BMW 320D pinking?????

AnastieByte · 15 Jan 2007 at 20:24

I posted this on BMWLAND but also wanted any opinions in here. I know diesels cannot suffer pinking as petrol cars. But I got my 2003 320D SE with only 33000m last week from a main dealer with full approved warranty and service and maintenance pack. But on driving floor the throttle and I hear an irritating pinking type sound. Hold the throttle steady at any speed and nothing there.
The dealer took it out, eventually could hear the sound but had no idea of cause. Its booked in for next week (earliest they could lend me a car) But I am concerned. Some say their car does same. Others never heard it. Either way I am not happy and not sure what more I can do.
Has anyone got one? Any pinking type noise?
I have driven diesel cars for 10 years and never experienced this

blueboy2001 · 15 Jan 2007 at 20:56

Common rail injectors can make a sound a bit like pinking, sometimes its a sign they are on their way out but I guess some are just noisy. However, if its at full chat I'd be having a close look at the turbo, which is a known issue with the 320d. Any sort of imbalance on the impeller will make a strange noise.

Is it worse when cold? Common rail injectors are usually at their noisiest when the engine is stone cold (left overnight) and you start it and raise the revs to just above idle speed. Most CRD injectors will make a noise when cold, but should settle down after a minute of two.

NickXX · 15 Jan 2007 at 21:08

What does pinking sound like? Have you tried using injector cleaner?

AnastieByte · 15 Jan 2007 at 21:24

It is worse when cold but not that much worse. My first thoughts were a manifold leak but less sure now. As for the turbo I am aware of the problems but thats why I took out a robust warranty

Lashout_UK · 15 Jan 2007 at 21:28

Pinking manifests itself as a light rattle under engine load, increasing with severity if the problem worses or load increases.

NickXX · 15 Jan 2007 at 21:33

AnastieByte said:
It is worse when cold but not that much worse. My first thoughts were a manifold leak but less sure now. As for the turbo I am aware of the problems but thats why I took out a robust warranty

Any unusual smoke or loss of power? As it's under warranty, I would throw the keys at your nearest dealership and get them to worry about it.

austinpowers · 15 Jan 2007 at 22:08

My Astra 1.7DTi pinked, or at least that's what it sounded like, but i've been told dervs can't pink :confused:

sablabra · 15 Jan 2007 at 22:25

What is pinking??? :confused:

Malachy · 15 Jan 2007 at 22:26

NickXX said:
What does pinking sound like? Have you tried using injector cleaner?

best discription for pinking sound is the sound of someone dragging a bike chain along concrete

Malachy · 15 Jan 2007 at 22:27

austinpowers said:
My Astra 1.7DTi pinked, or at least that's what it sounded like, but i've been told dervs can't pink

from what i gather they cant although i am no derv expert.

pinking is pre ignition basically the mixture igniting before the spark arrives due to heat and compression in the combustion chamber, this is how dervs work....................... the fuel ignites by heat generated by compression (hence silly high 19:1 etc comp ratios on dervs) there is no spark

edit: got confused i have explained detonation...............

this is pinking courtosy of dave walker
"this is the mosty common noise of all, and it produses a light metallic clinking sound. Pinking is actually caused by the ignition being far too advanced. What happens is that the pressure rise in the cylinder occurs too early and the piston rattles against the bore as it goes over tdc. This is mechanical rattle and has nothing to do with combustion. Pinking at light load and low speed isnt an engine breaker, in fact it is quite harmless as long as it is not allowed to continue for too long."

where as detonation is
"This isnt a noise you have to put up with for long, very soon after it appears pre ignition will kill an engine stone dead.
Pre ignition means the fuel and air mixture start to burn befopre the spark arrives. This is caused by something in the combustion chamber getting hot enough to ignite the fuel mixture. Often this is spark plugs overheating which is caused by having wrong grade plugs or by having too advanced ignition/weak fuel mixture."

blueboy2001 · 15 Jan 2007 at 22:31

Pinking is the noise made by an engine when the fuel air mix ignites too early when the engine is under load - usually caused by the timing being too advanced or poor fuel. Also known as knocking or detonation.

Diesel engines can't pink, but they can make a similar sound for a variety of reasons. Sounds like empty milk bottles jangling against each other.

Faithless · 15 Jan 2007 at 23:35

I'd get your Cam sensor checked out, although this would likely be logged by the ECU. If it can't tell the ECU where the cam is positioned the ECU will be relying on the signal from the crank sensor only. Whilst this won't be doing any harm now its better to get it sorted quickly. Another area to consider is a faulty MAF.

Malachy · 16 Jan 2007 at 15:42

Faithless said:
I'd get your Cam sensor checked out, although this would likely be logged by the ECU. If it can't tell the ECU where the cam is positioned the ECU will be relying on the signal from the crank sensor only. Whilst this won't be doing any harm now its better to get it sorted quickly. Another area to consider is a faulty MAF.

why would it have a cam sensor? are they sequential injection or something?
as i said above i know nothing about the common rail dervs really again do they use maf?

Faithless · 16 Jan 2007 at 23:03

Double post.

Faithless · 16 Jan 2007 at 23:04

Malachy said:
why would it have a cam sensor? are they sequential injection or something?
as i said above i know nothing about the common rail dervs really again do they use maf?

They have a MAF and a CAM sensor, crank sensor, LPF and HPF sensor.

The Crank sensor works on a variable reluctance principle which uses the disturbance of the magnetic field which is set up around the crank sensor caused by the rotation of a steel ring (reluctor) target attached to the crank shaft. If this signal is not availble, the ECU will not fire the injectors.

Although this system also relies upon an accurate position of the cam the engine can still start with a cam sensor failure but it has failed to note the cam position which in turn can lead it to sound 'pinky'.

They also have a MAF primarily to aid the engine sub 2krpm and to communicate with the Low Pressure Fuel sensor.