brus brother Posted May 14, 2005 Share Posted May 14, 2005 OK to recap, 2000 Legacy GT from day one pings with recommended 87 octane. I had been using 89 or 91 octane until the price of gas equalled my mortgage and then got serious about figuring it out. I'm just barely under an extended warranty and want to get this settled. The car still pings under LIGHT load using 89 octane (seems like if I floor the pedal for hard acceleration it's OK). The following has already been addressed. New plugs Upper engine and fuel injectors cleaned New knock sensor New rear O2 sensor Timing belt changed at 70K while determining that the timing was off one tooth (apparently misset at factory but the computer never threw a code??) The computer was flashed to the latest parameters Is it possible that the computer is faulty? Any other suggestions appreciated. Quote Link to comment Share on other sites More sharing options...
99obw Posted May 14, 2005 Share Posted May 14, 2005 What kind of upper engine cleaning did you do? It might be worth it to you to do something aggressive like a soak with LC20 . This stuff is amazing, it will dissolve all carbon in the CC and on the piston. I use it for that purpose in engines small and not-so-small. It's basically a solvent/oil type substance. Looks like light-colored engine oil, but the smell will knock you on your butt. This company also sells a product called FP60. Fuel Power is the only product I have found that eliminates the cold start rough idle in my Jeep. Very good products. Can you rent or borrow a borescope? It might be helpful to eliminate carbon deposits as the cause by actually looking in the cylinder. The only other suggestions I have are unlikely, but you have tried most of the normal stuff. Does it have EGR? Malfunctioning EGR can cause pinging due to increased combustion temps. Unlikely that you would have EGR troubles without a MIL. An IAT sensor that's out of spec can cause pinging due to incorrect mixture and timing. A malfunctioning MAP or MAF could cause mixture problems that might cause pinging. A manufacturing defect in one of the combustion chambers that causes a high spot or increased compression could cause pinging. Quote Link to comment Share on other sites More sharing options...
brus brother Posted May 14, 2005 Author Share Posted May 14, 2005 I used Seafoam sucked through the vacuum port on the throttle body, let it sit 5 minutes then started it up and created the infamous smoke screen. Anyway, the issue was present since the first tank of gas, probably eliminating carbon buildup from the differential diagnosis. I will pass your suggestions to the tech next week and post back. What kind of upper engine cleaning did you do? It might be worth it to you to do something aggressive like a soak with LC20 . This stuff is amazing, it will dissolve all carbon in the CC and on the piston. I use it for that purpose in engines small and not-so-small. It's basically a solvent/oil type substance. Looks like light-colored engine oil, but the smell will knock you on your butt. This company also sells a product called FP60. Fuel Power is the only product I have found that eliminates the cold start rough idle in my Jeep. Very good products. Can you rent or borrow a borescope? It might be helpful to eliminate carbon deposits as the cause by actually looking in the cylinder. The only other suggestions I have are unlikely, but you have tried most of the normal stuff. Does it have EGR? Malfunctioning EGR can cause pinging due to increased combustion temps. Unlikely that you would have EGR troubles without a MIL. An IAT sensor that's out of spec can cause pinging due to incorrect mixture and timing. A malfunctioning MAP or MAF could cause mixture problems that might cause pinging. A manufacturing defect in one of the combustion chambers that causes a high spot or increased compression could cause pinging. Quote Link to comment Share on other sites More sharing options...
Noel Posted May 18, 2005 Share Posted May 18, 2005 I'm having the same problem with pinging with my wife's 01 Outback 2.5L. It has gotten worse since the weather is above 70degrees. I just dumped a bottle of Techron into the tank. We will see if that helps. I imagine it is due to carbon buildup (Effectively increasing the compression ratio of the engine) since she does only stop and go driving in city traffic with lots of idling. Noel Quote Link to comment Share on other sites More sharing options...
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