Ford Focus TDCI problem

Hello friends, I have a rather weird problem and I would like some opinion before getting more thorough. The case is that the other day I get a Ford Focus in the workshop and the cylinder three fails the compression and we have changed injectors well and nothing. The car enters diesel but it seems that that piston does not burn it, it makes me smoke CV of 2002 thanks before hand

Try one thing, remove the injector cable 1 and measures that Voltage sends the switchboard to that injector. Then measures the 3.
If your voltage does not reach, it may be there will be no whole that it owes and fails.

Or take out the injector out and look to see if it pulverizes well and does not drip.

I hope it serves you, greetings.

Thanks Igryo for your answer we have already found the paste we measured the compression again and there is a leakage for that cylinder the other mechanic the bad greeting and thanks again