Zd30 starting drama

Hi all, hoping for someone to give a a fresh idea on what might be wrong with my 2014 model wagon. Currently done 75000k issue started about 5000k ago. Started with being hard to start, replace fuel releif valve. 1 week later hard to start and more black smoke than an R600 mack. Replace 1 injector. 6 weeks later hard to start and a little black smoke, replace remaining 3 injectors. 2 days later hard to start and more black smoke than 3 R600 macks put togeather. All work has been done by my local nissan dealer.
Any ideas why it might be buggering up so quick??
Its hurting my pocket bigtime and its the wifes daily drive.
Thanks
Gary.

Is it every start or only from cold?

The injectors and work must be under warranty surely... I would go back and see what they have to say as it obviously isn't the injectors so they have a consumer obligation to assist at least to some extent.

Bad fuel? When was the fuel filter last replaced. Have you replaced it since these issues began?

yes sounds like bad fuel .. maybe the dreaded Rust ! have a look inside the fuel lines and filters .. It has played hell with the Toyotas . replacing the entire fuel systems .. and lines everything .. (its not a nice job )

Gary forget the R600 and go back to old school b model ;) seriosly if it's overfueling you would start with the maf, filters ,rail and sensors relating to pressure .What are the temps doing ?

I had hard starting and it was a faulty fuel filter. hope this helps.

Didn't happen to be a Donaldson by any chance oldbloke as I've had a couple of bad seals with them now using Fleetguard.