BMW Z3 3.0 "pinking". I've tried the obvious cures....
Discussion
Hi,
I bought my 2002 BMW Z3 3.0 sport in October 2008 and, as always with my cars, I ALWAYS use Shell V-power petrol. The car has 58,000 miles and FBMW Service History. It was last serviced 1,000 miles ago and had new spark plugs fitted.
I've noticed a noise that I think could be "pinking".
It's most noticeable in 3rd and 4th gear at about 2,000-2,800 rpm, when I'm accelerating. If I snap onto the throttle, there's usually one metalic "clink" sound at the above engine speeds. If I'm accelerating gradually but quickly through the gears, I can hear half-a-dozen or so "clinks" at 2-3k rpm.
It only happens when the engine's up to normal temperature. The gauge sits bang in the middle. I recently changed to Tesco 99 fuel, but there's been no change. The car otherwise runs fine and pulls strongly.
Is it worth fitting a new knock sensor or coils or paying to have it diagnosed? As I say, I only think it might be pinking.
Advice, experience and suggestions would be appreciated.
Cheers, Neil
I bought my 2002 BMW Z3 3.0 sport in October 2008 and, as always with my cars, I ALWAYS use Shell V-power petrol. The car has 58,000 miles and FBMW Service History. It was last serviced 1,000 miles ago and had new spark plugs fitted.
I've noticed a noise that I think could be "pinking".
It's most noticeable in 3rd and 4th gear at about 2,000-2,800 rpm, when I'm accelerating. If I snap onto the throttle, there's usually one metalic "clink" sound at the above engine speeds. If I'm accelerating gradually but quickly through the gears, I can hear half-a-dozen or so "clinks" at 2-3k rpm.
It only happens when the engine's up to normal temperature. The gauge sits bang in the middle. I recently changed to Tesco 99 fuel, but there's been no change. The car otherwise runs fine and pulls strongly.
Is it worth fitting a new knock sensor or coils or paying to have it diagnosed? As I say, I only think it might be pinking.
Advice, experience and suggestions would be appreciated.
Cheers, Neil
Edited by superbracey on Thursday 4th June 21:53
One option to try for free is to disconnect the battery for a short while, letting the ECU reset itself, and relearn the AFR (air/fuel ratio) again.
If still doing it, then a sensor(s) may be the cause, but an OBDII read should show up any fault codes relating to sensors, which if it is clean/other codes, then the fault lies elsewhere.
Make sure the air filter is clean - remove any debris in the airbox.
And lastly, one other element might be the throttle body butterfly sticking - there's a few cleaners you can spray in whilst running the engine to clean it and the sensor contained therein.
If still doing it, then a sensor(s) may be the cause, but an OBDII read should show up any fault codes relating to sensors, which if it is clean/other codes, then the fault lies elsewhere.
Make sure the air filter is clean - remove any debris in the airbox.
And lastly, one other element might be the throttle body butterfly sticking - there's a few cleaners you can spray in whilst running the engine to clean it and the sensor contained therein.
Check your spark plugs, you could run one range colder if they look too hot. It will help you see if its getting a little hot in there anyway.
As you mention snapping the throttle open then you will be in power enrichment mode so any issues are not likely with the o2 sensors though some vehicles use them to build a table of correction values which are also used at WOT.
It would be good to scan for any historical or current codes before you reset the PCM.
How is engine temp looking? Maybe check the coolant and make sure you have the right mix of stuff and not just water which can cavitate, you could also run water wetter or equiv to keep the heads cooled as best as possible.
It will either be too much spark advance, running too lean, or running too hot IMO
Maybe your knock sensors have gone a bit AWOL Im not sure how they work in the BMW
As you mention snapping the throttle open then you will be in power enrichment mode so any issues are not likely with the o2 sensors though some vehicles use them to build a table of correction values which are also used at WOT.
It would be good to scan for any historical or current codes before you reset the PCM.
How is engine temp looking? Maybe check the coolant and make sure you have the right mix of stuff and not just water which can cavitate, you could also run water wetter or equiv to keep the heads cooled as best as possible.
It will either be too much spark advance, running too lean, or running too hot IMO
Maybe your knock sensors have gone a bit AWOL Im not sure how they work in the BMWI suggest you take it to the people who serviced it and let them listen to the noise. It could be something completely different. If it's pinking it's most likely to be cause by a lean mixture, too much ignition advance, fuel octane too low, too much compression or hotspots in the chamber. Hotspots could be caused for example by the plugs getting too hot; perhaps they fitted the wrong grade of plug (or perhaps they fitted the standard grade and you were previously using a colder grade).
Assuming the car appears to be normal.
Buy some octane booster and throw it in, and see if it makes any change. If not, its unlikely its pinking. Failing that, you'd be better taking it to a "tuner" for wont of a better description. As they would be in a better position to tell if it is pinking, and diagnose it, as opposed to a normal mechanic.
Buy some octane booster and throw it in, and see if it makes any change. If not, its unlikely its pinking. Failing that, you'd be better taking it to a "tuner" for wont of a better description. As they would be in a better position to tell if it is pinking, and diagnose it, as opposed to a normal mechanic.
I presume this engine has knock sensors? If so try disconnecting them from the loom (ie. no electrical connection, don't just take them off the block), the ECU will see there not working and run in a limp home mode, this will stop it running active spark control and run off a much retarded speed/load spark advance map*. If this stops this noise its safe to assume the engines pinking as opposed to timing chain rattle etc, then you can take it from there.
- assuming it runs a similar strategy to the Ford/Visteon PCMs with active spark control
My thing is Saab Turbos, your setup may well be different. Saab use the spark plugs to monitor knock.
What plugs are you using, there is a well supported theory in the Saab world that platinum tipped plugs certainly add to plug longevity, however the platinum actually interferes with the ionisation process, giving a spurious knock count.
If your BMW has a separate knock sensor and doesnt use the spark plugs then please ignore what I have written.
I am currently seeing knock on cylinder 1 of my Saab, The DI cassettes are notorious for failing if using anything other than NGK R plugs. So my next plan is to swap cassettes to see if that help things out, it has four individual coils maybe similar to yours.
Just a point I have never heard my Saab knocking, are you sure its that ?
Good luck
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