Td5 injector confusion

So I’ve got a 06 defender that’s been running really poor I ended up changing all the injectors for a set that I know run okay... someone came over and reset some codes but didn’t actually program the injectors and it starts up and smokes bad for a few minutes.. I thought they needed coding before it would start?!

They are coded to the engine, have you checked your MAF is working ok, that might have been the original problem.

It seems to run with the new injectors without being coded tho? Had running and smoking issues... changes fuel pump, copper washers and seals for injectors.. changed crank sensor. New injector harness.. ecu was checked and seems to be working .. air bleed valve and non return on fuel housing...cleaned map sensor.. egr checked and ok...maf had no issues pop up on the laptop...seem to think fuel is draining back somehow because it cranks for ages then will splitter to life and smoke a lot... once it’s warm it only smokes a little bit and you can turn off and it will fire straight back up... only got 46k on the clock.... anyone a wizard with these near Banbury that would come spend a few hours looking at it with a good code reader... obviously I’ll give you a drink for coming

Did you clean the injector seats and use genuine new copper washers and new seals, lots of after market washers are copper coloured steel washers and do not make a good seal, allowing fuel to drain back. They will run without being coded but may have a default running mode like the MAF to keep engine running but at at reduced performance.

Ok thank you I’ll get them coded them properly... I got the washers and seals from a LR specialist so I’m guessing there good as they are a big well known firm... offer is still open if someone wants to earn a drink and code them haha

Made no difference at all.. I’m on the edge of scrapping the 46k engine and buying a higher milage one on eBay... seem to just be changing bit after bit...