[kppanic]

https://www.youtube.com/watch?v=V_l22M9EfZ8&feature=youtube_gdata_player

15 sec in.

Another problem with the car!!!

There's a pinging noise coming out of the car while accelerating and decelerating, and now even when at idle.

And when I press the gas pedal the engine sounds like a friggin F-150 truck.
Not only at idle.

This is starting to piss me off.

and NO it's not the gas. I have not touched anything less than 91.

[rado]

Pinging on acceleration makes you think pre-ignition (or knock), but the fact that you hear it at idle and on deceleration indicates it must be something else. Obviously you should take it to the dealer, but have you tried listening with the hood open to try to locate the source? It's possible that it could be a valve-related failure, but it seems more likely that something external to the engine has come loose (exhaust heat shield, motor mount, ...), and the sound is a mechanical "rattle". Good luck with it, and let us know what the dealer finds.

[kppanic]

Originally Posted by rado

Pinging on acceleration makes you think pre-ignition (or knock), but the fact that you hear it at idle and on deceleration indicates it must be something else. Obviously you should take it to the dealer, but have you tried listening with the hood open to try to locate the source? It's possible that it could be a valve-related failure, but it seems more likely that something external to the engine has come loose (exhaust heat shield, motor mount, ...), and the sound is a mechanical "rattle". Good luck with it, and let us know what the dealer finds.

This happened 3 fill-ups ago and is getting worse.

I had gone and put Shell V-Power for 3 pervious tanks and yesterday I dropped by Costco for their wholesale premium, but no change in engine state.

When I listen to the engine with the hood open at idle, i hear the normal chunk-chunk-chunk-chunk but every once in a while (i.e. ~30 sec) I can hear chunk-chunk-chunk-CRINK (like a metal grinding against metal) and the engine shakes a bit and then goes back to chunk-chunk-chunk cycle.

I hope it's not a valve problem... I've only got ~4800kms on it. Calling the dealer today.

edit: called the dealer... they only have a loaner avail next Tuesday (25th) so i'll bring in the car then. Reported the following problems:
1. Pinging engine/rough engine;
2. Passenger restraint malfunction fault;
3. Off-steering (vehicle veers to the left slightly); and
4. General update to the vehicle software.

I'll see how this goes...

[Michael Schott]

Very doubtful it's preignition. Even if the sensor has failed under 93 octane this engine should not ping. Let us know what the dealer says.

[sparkyg]

I wasn't aware Costco sold Top Tier approved fuel.

[kppanic]

Originally Posted by Michael Schott

Very doubtful it's preignition. Even if the sensor has failed under 93 octane this engine should not ping. Let us know what the dealer says.

I am very curious as well. I will def update the thread once the dealer sees the car. The metallic shake and vibration at idle definitely worries me.

Originally Posted by sparkyg

I wasn't aware Costco sold Top Tier approved fuel.

They sell whatever they can get their hands on, so in Canada it's a variety of Esso, Petrocan, Shell, etc.

Gas consumption is increasing rapidly as well. Averaging per tank is (all in L/100km)

1. 10.4 - 22.6 mpg (dealer tank -- i think they gave me 95 but no matter)
2. 10.2 - 23.0 mpg (Petrocan 94)
3. 9.9 - 23.8 mpg (Costco prem 91)
4. 10.7 - 22.0 mpg (Shell V-Power 91)
5. 11.3 - 20.8 mpg (Shell V-Power 91)

[nbennettksu]

The majority of the time, pinging goes with fuel. I know in your first post you specifically say not to blame fuel. However, maybe you got bad gas and it hasnt completely cycled out.

[sparkyg]

There is a wide range of fuel quality in Canada. Not all of it is great for BMW turbo cars designed for very low or no ethanol fuel.

Maybe you got a nice big ol dose of high ethanol fuel and you lucked out and got water along with it. The water will sit in your fuel till its cleared.

Try a bottle of gas line anti freeze and see if that clears it.

Get some good fuel from a diff station than your normal locations too.

[NISFAN]

Originally Posted by Michael Schott

Very doubtful it's preignition. Even if the sensor has failed under 93 octane this engine should not ping. Let us know what the dealer says.

Pre-ignition is a very serious engine fault (ignition before the spark plug has even fired)....sure you don't mean detonation?

[rado]

Originally Posted by NISFAN

Pre-ignition is a very serious engine fault (ignition before the spark plug has even fired)....sure you don't mean detonation?

You're right, I made the mistake first and mentioned pre-ignition when I should have written detonation. FWIW people often mix these terms, but the fact is that what most folks would describe as "pinging" is detonation.

Regardless, based on the OP's description, I doubt the problem is either one (detonation or pre-ignition). You just don't get either during deceleration. On full lift deceleration, the ECU will do a fuel cut, so there can be no ignition of any kind, no matter how bad the gas.

[NISFAN]

Originally Posted by rado

You're right, I made the mistake first and mentioned pre-ignition when I should have written detonation. FWIW people often mix these terms, but the fact is that what most folks would describe as "pinging" is detonation.

Regardless, based on the OP's description, I doubt the problem is either one (detonation or pre-ignition). You just don't get either during deceleration. On full lift deceleration, the ECU will do a fuel cut, so there can be no ignition of any kind, no matter how bad the gas.

Agreed, another clue is that timing would have to be seriously out to pink at idle too.

Sounds like some mechanical fault....surprised BMW wouldn't want to listen to the car straight away before more damage is caused.

[MaestroAl]

It's either not suffering from knock or you've got a serious fault. There's no way the ECU would allow the amount of knocking you're describing. It would flood the cylinders, back off the throttle and halt the timing instantly any knock was detected. Seriously just ain't gonna happen on a modern car and certainly isn't going to be cause by "bad gas". No such thing. BMW is a global brand and their cars will work in deepest, darkest Africa, Columbia, Japan, Russia ... wherever you can get gas. The ECU compensates fro different octane levels and prevents knock.

Either you're describing something that isn't knock or your car is completely fux0red and it's about to explode

[mocohead]

It almost sounds to me like you are describing the AC compressor engaging.

[kppanic]

Ok so after work I drove around 50km to see what the heck is going on.

First of all, it's definitely pinging. It got louder and even my wife hears it now. It used to be "omg do u hear that?" and she would go "omg leave the car alone I don't hear anything." to "oh wow I hear it now too." Every time I press on the gas it pings at low to mid rpm.

Secondly, it pings at decel but not necessarily the whole time, it only pings when engine break occurs and between approx 1000 - 2000 rpm.

[Michael Schott]

Originally Posted by NISFAN

Pre-ignition is a very serious engine fault (ignition before the spark plug has even fired)....sure you don't mean detonation?

I'm sure detonation is the correct term and that's the context that I meant to express. Thanks for the correction.

[MaestroAl]

I concur. Detonation, knock, pre-ignition ... all the same thing - the fuel igniting on the compression stroke of the piston Good way to bend a rod, that

[NISFAN]

Nope Detonation and pre-ignition are NOT the same thing.

I don't mean to be pedantic.....I am an engineer

[MaestroAl]

Well technically pre-ignition is knock but knock is not necessarily pre-ignition

[Michael Schott]

Originally Posted by NISFAN

Nope Detonation and pre-ignition are NOT the same thing.

I don't mean to be pedantic.....I am an engineer

Thanks. I think what's important in this thread is that the chances the OP is truly suffering from detonation are slim to none. There are systems on the car to prevent this.

[NISFAN]

Originally Posted by Michael Schott

Thanks. I think what's important in this thread is that the chances the OP is truly suffering from detonation are slim to none. There are systems on the car to prevent this.

Correct, unless the knock sensor circuit failed and the ECU went for maximum advance due to no knock retardation. But again you wouldn't get ping on overrun, just under load.

Difficult to diagnose a sound without hearing it first hand, but description could be anything from loose ancillaries to a spun bearing. A video would be more informative

[ocso1606]

Gas grade?

[mocohead]

It is neither knock nor detonation if it is happening on deceleration.

OP please take your car to the dealer and let us know what they find. Diagnosing noises on the internet it almost impossible.

Can you post a video of the car making the noise?