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Discussion Starter · #1 ·
How does the 2.5NA determine ignition timing ?

In other words is there a sensor on the flywheel or somewhere on the crankshaft ?

This may be a little far out there, but here is why I'm asking.

Ever since I bought my 2009 Forester it has pinged. I wrote SOA shortly after I bought it and they instructed to take it to my dealer. The dealer was not interested at all and said they couldn't hear any pinging.

Recently I decided to try another dealer. This dealer took a ride with me and immediately acknowleged that the engine was pinging and didn't like the sound of it at all. He did a cursory check of ECU readings and couldn't find anything obvious so he asked me to make an appointment to leave it for a day (next week).

At one point he said that it really sounded like the timing was advanced too far, but then added that the timing was controlled by the ECU and wasn't adjustable.

That got me to thinking. Is it possible that when the engine was assembled that the crank was rotated a tooth or 2 advanced which now tricks the ECU into advancing the timing too far ??

I know that sounds far out, but I thought I would ask.

Thanks !!
 

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1998 Forester
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There are at least two sensors that impact the timing. For instance, there is a crankshaft position sensor and a camshaft position sensor. There is also a knock sensor that should retard timing when your engine pings.

What octane rating of gas are you using? Have you tried a higher grade? What is your altitude? Is your CEL on?

If you can do an ECU scan you could log the engine at idle and at higher revs to see what is happening as well.

There are many diagnostic things to be done before dis-assembling the engine to get at the timing belt.
 

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Discussion Starter · #4 ·
There are at least two sensors that impact the timing. For instance, there is a crankshaft position sensor and a camshaft position sensor. There is also a knock sensor that should retard timing when your engine pings.

What octane rating of gas are you using? Have you tried a higher grade? What is your altitude? Is your CEL on?

If you can do an ECU scan you could log the engine at idle and at higher revs to see what is happening as well.

There are many diagnostic things to be done before dis-assembling the engine to get at the timing belt.

Thanks for the info. To answer some of your questions, I'm using 87 octane (what Subaru says the car requires); I've tried a higher grade and it helped, but did not completely eliminate the ping; I live in Cincinnati Ohio, don't know the altitude, but not extremely high; No CEL

I agree about the diagnostics, and at this point I'll leave it to the dealership, since I've found one that will try and help.
 

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Discussion Starter · #6 ·
Manual, auto ?

Driving style?
Auto

Driving style = Grandma :icon_wink:

Pinging is most noticeable when starting from a stop. Give it a little gas and it will ping until about 2K rpms. Interestingly jack rabbit start will not ping, and any situation with hard throttle doesn't ping. Only light throttle. Which makes me feel like the ECU is in control.

Sometimes I can hear very slight pinging while I'm cruising along the highway with little load on the engine.
 

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2014 Impreza Ltd CVT
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If you have a lot of miles, it could be carbon buildup on the pistons. Very Common. Try an internal engine cleaner like SeaFoam. Some here love it, others hate it. I have had very good results from it every time I use it.

Or you could try another brand of internal engine cleaner.
 

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Discussion Starter · #8 ·
If you have a lot of miles, it could be carbon buildup on the pistons. Very Common. Try an internal engine cleaner like SeaFoam. Some here love it, others hate it. I have had very good results from it every time I use it.

Or you could try another brand of internal engine cleaner.
Fair enough, but note in my original Post that the car pinged from the very beginning and I both wrote SOA and took it back to the dealer I bought it from. I doubt carbon could have built up that fast.

If the current dealer has no success I'll try some seafoam.

Thanks.
 

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2010 Forester 2.5 MT
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Auto

Driving style = Grandma

Pinging is most noticeable when starting from a stop. Give it a little gas and it will ping until about 2K rpms. Interestingly jack rabbit start will not ping, and any situation with hard throttle doesn't ping. Only light throttle.....
Ditto

Interesting that you get it in an AT vehicle. Mine is MT.

2010
BP 87 Octane consistently
650 to 900 above MSL

Tinking/pinging for a few revolutions in all four gears in town when accelerating when outside temps are above 80F and engine is good and warm. Primarily occurs when letting the clutch out. 15,000 miles at this point.
 

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Valve timing is set with the timing belt. Theres a crank position sensor in the center and a Cam position sensor on each head. Ignition timing is controlled by those sensors, the ecu map, and the knock sensor.

Are you on original spark plugs? You could potentially try a step colder spark plug if everything else checks out ok.
 

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2010 forester 2.5x prem.
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my 2010 n/a pings..

I just had the 15000 check up and mentioned to the dealer that i was getting a metallic rattle upon acceleration. Turns out it was pinging what you just described. Dealer told me to change brands of gas. Did that and no change. Tried mobil 89 for a tank and still pinged but not as much. Then put in mobil premium 93 for a tank and no ping! Have not taken it back to dealer yet. :huh:
 
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