nlviands Posted February 16, 2009 Share Posted February 16, 2009 I just got this 1996 Legacy (2.2). It has a pretty bad stumble when accelerating. The check engin light is on and the code is p0325 - knock sensor 1 ckt malfuntion Bnk 1 or single sensor. I took the car to the local subaru dealer and they said that besides the knock sensor that there is a mis-fire on the #2 cylinder. They wanted more money to diagnose the problem but said that it was probably the exhaust valve guide coming loose and causing the misfire which susposedly is a known issue with these engines. I replaced the knock sensor today and I would say that the stumble is better but the car still isnt running right. I have now read in a few places that the knock sensor is supposed to be put back in same position. What if I dont know what the original position was. The threads on the bolt looked clean. What can I do? The subaru mechanic said that if the valve guide was coming free that the cylinder would have to be replaced. Does anyone have any suggestions on diagnosing this without spending a bunch of money at the dealer. Link to comment Share on other sites More sharing options...
johnceggleston Posted February 16, 2009 Share Posted February 16, 2009 I just got this 1996 Legacy (2.2). It has a pretty bad stumble when accelerating. The check engin light is on and the code is p0325 - knock sensor 1 ckt malfuntion Bnk 1 or single sensor. I took the car to the local subaru dealer and they said that besides the knock sensor that there is a mis-fire on the #2 cylinder. They wanted more money to diagnose the problem but said that it was probably the exhaust valve guide coming loose and causing the misfire which susposedly is a known issue with these engines. I replaced the knock sensor today and I would say that the stumble is better but the car still isnt running right. I have now read in a few places that the knock sensor is supposed to be put back in same position. What if I dont know what the original position was. The threads on the bolt looked clean. What can I do? The subaru mechanic said that if the valve guide was coming free that the cylinder would have to be replaced. Does anyone have any suggestions on diagnosing this without spending a bunch of money at the dealer. there is a great picture/diagram of how the knock sensor should be installed but i couldn't find it. someone should point you to that thread. it's all about the proper alignment / angle. as far as the 'bad' cylinder goes, i can't say it does not happen but it is rare. i'd bet against it. address the knock sensor first then with no codes attack what's left, if anything.. a compression test can tell you a lot. Link to comment Share on other sites More sharing options...
EVOthis Posted February 17, 2009 Share Posted February 17, 2009 well first...how many miles are on the car? +1^..i have seen a few threads here before about the knock sensor position...i believe the connector that is on the sensor is supposed to kind of be angled toward the P/S rear towards like bell housing but on angle like toward the flywheel inspection cover...i cant remember the torque spec but its not like a ridiculous amount so be careful...these knock sensors are prone to cracking on the underside of the sensor which is likely what caused it to fail...as said i would definately not immediately be throwing red flags at the head dropping a valve guide without further inspection of the "less intrusive"parts (spark plugs,wires,fuel injector etc...)...which i doubt they even did considering they wanted more cash for diag... Link to comment Share on other sites More sharing options...
davebugs Posted February 17, 2009 Share Posted February 17, 2009 I don't know where that excellent pic is either of the knock sensor wire. A lot of times you can cheat. The wire lays on the block and makes a 'cleaner' line where it was than the surrounding aluminum. IIR the torque spec is like 13lbs or something. Basically is just runs up under the throttle body where the connector is so I always thought it would be difficult to be too far off the approved path. I'm sure you can find the pic if you searched. Or perhaps a regular here remembers where it is and will be kind enough to post a link. Link to comment Share on other sites More sharing options...
nlviands Posted February 17, 2009 Author Share Posted February 17, 2009 (edited) well first...how many miles are on the car? +1^..i have seen a few threads here before about the knock sensor position...i believe the connector that is on the sensor is supposed to kind of be angled toward the P/S rear towards like bell housing but on angle like toward the flywheel inspection cover...i cant remember the torque spec but its not like a ridiculous amount so be careful...these knock sensors are prone to cracking on the underside of the sensor which is likely what caused it to fail...as said i would definately not immediately be throwing red flags at the head dropping a valve guide without further inspection of the "less intrusive"parts (spark plugs,wires,fuel injector etc...)...which i doubt they even did considering they wanted more cash for diag... The car has 146K miles. I doubt at this point that the position of the sensor is 100% the problem. The car still has a pretty bad stumble. So, if the dealership is just trying to make money on me and it isn't really a bad valve guide, what is causing the misfire? Drove the car today and the stumble is not noticable when the car is cold but definately shows up after engine has warmed up. I replaced the plugs, plug wires, changed oil. Edited February 18, 2009 by nlviands Link to comment Share on other sites More sharing options...
nlviands Posted February 21, 2009 Author Share Posted February 21, 2009 Well, after changing the knock sensor the CEL hasnt come back on. So, the BS from the dealer about a possible loose valve guide was exactly that, BS. The car still stumbles but from what I was reading I think it may be a transmission problem. I will open another thread Link to comment Share on other sites More sharing options...
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