Low mileage 7 year N52B30 pinking - any solutions?!

Have had this car for a little over two years now and it has always had a slight rattle as you accelerate, mostly very hard to notice, but if you know about it you can hear it immediately. At first I thought it might be the exhaust flap, and then later on I thought it might be dual mass flywheel chatter. The car's mileage is currently 65k km, so quite low mileage for the age of the car - have done approximately 20k km in the time that I've had the car, combination of open road and town driving. Now being just over 7 years old mean that it is out of motorplan, so DIY and out of my own pocket from now onwards.

Anyway, the car was last serviced at the beginning of the year and I then took it in about a month or so before the motorplan ran out to diagnose and sort out this noise, which at the time I was still firmly believing to be chatter from the DMF - the technician immediately told me that what he was hearing was the engine pinking due to me being too low in the revs! Which to me does not make sense, 1800 - 2500 rpm with moderate throttle and an almost level service does not seem like too low revs. Any case, so they had the car for a few days to see what they could find - claimed to have tightened a loose exhaust bracket and then updated the car's software as well as resetting the adaptations.

For a few days it did seem better but came back - not convinced I went to another dealer for another opinion and was also told that the engine is pinking and it is "normal" with our fuel which is 95 octane unleaded. Have been trying to ignore it but it just bothers me too much for a car of this calibre!

Decided to replace the spark plugs since they were still the original ones that the car has always had and fitted them last night. Opted for the Bosch spark plugs based on RealOEM and left them with the preset 1 mm gaps. Old plugs didn't look too bad and OBC showed that they still have 35k km to go.

Car does not feel or sound any different, and while less, the engine is still pinking, so pretty disappointed and frustrated! What else can I have a look at or have checked?

Run a couple tanks of 98 through it; if it doesn't ping with that then I'd worry about it some more.

One of the adaptations is spark advance. That depends almost entirely upon the fuel octane: the engine advances the spark timing until it pings, then backs off. Some pinging is normal, especially at lower rpm - I'd say from idle until 2000 or more. There's a reason that people say don't shift until 3000 - it keeps the revs in the new gear at 2000 or more.

You might have the knock sensors tested (or replaced if you want to shotgun fixes.)

Originally Posted by floydarogers

Run a couple tanks of 98 through it; if it doesn't ping with that then I'd worry about it some more.

One of the adaptations is spark advance. That depends almost entirely upon the fuel octane: the engine advances the spark timing until it pings, then backs off. Some pinging is normal, especially at lower rpm - I'd say from idle until 2000 or more. There's a reason that people say don't shift until 3000 - it keeps the revs in the new gear at 2000 or more.

You might have the knock sensors tested (or replaced if you want to shotgun fixes.)

Thanks! Didn't mention knock sensors to see if it mentioned without me saying anything about it. Was wondering if it could be that. Unfortunately the highest octane that we have here is 95 octane, other option is to try a quality octane booster which I am not too keen on doing.

It is definitely a timing issue and something I did not mention is that I have been trying out the BMW Powerbox for the last month or so, and it does seem to aggravate the pinking - works by altering the timing and fuel/air mixture. Put it back to map 0 where it is disabled and the pinking is still there as before, but less.

Interesting I do find that changing at slightly higher than 3000 rpm the engine is generally happier, but most of the time you simply cannot avoid running the engine at these lower revs and of course my ears are trained to hear the pinking which of course then bugs me! LOL

The other annoying thing (not sure if this is related) that this engine does is suffer from is the midrange performance drop, around 4000 rpm, then above this goes like hell again! Strange...

I suspect low octane fuel is your problem. I've just been on a 3,000 mile round trip to Italy and due to force of circumstances filled up with their basic fuel (95 as I recall) and the car pinked badly. A couple of tankfuls of Shell V-Power (100 octane in Italy) and peace was restored.

Originally Posted by Phil325i

I suspect low octane fuel is your problem. I've just been on a 3,000 mile round trip to Italy and due to force of circumstances filled up with their basic fuel (95 as I recall) and the car pinked badly. A couple of tankfuls of Shell V-Power (100 octane in Italy) and peace was restored.

Hmm, yep watered down fuel FTL...

Maybe should give an octane booster a go and see if that at least stops the pinking - if it's the fuel then there's not much that I can do about it, but if not and still does this with a higher octane then need to find the cause.

This was last night just after replacing the spark plugs...



Six rather innocent looking coil packs, also took note of part numbers etc to cross reference with RealOEM.




Old plugs out - from left to right is front to rear of the engine, and then compared to one of the new Bosch plugs. Old BMW branded plugs were NGK of course.

them are not bad plugs I am not sure I would replace them. Especially with your current issue. New plugs wont fix it.

Originally Posted by Leekay07

them are not bad plugs I am not sure I would replace them. Especially with your current issue. New plugs wont fix it.

Well, was a long shot and can't hurt to have fresh plugs, so not regretting it. But was hoping it would cure this - process of elimination.

Did you ever get that engine "pinking" sorted out?. I am currently suffering the same issue and it bugs the hell out of me. Any advice welcome.

Originally Posted by S900ADY

Did you ever get that engine "pinking" sorted out?. I am currently suffering the same issue and it bugs the hell out of me. Any advice welcome.

Nope, not yet at least. I am going to have diagnostocs run to see what comes up - hoping to find an error code so that at least I can isolate the problem. I have read of various potential causes - three stage intake could even cause this, Vanos or Valvetronic maybe, then knock sensors. Really have no idea what else it could be. What frustrates me is that this is not an unheard of problem, yet I simply have not found any solutions on the many threads that I have read. So either this is not able to be sorted out, or nobody has bothered to post their solution for this...

I will however update this if and once I manage to get this sorted out - otherwise I doubt that I will keep this car for too much longer, this is too annoying for me!

I can only echo your words. Only had my 325i for three weeks. Purchased from a BMW dealer with a years BMW warranty, so i am going to push this engine "pinking" with them as hard as i possibly can. The car goes in on Weds to BMW for a full diagnostics, but told them that this may not find the fault code going on threads from other websites. They need to drive it with windows down to hear how bad it sounds under light load. It must be the knock sensor and not fuel?. I will keep you posted with the outcome from BMW after Wednesday.

I am not letting this one go!!

Originally Posted by S900ADY

I can only echo your words. Only had my 325i for three weeks. Purchased from a BMW dealer with a years BMW warranty, so i am going to push this engine "pinking" with them as hard as i possibly can. The car goes in on Weds to BMW for a full diagnostics, but told them that this may not find the fault code going on threads from other websites. They need to drive it with windows down to hear how bad it sounds under light load. It must be the knock sensor and not fuel?. I will keep you posted with the outcome from BMW after Wednesday.

I am not letting this one go!!

Yep, I left it a bit too late for BMW to sort this out - they had the car for a few days and simply updated software, and then wanted to spin the whole, "this is normal" nonsense. I test drove a few similar cars to mine with higher mileage in some cases and they did not suffer from this - and running on the same grade of fuel (we only have 95 unleaded) over here, so not a case of too low octane fuel. And also running Liqui Moly Injector Cleaner and no difference either, at least not so far. I reckon it is a sensor issue or something with the engine itself that is wrong - I don't buy this whole carbon build up story, simple reason that even if you take the car for a long spirited drive it is still pinking afterwards, surely any carbon build up would have cleared by then. So it must be something else, and if the knock sensors were doing their job then the timing should be quickly adjusted to prevent this...

I will update as I progress with this, but please keep us updated what BMW is able to find, and yes, push them to solve this - these engines are suppose to be very advanced and capable of running without pinking as far as I am concerned, and hence their "sheer driving pleasure" nature!

Originally Posted by Three_thirty_I

What else can I have a look at or have checked?

What octane fuel do you use?

Running 95 octane from BP. BMW have told me that this fine and should cause no problems that would contribute towards engine pinking.

I am reluctant to believe this to be an octane problem unless it is common amongst various N52 engined cars running on the same fuel. I have taken a few similar cars to mine for test drives and none of them have shown signs of pinking, and we only have 95 octane fuel in Cape Town, further inland at high altitudes they have 93 and 95 octane. Not ruling out the octane issue altogether, just questioning why other similar cars are not affected compared to mine. It is frustrating me to the point that I am already looking at going over to the dark side (diesel) - this engine is great when it wants to be, but is letting me down and my overall impression of these engines, my Wife's E46 320i seems to be a nicer, albeit far less power, engine in general!

In my experience with 2 328 models I have never heard engine pinging and there have been times I've run 87 octane. I think 95 octane RON is equivalent to 91 in the US which should not be an issue with this car. If you are actually getting pinging that you can hear, this is a serious problem IMO. The engine has a sensor and when pinging is heard immediately reduces the timing to compensate. I have a hard time believing this is something you can actually hear before the sensor takes over unless the sensor is bad. But even with 95 RON, your engine should not knock unless the combustion chambers are caked with carbon which is doubtful.

Originally Posted by Michael Schott

In my experience with 2 328 models I have never heard engine pinging and there have been times I've run 87 octane. I think 95 octane RON is equivalent to 91 in the US which should not be an issue with this car. If you are actually getting pinging that you can hear, this is a serious problem IMO. The engine has a sensor and when pinging is heard immediately reduces the timing to compensate. I have a hard time believing this is something you can actually hear before the sensor takes over unless the sensor is bad. But even with 95 RON, your engine should not knock unless the combustion chambers are caked with carbon which is doubtful.

+1!

At least this is my feeling too! I will either get to the bottom of this or let the car go... But will update as I get along with this!

Originally Posted by Three_thirty_I

At least this is my feeling too! I will either get to the bottom of this or let the car go... But will update as I get along with this!

Have you read codes?

Originally Posted by CALWATERBOY

Have you read codes?

Not yet, going to have this done next week - holding thumbs that it reveals the problem!

I will also get to the bottom of this. Will post the outcome from BMW after Wednesday when mine goes in for it's diagnostics.

How do i get to these?. Is this a diagnostics device to obtain codes?.

Originally Posted by S900ADY

How do i get to these?. Is this a diagnostics device to obtain codes?.

You can get a cable and then download the software - use your notebook to read and clear codes etc. This is something I need to do in the long term, but for now I just need to have the codes read ASAP.

There is a knock sensor that should prevent pinging. Did it get disconnected? One cause of pinging is hot spots from carbon build up in the combustion chambers, a few high RPM runs can clean some of it out. Warm it up and run it up close to the red line a few times in the lower gears or a good run on the highway.
David

Originally Posted by David Williamso

There is a knock sensor that should prevent pinging. Did it get disconnected? One cause of pinging is hot spots from carbon build up in the combustion chambers, a few high RPM runs can clean some of it out. Warm it up and run it up close to the red line a few times in the lower gears or a good run on the highway.
David

Well, once I have the diagnostics checked hopefully there will be an error code that will reveal the problem - I doubt that it's the ping sensor unplugged for the simple reason that the car was in to the agents a while ago for this very problem while the car was still under motorplan. And if it is a carbon build up problem then it should have cleared a long time ago - have given it plenty of WOT to red line spurts, and have been running the car on Liqui Moly Injector Cleaner. I am hoping that it is a faulty knock sensor since this will be an easy and not too costly repair in retrospect!

Originally Posted by boczek

Did anyone heard that this engines have cylinder head problems!? Maybe you hearing ticking sound comming from valves. Me and my friend have same models of bmw and they sound like sem. Trucks.after they seat for few days is the worst.dealer clames that from2005 to2008 the cylinder heads were miled t ao low and there is no fix for it short of replacing updated head.I hope I'm wrong and is hard do say whitout actually hearing how your noise sounds like.good luck but we are looking to unload both of them.

Yep, know about the known ticking problem suffered by some cylinder heads - not the case in mine since it is only under load at certain revs and never heard while the engine is simply idling of revved. A friend of mine had a 325i with this dreaded ticking, very different issue. Mine luckily does not suffer from this problem, but the pinking!

Pinking Update - well BMW have acknowledged that this engine pinking is not right - at least that is something. The car is still with BMW to fix a fault that showed up on the diagnostics that could cause this. From my understanding this is something to do with the catalytic converter causing something to kick in prematurely, maybe linked to the knock sensor???. Not sure exactly what, but will know more tomorrow when they replace the part under warrantly. Glad i got this BMW from a main deaaler with full BMW warranty.

Will post further techincal details tomorrow. We will get to the bottom of this.

Only had the car for three weeks. First BMW i have ever had so sorry if i sound a little dum!! She is a 2008 E93 325i M Sport.