03LegacyWgn Posted October 1, 2008 Share Posted October 1, 2008 Hi Guys and gals, im having a problem and i was hoping someone here could shed some light on it and point me in the right direction. I have an 03 legacy wagon L 4EAT with an N/A 2.5l and 86000km's on the clock and i am experiencing what i believe is ignition ping, i have recently changed the plugs from my NGK iridium plugs to the stock subaru NGK plugs and tripple checked the gap, it helped a little bit so i filled my tank with mid grade 89 octane gas and yet again still happens but not as much. My mods are a CAI, crank and alt pullys. Now as you know this motor has the distributor less ignition system so i cant adjust the ignition timing. Now i didnt notice this till id say 5000 km's after i installed the iridium plugs, it would mainly happen under light throttle off the light or at red line, and now does it under most types of engine load. If someone knows what is causeing it or what i can do to fix it that would be greatly appreciated, my next step is to go to 91 octane but im trying to hold off since gass is worth an arm and a leg in my neck of ontario. Thanks in advance and no responce is a stupid one all suggestions are welcome! Cheers Steve ::edit:: mods if this is in the wrong spot im sorry please place in appropriate spot. 03 BH Mods: Group A Alt & Crank Pullys and end links, CIA, JDM L7 Grille, JDM HID lights, JDM rear tails Stromung CBE, KYB GR2's W/ H&R springs. Link to comment Share on other sites More sharing options...
WhatV8 Posted October 2, 2008 Share Posted October 2, 2008 Steve, you may just have a buildup of carbon deposits in the combustion chamber. The carbon deposit heats up enough to cause pre-ignition ping, which is likely what you are hearing based on the conditions it started with. I would try running a couple of bottles of cleaner through your system to see if that helps before going the professional cleaning route. I have had good success with the Chevron Techron & Pro-Gard products. They used to sell an intake valve/combustion chamber cleaner that worked wonders on a former vehicle that I owned. That former car had leaking valve stem seals that would allow crud to build up on the top side of the valves and sap my gas mileage down. On a particular road trip I ran (3) bottles of the iv/cc cleaner through my tank and bumped my mileage up from 22 to 27mpg, not bad for a $15 investment at the time. I still run a bottle of Techron through both my wife's and my own Subie's tanks every oil change to prevent any issues. Another self-cleaning option is SeaFoam motor treatment. I haven't used it personally, but I have friends that swear by it and have seen some good results using it. You other options are to have your engine professionally 'flushed'. This isn't a cheap option, but saves the cost of performing any kind of a teardown. Good luck. Link to comment Share on other sites More sharing options...
03LegacyWgn Posted October 3, 2008 Author Share Posted October 3, 2008 its not nearly as bad as it was b4 so its somewhat better, but it still happens so that leads me to believe that its the knock sensor. 03 BH Mods: Group A Alt & Crank Pullys and end links, CIA, JDM L7 Grille, JDM HID lights, JDM rear tails Stromung CBE, KYB GR2's W/ H&R springs. Link to comment Share on other sites More sharing options...
03LegacyWgn Posted October 3, 2008 Author Share Posted October 3, 2008 and i cant believe that the whole write up i did on the knock sensor didn't post.... 03 BH Mods: Group A Alt & Crank Pullys and end links, CIA, JDM L7 Grille, JDM HID lights, JDM rear tails Stromung CBE, KYB GR2's W/ H&R springs. Link to comment Share on other sites More sharing options...
porcupine73 Posted October 14, 2008 Share Posted October 14, 2008 Yah maybe run some seafoam or similar through the intake. Many people report good results with this. Usually do it engine warm, then let it drink in like 6 oz through a vacuum line atop the intake manifold, shut down for say 10 minutes to let it work, then fire 'er up and let it drink in somemore. This should do a world of good in getting carbon and junk out of the intake and off the valves and such. the 'carbon cauliflower' can really cause performance issues and ping. Link to comment Share on other sites More sharing options...
03LegacyWgn Posted October 16, 2008 Author Share Posted October 16, 2008 been done already, thanks tho. 03 BH Mods: Group A Alt & Crank Pullys and end links, CIA, JDM L7 Grille, JDM HID lights, JDM rear tails Stromung CBE, KYB GR2's W/ H&R springs. Link to comment Share on other sites More sharing options...
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