This is a TD42 Pump in a GQ
Gauze Filter can be found about 20mm under the level of the bolt head.
Nissan Part Number is 14371-R8025A
Bosch Part Number is 14612501016N1
This is from a thread I posted in on outerlimits and was for my GQ, but should be the same on a GU
This "thimble" filter is only about 3-4mm in diameter.
Clean up around the top of the injector pump
Looking straight down from above.
The banjo fitting on the inlet section of the pump is the one that is closest to the front of the engine and has a steel fuel line which runs to it via the gap between the back of the pump and the block. The line that feeds the fitting runs between the pump and the block.
Undo this bolt, and remove it.
There should be enough movement in the banjo fitting to push it clear of the hole it feeds beneath the fitting, or you can just work through the hole in the fitting the bolt came out of (harder).
I have a set of Snap-on dental picks I use for this (I check it every service) but a length of small diameter, stiff wire, with the last 2-3mm bent at right angles should do the same job, or a piece of the stainless backing strip you get when you change your wiper blades is good too ( I save everything)
Now feel down inside the pump, about 15-20mm deep, and try to hook the filter out. It is a stainless gauze filter (approx 3mm deep, 3-4 mm in dia), with a brass ring around the top edge.
Note;I have heard stories that some patrols do not have this filter, but between me and my mates in total we have had 6 TD42's from 89-06, and all of them had this filter.
Clean it out with compressed air and replace it.