Lawsonmh15 Posted June 26, 2007 Share Posted June 26, 2007 Oh I know, it's been awhile. Nonetheless, I've got a new weird one for you folks. Lately we've had 90+ degree days so last week I thought, "backsweat isn't so neat. I should turn on the AC". So I did. Then I noticed I had a CEL. Hmmm, everything seems to be OK with the exception of the horrible performance I get with the AC on. A day or so went by. The weather cooled off. The CEL disappears. Super. One less stress. Gets hot, at some point the AC goes on, as does the CEL. For the last day or two the CEL stayed on WITHOUT the AC on so I went to checker and had the code pulled. PO325. Shize!!! No biggie on a 2.2, no clue where to find it the knock sensor on a 2.5. Did some threadin' and found that people have attributed false positives to bad gas. Cleared the CEL, drove to checker, bought some seafoam, drove home, no code. SeaFoam at this point was just for good measure. What I'm wondering, is it possible that my F'd up AC could be causing my false positive??? Would it be more likely that I may have gotten a batch of freshly filled gas = BAD? Either way, as long It doesn't come back I'm cool but would like to get some of the Vets' takes on this (that's you nipper). Anyone gone headlong into replacing the Knock sensor, did it, then had it throw a 325 shortly thereafter? I know that is has to some people but very few followed up with the resolutions. I read in one thread that a dude started filling with 93 and that alone seemed to resolve the problem but really. Considering all I've read about neglecting knock sensors results in catastrophic engine failure, I don't want to lull myself into "false sensor" security. (it's a pun) EDIT: Found a pic. Looks like I need to get a long extention and go between the throttle cables and TB for a straight shot but going to try to save the $100 until I KNOW that the problem can't be solved by a $7 bottle of Sea Foam and wishful thinking. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 26, 2007 Share Posted June 26, 2007 Usually a knock sensro code means the knock sesnor is dying. Now if your AC is self destructing and making god awful screaching knocking noises, well yes it may confuse the knock sensor. Bad gas is a rarity these days, but it happens. ONe option is to unbolt (do not disconnect) the knock sensor and see what happens. i bet you need a new knock sensor. nipper Quote Link to comment Share on other sites More sharing options...
Lawsonmh15 Posted June 27, 2007 Author Share Posted June 27, 2007 Usually a knock sensro code means the knock sesnor is dying. Now if your AC is self destructing and making god awful screaching knocking noises, well yes it may confuse the knock sensor. Bad gas is a rarity these days, but it happens. ONe option is to unbolt (do not disconnect) the knock sensor and see what happens. i bet you need a new knock sensor. nipper Not Exactly what I was hoping to hear. Nonetheless, going to hope I don't see it come back. Until I freak out about the what-ifs and money flows nicely. Quote Link to comment Share on other sites More sharing options...
biglittledog Posted June 27, 2007 Share Posted June 27, 2007 Usually a knock sensro code means the knock sesnor is dying... ONe option is to unbolt (do not disconnect) the knock sensor and see what happens. i bet you need a new knock sensor. nipper I replaced one a year ago on our 2000 Forester and its in almost the same place on the engine block, there's just some other misc. crap around/above it. Our car was throwing the same code. Since your in town...I got my knock sensor at Checker to save money. If you order on line and pick it up in the store you save some more cash. Here's a link but I'm not sure exactly what you're driving: http://www.partsamerica.com/ProductDetail.aspx?MfrCode=NIE&MfrPartNumber=WA1751&PartType=412&PTSet=A 71 bucks and you can probably find it online even cheaper. If you need tools cheap, you can go to Harbor Freight. Buy their extensions or the 13.99 "wobble extensions" set. cheap torque wrench (better than guessing...) 20 bucks or borrow from neighbor down the street since you probably won't use it much if your just doing maintenance stuff only. You know the guy that's always revving his Camaro up in the driveway Sunday mornings. Go ask him, he'll have one and will probably end up helping you swap the sensor. PS- Harbor Freight tools are cheap but if you use them infrequently maybe that's for you. I'm a Craftsman wrench guy and figure I'll use most basic tools for the rest of my life so it's an investment plus I can't afford to drop the cash on Snap-On stuff although I'd love to. I'd also normally buy OEM for sensors and thus a Bosch unit but the knock sensors suck and fail no matter what... Quote Link to comment Share on other sites More sharing options...
Lawsonmh15 Posted June 27, 2007 Author Share Posted June 27, 2007 I replaced one a year ago on our 2000 Forester and its in almost the same place on the engine block, there's just some other misc. crap around/above it. Our car was throwing the same code. Since your in town...I got my knock sensor at Checker to save money. If you order on line and pick it up in the store you save some more cash. Here's a link but I'm not sure exactly what you're driving: http://www.partsamerica.com/ProductDetail.aspx?MfrCode=NIE&MfrPartNumber=WA1751&PartType=412&PTSet=A 71 bucks and you can probably find it online even cheaper. If you need tools cheap, you can go to Harbor Freight. Buy their extensions or the 13.99 "wobble extensions" set. cheap torque wrench (better than guessing...) 20 bucks or borrow from neighbor down the street since you probably won't use it much if your just doing maintenance stuff only. You know the guy that's always revving his Camaro up in the driveway Sunday mornings. Go ask him, he'll have one and will probably end up helping you swap the sensor. PS- Harbor Freight tools are cheap but if you use them infrequently maybe that's for you. I'm a Craftsman wrench guy and figure I'll use most basic tools for the rest of my life so it's an investment plus I can't afford to drop the cash on Snap-On stuff although I'd love to. I'd also normally buy OEM for sensors and thus a Bosch unit but the knock sensors suck and fail no matter what... I hear you on the harbor freight beauty. When the woodruff key on my crankshaft went, I refused to remove the radiator so I went to harbor freight which, oddly enough, was the only place I could find around town that had 60 degree offset wrenches so I could do work on the tensioner pulley. I think I spent $30 on a full set of metrics. All are still in working order. Quote Link to comment Share on other sites More sharing options...
Lawsonmh15 Posted August 12, 2007 Author Share Posted August 12, 2007 Well, it seems as though the code gets thrown when the engine gets hot. If I disconnect the batt. ground, discharge all capacitance by holding down the break pedal, then let it sit for about 15 minutes, the code is cleared until I'm in stop and go in 100+(in sun). Thinking it may be the plugs and a need to get a real FLUSH done on the radiator. Anyone deal with something similar? I pulled the knock sensor and the casing is fine with very little corrosion on the sensor. Seems strange. Quote Link to comment Share on other sites More sharing options...
nipper Posted August 12, 2007 Share Posted August 12, 2007 plugs can cause ping. You may be getting the knock sensor code because no matter what the knock sesnor does it cant get rid of the ping. How old are they? nipper Quote Link to comment Share on other sites More sharing options...
avk Posted August 12, 2007 Share Posted August 12, 2007 Knock sensor is one of those items that chain stores sell for more than dealer list price. Quote Link to comment Share on other sites More sharing options...
Lawsonmh15 Posted August 12, 2007 Author Share Posted August 12, 2007 plugs can cause ping. You may be getting the knock sensor code because no matter what the knock sesnor does it cant get rid of the ping. How old are they? nipper A couple years. Probably 40-50k miles. Hate to say it, but have also been using 85 because of the ridiculous oil prices. Just doesn't make sense to pull and clean considering on the 2.5 it's such a momentus pain in the rump roast to pull the plugs. Quote Link to comment Share on other sites More sharing options...
OB99W Posted August 12, 2007 Share Posted August 12, 2007 [...]Hate to say it, but have also been using 85 because of the ridiculous oil prices.[...]No matter how well the knock sensor is working, the ECU can only retard timing just so much; the combination of temps at 100+ and 85-octane gas is likely to result in the condition you're experiencing. In fact, if the ignition timing is being retarded enough, the reduction in efficiency might offset any cost savings of the lower-octane gas. Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted August 12, 2007 Share Posted August 12, 2007 $39-40 at rock auto for my 01 outback...manufactured in Japan and in Everyway visually the same as the subaru one I pulled out..even down to the fine print on the new unit..works great Quote Link to comment Share on other sites More sharing options...
NoEyeSquareGuy Posted August 12, 2007 Share Posted August 12, 2007 Odd... I can't seem to find one on rockatuo's website that's even nearly that cheap. The cheapest they offer is an AIRTEX piece for $62 and change, for an '01 Legacy. As far as extensions to reach the bolt, I use a 12" extension on a 12mm(I think it's 12mm, anyway, might be 13mm) deep socket. With a standard socket, a 12" AND 3" extension seem to work well. Quote Link to comment Share on other sites More sharing options...
Petersubaru Posted August 13, 2007 Share Posted August 13, 2007 Odd... I can't seem to find one on rockatuo's website that's even nearly that cheap. The cheapest they offer is an AIRTEX piece for $62 and change, for an '01 Legacy. As far as extensions to reach the bolt, I use a 12" extension on a 12mm(I think it's 12mm, anyway, might be 13mm) deep socket. With a standard socket, a 12" AND 3" extension seem to work well. you are correct, it must be all sold out...the part # was the same as subarus...give rock auto a call and they may tell you when it may be re listed... Quote Link to comment Share on other sites More sharing options...
Rooster2 Posted August 13, 2007 Share Posted August 13, 2007 I just replaced the knock sensor on my 98 OBW with the 2.5 motor. It wasn't a bad job. As reported on previous posts, it is not a straight shot to get a socket on the head of the knock sensor. I used a 3/8 drive with an extension and socket on the end of the wobbler. I put some putty like caulk inside the socket, so the bolt head would stick inside the socket upon removal. Otherwise, it is difficult to retrieve the bolt in an area that your hand and fingers can't reach. Upon reinstall, I squished the bolt head inside the putty laced socket, and lowered the bolt into position, and tightened it up. I had a magnetic tip rod to retrieve the bolt should it have dropped out of the socket. This approach worked perfectly. Hope this tip helps you. Quote Link to comment Share on other sites More sharing options...
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