200tdi horrible knocking sound

I’ve got a horrendous knocking sound coming from my 200tdi Defender (11L engine)
I was doing 70 on the motorway when the noise suddenly started and I lost power.

Please follow the link to see how bad!! Engine Knocking Defender 200tdi - YouTube

Since getting it home I have disconnected the fuel lines from the injectors one by one and found that when I disconnected number 3 (counting back from the front of the car, is this right?) the noise remained but it turned over more easily and I could now rev the engine up. When the others were disconnected the engine was harder to start and would not rev up.

Has anyone got any ideas what has gone wrong

Thanks
Pete

swap injector to another cylinder see if issue moves ,check all push rods and valves are fully opening , it is no3 as you say ,does oil pressure light come on

injectors if faulty can cause khocking as james said check it in another see if it clears up or goes ?
have you a way of checking cylinder pressures ,that would help alot as this will ensure you have equal compression in cylinders ( or near as dam it )
also this will give you a idea on the valves if they are open/closed properly
make sure your not doing any more damage to engine (BIG ENDS) if this is your problem
good luck mate let me know if this helps

Have you checked the oil level?

Hi

Thanks for the help. Swapped the injectors round as suggested, but the noise still seemed to be coming from 3.
So thought I'd better start from the top and work my way down. Took the rocker cover off to find the adjuster on the rocker for the exhaust valve on 3 had totally undone!

All fixed and no more walking to work for the sum of £3.99!

Thanks again
Pete