04 WRX pinging

ummmm.

More details please.

What model?

What size engine?

What country are you in?

"Mike M. Miskul> Hi,

I have an 04 STi that does not knock when started cold. It has only been down in the mid 40s here so far and I let it idle for 90 seconds before driving. It will knock a little if I accidentally shift from 2nd to 5th instead of 3rd.

Under no circumstances should it knock at idle. If it were mine, I would have it spend the night at a dealer immediately.

While pondering the Universe, snipped-for-privacy@angelfire.com (John Coyote) wrote :

This is in regards an 04 wrx wagon in the states.

And in retrospect, pinging might be the wrong word, it sounds more like valve tapping, and only does this as I said the first 10 minutes and is only really audible at idle and low speeds. I suppose I could start the car and idle it and time how long it takes to go away to be more exact.

But its most definitely not engine knock or run-on. I found one item on google that suggests checking the plugs are properly connected, but this is a 6 week old car.

It could just be the boxer engine rumble.

Is this your first flat engine car?

it's probably piston slap.

very common complaint re: the boxer engine.

ken

I'm not sure the tensioner OR the piston slap is as prevalent in the WRX as the 2.5l . I'd try to confrim that by searching/asking at

or usmb.net . Woldn't want to dismiss it if it's something that needs attention.(the slap probably not, the tensioner yes. The slap will usually decrease as engine approaches operating temp. some tensioners do , others are reported to be noisy all the time.)

Carl

1 Lucky Texan

Ken Gilbert wrote:

I have a 2003 Outback 4 cyl with 10000 miles and also hear a pinging type noise from the motor between 20 and 30 miles when you start up, Have tried hi grade gas and did not see a difference, I am planing on changing to Bosh Plugs, maybe this will resolve the issue.

I'm just wondering if its just the way these engines are.. yours is like mine in that its fine after a short while, just a bit disconcerting as I've never had a car do this before. Then again, I've only driven v-8s.

Could be piston slap - well known but this is about the newest engine I've heard of this occuring in. Good news is it won't affect the lifespan of the motor. On the forums at

there are folks with over 250K that had it the whole time.

However, I'd be concerned you have a bad knock sensor. It tells the engine how far to move the timing before detonation is detected. Try to buy gas at the same location every time you fill up and disconnect the negative terminal of the battery, wait 15 minutes, hit the brake pedal a couple of times(or wait for an hour) to clear the ECU. Then it should learn the same octane gas and maybe not be confused.

Carl

1 Lucky Texan

Mike M. Miskul> While pondering the Universe, snipped-for-privacy@adelphia.net (Melvin) wrote > :

PISTION SLAP... if it is not noisy... Normal engine "slap" If under warranty have dealer check it for free. Could be timing chain tensioner (replaced free under power train warranty) Want to head mine..

look for subaru piston slap. Save file to HD then run the file.

It won't help. Actually I had 4 new pistons to get rid of the "slap" and they changed to "stardard" plugs after replacing pistions via SOA requirements. I was charged $30 labor in install spark plugs when the engine was already disassembled ? ? ? They also changed the timing belt tensioner first to remove the start-up noise (mine was bad). Got them to replace the three belts (timing and 2 drive belts) for just the $86.

Piston slap is a big problem in the auto industry. Check out "piston slap" and you'll find GM has a big problem and the customers are really upset.

Never thought of the "piston slap" affecting the "knock sensor"... humm that could affect the sensor and retard your spark. Worse gas mileage. Pulling the fuse would be better than the battery. All your radio stations would go too if you pull the battery.

With all the comments about piston slap, tensioners, knock sensors..

wouldn't these kind of problems be reflected all the time the car is running, not just going from cold to warm?

mike

Mild valve tap while cold is common, if not universal in these boxer engines. As the engine warms up, the metal expands and tightens up clearances and the tap goes away.

I have no idea how the other problems would go away at temperature.

While pondering the Universe, snipped-for-privacy@jkmicro.com (Jim Stewart) wrote :

So it sounds like I really shouldn't be too concerned unless I start hearing it when the engine is warm too.

mike

I think that's safe to assume. Try using Mobil1 10w30 next oil change to minimize it.