Rev counter not working on 2.5td with manual box

[Britdragon]

Hi,
Just had rear arches done and a service / glow plugs at our normal garage, which also does the regular underseal and extras, but this time a different son has done the service, and unfortunately he left the oil cap off! As other half noticed it on the floor of van the next day! So oil over part of engine, which they have offered to sort out, but I will do it. Maybe the oil will protect it a bit? Anyways the main thing is the rev counter no longer works, and when she mentioned it to the son at the garage, he said it wasn't them! So I have looked at the forums on here, and noticed the photo put up and how to undo 10mm nut and clean out.
I think I have done it? It was a black plastic circular thing with a straight bit of metal in the end, all covered in oil when I took it out. I cleaned and tried to clean in hole, then put it back, and nothing, do not sure where to look next? Don't want to kick off with garage, as they other members of the family are great and very helpful. Happy to learn something new myself, if you kind people can point me in the right direction.
Kind Regards

[Simon Jones]

This is the rev sensor:



All I can think of is that the connector has got a bit oily so you could try giving the contacts a clean (if you haven't already). I seem to recall they are about £100 new, so you could try a second hand one or see if a local Bongo owner would let you borrow theirs to try. Of course it's possible the rev counter itself has failed, but it seems likely to be somewhere in the engine bay.

[Britdragon]

Hi,
Thank you. Yeah it would be good if I could try another one, I will check continuity of cable to check that the obvious of a plug not in. How does the rev counter work? Is there a spinning metal thing in the hole, that passes over the black rev counter unit in the hole? Does the black unit have magnet in it? Just curious how it works.
Kind Regards

[Northern Bongolow]

works on a pulse per rev.
remove the bolt carefully that is missing from simons pick above, remove the wire then carefully pull/twist. you may find fuel or oil is behind it, clean off the sensor and rinse out the hole then re fit. if i remember right there is an O ring seal around the sensor so take care.

[Britdragon]

Thanks. Will try it out again today, maybe didn't clean hole enough.

[Britdragon]

Hi,
I have removed and cleaned the rev counter again today and no luck,