td5 disco fuel dramas

hi all im back again with more dramas. please help.
ive got a serious fuel problem with my td5 disco, she is drinking the stuff like i drink beer haha i used to get around 600/650 miles to a full tank but im lucky to get half that now. ive recently had loads of works done to the truck including, new head has the other was pourus, head gasket, injector's are the original ones but have had new copper washers and rubber O rings, fuel pressure regulator done, new in tank fuel pump and ive changed the fuel filter not to mention a new clutch too. im getting no visible leaks anywhere and no fuel is entering the oil or water and im not getting excesive black smoke from rear.
can anyone please tell me where my fuel is going? why im i using excesive fuel? many thanks guys, jon

just an after thought... if id have somehow managed to put a 90/110 td5 in tank fuel pump into my td5 discovery by mistake. would i get false readings? and would it appear on my gauge to be using more fuel than i actually am?? the gauge is ok by the way

jono359 said:

just an after thought... if id have somehow managed to put a 90/110 td5 in tank fuel pump into my td5 discovery by mistake. would i get false readings? and would it appear on my gauge to be using more fuel than i actually am?? the gauge is ok by the way

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You beat me to it. I was going to suggest that the new fuel guage sensor you put in the tank was faulty and it is! I thought perhaps you were basing your assumptions of excessive fuel consumption on the amount of diesel you were putting in the tank but obviously not!

Just a thought...have you also replaced the air filter? Not tried this in a TD5, but in an older (petrol/carburettor not injection) motorbike, a clogged air filter increased fuel consumption significantly...

Worth a try if you've not changed the air filter recently?