Subaru pinging

[Brogy]

Hi, this is a question for my dad, his 2003 subaru outback, with about 25,000 miles, 4 cylinder auto trans, pings.

He changes the oil every 3000 or 3 months. The car has mostly short trips of less than a mile each way to work, but everyonce in a while he'll take a long trip and get it nice and warm.

It's been pinging for a good while now, not at idle, when under load. I understand this is a common problem, but he wants to know what the problem is. He changed the plugs (bosch), and it went away for a few days, but came back. The dealership also replaced the hydraulic lifters under warranty, but still pings.

any help or ideas are appreciated, thank you.

 

[Quest]

Get NGK iridium or platium plugs first and then go from there (or Denso)

Subies hate Bosch plugs, period.

 

[Gary Allan]

Is there some heat range problem with Bosch plugs (assuming that they're actually supposed to be in that engine and not a "one size fits many" +2+4 thing)

Otherwise, help me out on the pinging aspect here, Quest.

Brogy: Does this ping during his short commute? He may be up to op coolant temp for 1/2 of that drive unless it takes him a long time to do under a mile

 

[XPR]

Add a bottle of Amsoil PI fuel treatment to it. The pinging maybe caused by carbon build up.

 

[Brogy]

It only pings when up to temp, when its cold its quiet.

 

[TexasHonda]

There is a pre-ignition detector (knock detector) on the car which should retard the timing to prevent spark advance pre-ignition. However, if the knock detector is not working, it should set the Check Engine Light (CEL). If no CEL, there may be something else such as low EGR flow causing the pinging.

I had the knock detector fault code on my 99 Forester, but there never was any pinging.

good luck

 

[Eddie]

My 2000 Forester exhibited a slight pinging from day one until I sold it with 126,000 miles. The slight pinging demonstrated to me that the ignition was being advanced for maximize efficiency. The engine did this only under light acceleration and never did the hard metallic knocking. I suggest that you get a bottle of TECHRON FUEL SYSTEM CLEANER ( 20 gallon size). WalMarts for ~ $8.00 and follow directions.

 

[MrCritical]

Short trips. Low mileage. Sounds like carbon build up. Use the fuel cleaner recommended above and switch to Top Tier fuels (if you haven't already).

 

[ITSMR2U]

My '03 Forester pings while warm and going uphill. It is not a knock but is a light ping which is essentially harmless. Try some techron. Also, if it's a worry, going up one grade in gas octane will help

 

[mechtech2]

I'd run a tank of fuel with a good cleaner/decarbonizer in it.
Redline S1, Chevron Techron [strongest solution they have], and Gumout Regane are good and proven products.
Going up a grade in fuel, [like 89 from 87] may be a good solution. It should run better and regain some of the costs incurred by the higher octane.
You thermostat may be running too warm - too hot and you'll ping. Also, a coolant sensor may be faulty, causing the computer to think the engine is cooler than it really is. This would lead to over advanced ignition timing and pinging.

 

[artificialist]

My grandma's 1993 Buick Roadmaster had the knock sensor fail. It didn't cause a check engine light. Once I put a new sensor in, it shut up the knocking right then.

That in mind, engine self-diagnostics improved significantly between 1993 and 2002.

However, My mom had two cars that would always ping above 4000 RPM. A 1999 Honda CRV and a 2002 Toyota Solara. I'd occasionally run a can of decarbonizer in those engines, but the knocking never really ended.

 

[porcupine73]

What octane fuel is being run and what octane is recommended in the owners manual?

First suggestion would be a good injector cleaner, some amount added every time fuel is added (not just a big dump in every 3000 miles). I like redline SI-1 with Lucas UCL. I have tried the new amsoil product in my soobs and that works well too.

Carbon buildup is mentioned as a possible issue on endwrench.com, an official Subaru site. Going to higher octane fuel can be tried at least short term though it can take a few tankfuls to notice any difference.

Typically Subaru's do like NGK plugs and their own OEM spark plug wires, especially the pre-2000 model years. Some of it may have to do with its waste spark setup which esentially fires the opposing cylinders at the same time, though one is one the exhaust stroke.

 

[porcupine73]

A couple good soob specific boards if you're interested are www.ultimatesubaru.org and www.subaruoutback.org

 

[Titan]

Did they have hydraulic lifters in 2003? I thought they were solid?

My guess would be carbon build-up, as some others have mentioned. Or, what you are hearing isn't pinging, but, the typical noisey Subaru. I had a 2.5 Subaru that pinged only on light throttle...meant I was getting maxium fuel economy (it would get mid-upper 30's going low-mid 60 mph range, manual transmission), but, if I pushed it at all, the pinging stopped.

Current two Subaru's don't ping enough that I can hear it, they're automatics.

 

[Merkava_4]

Quote:

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Also, a coolant sensor may be faulty, causing the computer to think the engine is cooler than it really is. This would lead to over advanced ignition timing and pinging.

---

+1

 

[porcupine73]

Subaru stopped using hydraulic lash adjusters HLA's after 1996. After that they're solid, with either screw and nut adjustment which is easy to work with, or some weird bucket deal with shims.

Also Subaru's love to get rattly exhaust heat shields that can be mistaken for other sounds as well.

 

[mikeg5]

SEAFOAM.. 3 cans to 4 gallons of gas, run to empty, THEN take one can and suck in a 1\3 can at a time through the pcv valve. let it sit for hours then crank the car up and run it down the road till it quits smoking. then repeat until can is empty, best thing i have used yet. after all that, change the oil. i gained 3mpg and better idlingin my truck plus no pinging since i had done it back about 20k miles ago. it has 97k miles on it now

 

[Mudcat]

After doing a little googling, it appears that pinging Subarus are well documented. What I thought was unusual is that some of these owners reported problems with one year old cars.

Here's one thread where Subaru owners discussed the issue. One owner reported his issue was resolved when the dealer installed thicker head gaskets to lower the engine compression and decarboned the engine.

Anywho, it might be valuable to review Technical Service Bulletins (TSB) for the car.

 

[Mudcat]

After doing a little googling, it appears that pinging Subarus are well documented. What I thought was unusual is that some of these owners reported problems with one year old cars.

Here's one thread where Subaru owners discussed the issue. One owner reported his issue was resolved when the dealer installed thicker head gaskets to lower the engine compression and decarboned the engine.

Anywho, it might be valuable to review Technical Service Bulletins (TSB) for the car.

 

[mikeg5]

SEAFOAM