Noisy injector?

[ashfield]

Hi,
Have a tapping noise which appears to be getting louder. Sounds like tappet noise, but a VW specialist has told it it sounds more like an injector.
When the ignition is switched off while driving, noise disappears. Can anyone tell me if this is a good indication of a noisy injector rather than a noisy tappet please?

[thefoolmccool]

What Car
What Engine

[ashfield]

Sorry,
ASZ PD engine 130 tdi.
Cheers

[thefoolmccool]

Well. I have had a noisy injector before, though it wasn't on a PD engine it was a SDi. To diagnose which injector it was, I loosened the injectors one by one until the knocking stopped, this isnt possible on your engine however.

What you could try is to disconnect the electrical connector to each injector one by one very quickly and see if the knocking stops. But check if this is ok before proceding. It should be ok, but might flash engine light or something.

PD injectors sometimes give bother, although I am not familiar with these engines. The pump is contained in the injector and runs off the cam shaft. Sometimes they can wear. Hopefully someone else will help you out.

[ashfield]

Thanks for that.
Whats curious is that the tapping isn't always there. Not usually there when cold, but gets progressively louder as the engine warms up.
Hard to hear at idle, loudest from inside the car at around 1800rpm.
Performance is fine also.
Will check out the idea of disconnecting injectors individually though.