mtnpat Posted July 25, 2005 Share Posted July 25, 2005 I have an 05 2.5 litre normally aspirated Baja with 14k miles on it, and since about 10k miles, have noticed the motor knocking and pinging (pre-detonation?) when under load...it actually does it quite often. I run 87 octane unleaded, as stated in the owners manual. I have tried changing where I by my gas, but that has not helped. I have not yet tried running 89 octane. What octane gas does everyone else run? Anyone use combustion chamber cleaners / fuel additives to combat the knocking? Anyone ever heard of a knock sensor going bad (I think the 2.5 has one)? Thanks! Quote Link to comment Share on other sites More sharing options...
Olnick Posted July 25, 2005 Share Posted July 25, 2005 Are you getting a CEL? Have you checked for codes? Yes, a knock sensor can go bad--but remember it doesn't control or regulate knocking, it simply senses it and reports it to the ECU. Of course, if the KS is bad and doesn't report it the ECU won't know to correct. Hmmm! Hope someone with more knowledge than me will chime in. Good luck. Quote Link to comment Share on other sites More sharing options...
mtnpat Posted July 25, 2005 Author Share Posted July 25, 2005 Don't know what a CEL is, and I haven't had it to the dealer to check for codes. On a Chevy, some magic happens to retard the timing with the knock sensor senses the detonation, does a Subaru do the same thing? Quote Link to comment Share on other sites More sharing options...
felipe01forester Posted July 25, 2005 Share Posted July 25, 2005 "CEL" stands for "Check Engine Light." It's a little amber light in the dash that says, "Check Engine." Whenever a sensor reports a fault to the ECU (Electronic Control Unit, the car's on-board computer), the Check Engine Light turns on. If the Check Engine Light is on, take it to the dealer and ask them to run a diagnostic on the on-board computer to retrieve the fault code. If it is knocking and pinging, try upgrading the gas. If you're using 87, go with 89. If you're using 89, go with the high-grade stuff. It may hit you in the wallet, but at least your car will run smoothly. Quote Link to comment Share on other sites More sharing options...
mtnpat Posted July 25, 2005 Author Share Posted July 25, 2005 "CEL" stands for "Check Engine Light." Duh, silly me. No CELs. Still might take it to the dealer to have it checked out. So what octane is everyone else running, and do you experienced any knocking? thanks again Quote Link to comment Share on other sites More sharing options...
felipe01forester Posted July 25, 2005 Share Posted July 25, 2005 I run regular 87 octane in my Forester, and I haven't experienced any problems. I've also tried gas from different places (Shell, Chevron, RaceTrac, 7-Eleven) and haven't noticed a difference. Quote Link to comment Share on other sites More sharing options...
Lesbaru Posted July 30, 2005 Share Posted July 30, 2005 My 05 Impreza is picky about octane. (or else I just buy cheap gas... well, might be me) Anyway, it shakes at idle and knocks like it's gonna stall if I use 87. My 96 Legacy did the same thing (think it might be where I buy my gas) so I switched right away when the Impreza started hiccupping. I always use 89 or 92 now and have no problem. Quote Link to comment Share on other sites More sharing options...
zooma37 Posted July 30, 2005 Share Posted July 30, 2005 I own a 03' Forester and experienced the same issue. I have never owned a Subaru before and I wasn't sure what to think, but after reading suggestions from other owners in this forum, I switched to Shell 87. I've run Chevron and Mobil 87 and encountered lower gas mileage and knocking, which stopped when I switched to Shell. It seems that while Subaru tells owners regular is fine, the forester is very picky about which 87 brand. I'd run Chevron/Mobil 89 or Shell 87 and see what happens. I have seen better gas mileage and performance with Shell 87. Hope this info helps and good luck. Quote Link to comment Share on other sites More sharing options...
brus brother Posted July 30, 2005 Share Posted July 30, 2005 05 naturally aspirated Outback runs fine on 87 (various brands) but I am still struggling with a 00 Legacy GT that pings (since new) at various degrees more at 87 and less with less at the 93 octane level.(Yikes on the price). Knock sensor changed, computer "flashed", timing checked (one gear off at cam), Sea Foam upper engine cleaned, new plugs, cleaned throttle body. I'm now searching the possibility of demonic possession. Quote Link to comment Share on other sites More sharing options...
subie94 Posted July 31, 2005 Share Posted July 31, 2005 i use 87 in my 94 legacy,she's starting to knock an ping.seeing the price of gas these days.would using octane booster work the same,say like if i keep useing 87 and at fill-up i through in a bottle. maybe paying the extra 10 cents or so a gallon at the pump would be easier then doing that extra step of putting in a bottle of booster. Quote Link to comment Share on other sites More sharing options...
brus brother Posted July 31, 2005 Share Posted July 31, 2005 On a 94 you would expect enough carbon buildup to cause preignition or pinging so try a can or two of SeaFoam poured in the gas tank, sucked into a vacuum line and sprayed into the throttle body. New plugs might make a difference too BUT on a 05??? I'd deal with the dealership right now and get a record of everything. i use 87 in my 94 legacy,she's starting to knock an ping.seeing the price of gas these days.would using octane booster work the same,say like if i keep useing 87 and at fill-up i through in a bottle. maybe paying the extra 10 cents or so a gallon at the pump would be easier then doing that extra step of putting in a bottle of booster. Quote Link to comment Share on other sites More sharing options...
subie94 Posted July 31, 2005 Share Posted July 31, 2005 On a 94 you would expect enough carbon buildup to cause preignition or pinging so try a can or two of SeaFoam poured in the gas tank, sucked into a vacuum line and sprayed into the throttle body. New plugs might make a difference too . thanks for the suggestions :cool: i'll give it a try.gonna have to pick up acouple cans.1 for the oil an one for the fuel. or should i divide a can between the two. Quote Link to comment Share on other sites More sharing options...
subie94 Posted August 1, 2005 Share Posted August 1, 2005 thanks for the suggestions :cool: i'll give it a try.gonna have to pick up acouple cans.1 for the oil an one for the fuel. or should i divide a can between the two. bump.... Quote Link to comment Share on other sites More sharing options...
brus brother Posted August 2, 2005 Share Posted August 2, 2005 http://www.ultimatesubaru.org/forum/showthread.php?t=23344&highlight=seafoam here's the link bump.... Quote Link to comment Share on other sites More sharing options...
subie94 Posted August 6, 2005 Share Posted August 6, 2005 thanks Quote Link to comment Share on other sites More sharing options...
unverviking Posted August 6, 2005 Share Posted August 6, 2005 My 01 OBW pings like crazy as well. I only use 87, which ever brand is the cheapest at the time. I added a bottle of Castle Fireball, like always, Fireball stopped it. But next tank it was doing the same pinging... When the 01 was new we started using 89 in it, big mistake, spoiled it... Quote Link to comment Share on other sites More sharing options...
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