Hello Subie gurus, Its been a while since I last visited , but I want to thank those members who responded to my questions about a short block for an out of round cylinder/piston on my wife's 02 Legacy last year. The car now has 118K on it and still running strong despite the piston slap. As I said before I am not the greatest wrench especially when it comes to these newer cars with computers . Here is my latest problem with the Subie. Several weeks ago some lights were left on in the car which caused a complete drain of the battery. We were heading to town so I jumped it and while my wife was shopping in town after the 30 minute trip , I sat in the car and let it idle to make sure the battery got a sufficient charge. While I was sitting there the car was idling at about 700rpm and all of a sudden it shot up to 1100 or so like it idles when started up on a cold day. I timed it and this occured in cycles of about 22 seconds . Every 22 seconds the idle would shoot up to over 1000 rpm and then stay there for a few seconds and then go back down to normal of 700. Thats my guess from the dash tach. So the only thing I have tried is to disconnect the battery completely for a while to see if the Computer would reset itself to factory settings like it does in my 97 F-150 pickup. The Ford requires at least a 2 hour disconnect . Will the Subie do the same ? I only disconnected it for a few minutes as my wife was heading to town again yesterday. I am concerned because if one is not carefull to completely brake the car at stoplights it sometimes surges ahead a bit when the RPMs increase. Is there a fuse I can pull or something else I can unplug to make it stop this behavior. I can not afford a visit to the dealer so I want to try and fix it myself despite the fact that I havent a clue as what to do .Any ideas? Thanks in advance for your help
To quickly discharge the power in the car and reset the ECU, you could just disconnect the battery, and then hold down the brake pedal for about 30 seconds. After you hook the battery back up, it should be reset. I have no idea on the surging issue. I'm sure others will chime in.
You can also pull up the carpet under the front passenger's feet and simply unplug the ECU for a minute to reset it. Its easier for me than disconnecting my battery, lol. As for the surging, if you're ECU was recently reset (from the dead battery) it could be relearning some idle behavior. I wouldn't consider it too odd unless it continued after several days of driving. And then, I don't know.
its probably just the ac compressor kicking on, most ppl drive around with the defrost on not knowing it turns the AC on....This is probably just the 1st time you noticed it.
