VW Diesel PD Piezo Injector. (also for non piezo injectors)

[benough]

Well we never knew if it was a dud injector design or the looms fail and short out, killing the injector.

Mine could be refurbished, not too bothered by it...

[Greg Roles]

Refurb is probably a great thing, as I believe they simply fit a second o-ring to stop oil getting into the piezo stack, where the standard injector has only one. My vote is still oil quality, heat, and oil ingress into the piezo stack, but I reckon only Siemens themselves know, and keep it under wraps.

[harlie]

It’s not the loom that causes the failure; the short is internal to the unit injector. The fault codes logged will not indicate which injector it is, and you unplug each injector one by one, trying to start the engine between (on three), when you have the right one unplugged the engine starts (and runs rough). Usually the harness is damaged during the process and it’s policy to replace it, at $130ish it pays to do it even if undamaged while you’re there and the cover is off as apposed to coming back in later.

If it was the loom, the short would still exist after the injector is unplugged

[jazd]

Refurb is probably a great thing, as I believe they simply fit a second o-ring to stop oil getting into the piezo stack, where the standard injector has only one. My vote is still oil quality, heat, and oil ingress into the piezo stack, but I reckon only Siemens themselves know, and keep it under wraps.

OK cool didn't know this. Where did you hear it?

[Greg Roles]

It’s not the loom that causes the failure; the short is internal to the unit injector. The fault codes logged will not indicate which injector it is, and you unplug each injector one by one, trying to start the engine between (on three), when you have the right one unplugged the engine starts (and runs rough). Usually the harness is damaged during the process and it’s policy to replace it, at $130ish it pays to do it even if undamaged while you’re there and the cover is off as apposed to coming back in later.

If it was the loom, the short would still exist after the injector is unplugged

Only on the Bosch /103 system Harlie, the Siemens 125 system is a situation of all 4 are series, as opposed to parallel, where it can't distinguish betwwen them. It won't run on 3 as far as I can tell, was always my plan if one went on the side of the road!

---------- Post added at 03:19 PM ---------- Previous post was at 03:18 PM ----------

OK cool didn't know this. Where did you hear it?

One of the many diesel forums I spend too much time on, can't recall exactly, but it was from the UK.

[harlie]

Only on the Bosch /103 system Harlie, the Siemens 125 system is a situation of all 4 are series, as opposed to parallel, where it can't distinguish betwwen them. It won't run on 3 as far as I can tell, was always my plan if one went on the side of the road![COLOR="Silver"]

Greg, this is how I'm told they are finding the faulty injector on the 125 - both independent VW shops that I spoke to in BNE gave me the same method - cover off, unplug injector 1 by 1 and when you have the right 1 it will start and run. As you know I have the 103, and when it stopped it would restart (only run for 30 sec), so this method was no good for the my 103 because when the faults were cleared it was happy for about 30 mins - when I mentioned to Mike (P & P) that mine started it was met with puzzled look and "oh crap, not seen that before, that makes it interesting". At the time all of the failures he had seen were 125.

What's in series? How can an ECU control individual injectors with an anologue signal if the signal lines are in series? I could be wrong...

[bluey]

Just curious, there don't seem to be any Polo's in the failed injector register. Does that mean they are not so unreliable?