation and inconsistent idle(intermittent). This car also accelerates like I am towing a boat or something. I just thought they all did this since it weighs in at over 3500 lbs. and has such a small displacement engine. I was really surprised when I drove an '03 Outback loaner from the dealer with 12K miles. That car responded like a completely different vehicle!!! Has anyone else experienced these problems (what I perceive as problems but the dealer tells me otherwise).