OT: Pinking Diesel Engine

I don't know much about diesel, but I expect the injection has to be timed. I think the idea is that air alone is compressed, and then the fuel sprayed into it at the appropriate moment, when the air is very hot.

Maybe the ECU is injecting fuel too early, before the piston reaches TDC. That would have virtually the same effect as the spark plug on a petrol engine firing too soon.

Diesels 'knock' or 'pink' to work, it's what they do. Now whether you should *hear* a noise that sounds like that is another matter.

Have you just had a VW 'fixed' for the emissions?

It all depends utterly on the software and mapping used as to how much of a knock the engine will give. Lean early injection will be more fuel efficient, produce more NOx and pink more.

And since mapping is somewhat of a moveable feast depending on the sensors attached to the engine and their condition, and the software, I would be asking why the EMU was changed.

And what it was changed for...

If this is after a VW 'fix', take it back and get them to put it right. Daughter's 2.0 TDI Golf had similar issues post fix. They first said it was a dirty EGR which they allegedly cleaned, but the problem persisted. I had a chat with the service guy and pointed out it was their fault, and they must rectify it. After further investigation, they allegedly found some soot which was interfering with the operation of a valve or some other bollocks - but the problem has gone away for now. Dealer techs were appreciative of the learning opportunity. Check Honest John for other experiences.

Nope. Nowt to do with VW, this is a Land Rover. The EMU was changed because the original one (which ran quietly) packed up.

I've been looking at car code readers recently thinking of upgrading and one feature mentioned by so is the ability to reprogramme the injectors ( I know not what features can be changed) So maybe whatever programming data for the injectors in your old ECU have not been set up the same in the new one?

I'd be going back to the dealer and "discussing" it with them. Have you driven it enough to get an idea of the fuel consumption and how that compares with before? In my experience degradation in fuel consumption comes with almost anything being sub-optimal in the engine control system.

I really can't see how a new ECU wouldn't be correct in this respect. It might well start off with a base map, and learn the actual engine's characteristics. But this isn't going to take long.

If this engine is of the Duratorque, much of the mapping is carried out at the dealer and there is very little learning.

I believe the pinking the OP hears is the multiple injection times at part throttles. At full throttle this sound should go away.

BICBW

Just wondering if it's doing the engine any harm running it with this slight pinking. I haven't noticed any difference one way or the other with fuel consumption or performance.

Older diesel designs used to knock like the clappers. We've got a bit spoilt by modern ones in this respect. Pity they've not managed to do anything about the stink, though. ;-)

You need to ask Mr Cheerful, hence the cross post. Might be helpful to mention exactly which model Land Rover.

The ignition cannot start until the actual moment of injection. So you first need to get the timing checked. Don't leave it as it can wreck the engine.

Do you actually know how the injection timning works on a modern diesel?

Please tell me why the timing cannot be wrong.

Please enlighten us.

How modern is a Land Rover diesel anyway?

The principal of the diesel engine has not changed since it was invented, it needs correct timing to run properly, and incorrect timing can wreck it.

Can you explain what you infer is wrong with these statements?