NEED HELP IGNITION PING

[03LegacyWgn]

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

[chuckthefuk]

EJ25 N/A in North America are tuned for 87 octane. Running a higher octane wont solve your problem, its just a band-aid..

Just my 2 cents.

P.S. $1.109 :-D and dropping!

[03LegacyWgn]

yea i know what its tuned for and im not doing a "band aid" im doing the process of elimination to see what is the possible cause, and up here its still 125+ fpr regular

thanks for your imput.
much appreciated.

[decke48]

my guess is the plugs might have a sharp spot on them causing predetonation. i would replace them with the lazer platnuim or double platnuim NGK

[warrior]

I would stick to copper plugs as copper is a better conductor of electricity and will give you a much better spark. The downfall to copper is longevity and that's where plugs like Iridium or "Quadruple" platinum (whatever gimmick they use now a days to sell to the masses) excel.

Where a-boot (hehe) are you in Ontario? I'm in Mississauga and wouldn't mind helping you out.

[Reason]

Where a-boot (hehe) are you in Ontario?

All I can think of is Terrence and Philip :lol:

Did you try replacing the coil pack?

[Huffer]

Is it entirely possible that you are using a bad tank of gas?

Are you feeling the engine knocking under load or something?

It could well be fuel related or even a sensor giving out.
Given that it started happening under light throttle, then redline, and now under most driving conditions I'm thinking it has to be a bad component that you either recently installed or it's bad fuel.

[03LegacyWgn]

Ive religiously used Shell fuel since ive started driving and the only time i don't is if im on a road trip and i need gas and a shell isn't around.

In in Thunder Bay wich is a far treck for some help but thanks anyways lol

Im not pulling any CEL's and i havent replaced any components other than my bolt on mods

[03LegacyWgn]

Im thinking knock sensor from what the tech told me at the stealership i work at so im going to test that and post results here for you guys.

[03LegacyWgn]

Well its been a while, made some headway tho, as you know the 00-04 models came from the factory with the piston slap in #3. The knock sensors used on our cars are a mass type that picks up all noise, therefor i (and other experienced auto techs) have come to the conclusion that the knock sensor is picking up the piston slap and adjusting the timing on me while driving in turn give me a ping.

So we tested our theory by unplugging the knock sensor to keep the ignition timing at a static timing, performance improved and no ping that was detectable to our ears, one issue tho, CEL came on cause the ECU was not receiving a reference voltage from the knock sensor. So one tech had mentioned he had this problem with his 2 wire GM sensor so he put in a 1ohm resistor in the circuit to turn off the CEL, one problem tho, our cars use a one wire sensor.

So we did some more figuring and decided to try and put a 1ohm resistor in series with the knock sensor to "dumb" down the reference voltage to the ECU, in turn tricking the ECU to think that it is receiving a "normal" signal from the knock sensor.

Road tested, performance was up and no noticeable ping at any throttle angle.

please post your comments and questions regarding our remedy

[ouch1011]

My concern with that would be that if the engine does ping, the PCM will never know and won't be able to correct. That can result in severe engine damage if the detonation is bad enough.

[03LegacyWgn]

it should still pick up the ignition ping if and when it were to happen, its simply limiting the operating parameters of the knock sensor to not pick up the louder noise of the piston slap.

I see what your saying and i will test voltages at the appropriate pin outs for the ECU and try smaller resistors and note any if at all changes i encounter, im sure if the ECU had any issues with what was going on it would let me know.

thanks for your comment, it puts another look onto the issue.