ZD30 help

Air filter is fine, new one at last service and not been in any real dusty conditions since

No. nothing recent

If only it would jam shut! That’s why we block them.
Most likely jammed open, sending your boost out the exhaust pipe and creating a rich scenario.
Also check the intercooler hoses. If one is loose or splits the MAF is seeing big air flow, but it’s not getting into the manifold, hence over fueling and smoke.
For some reason your engine isn’t getting air.

John,
Good advice, but then someone else will buy it and then he will be on the forum asking all the same questions again.
Under all the electronics and sensors is a basically good diesel engine that is plagued by poor controls and emission control equipment. I wonder how reliable they would be if they didn’t have a cat converter, MAF sensor and Variable geometry turbo, not to mention the destructive EGR system.
Chaz

Chaz thats a pretty broad claim "Under all the electronics and sensors is a basically good diesel engine"

Its all those bits that make it go and in this particular engine makes it not go so its fundamentally a very poor piece of engineering to which people who own them continue to try and make excuses for.

Cheers

John,
I understand what you’re saying, but I think one of the problems with this issue is Nissan and their reluctance to inform people of the cause of their engine failures. Many people say they don’t know, but I suspect they do, but can’t do much about it. I have to think that Nissans heritage in developing good diesel motors should say something about the basis for this engine, but we are entering a new era in diesel technology and it seems that much more development is needed. Just on that, if you look into other manufactures that use Garrett VNC Turbo’s, like VW, Audi, Volvo etc. They have all had similar issues with boost control, which seems to be the root cause of these issues.
Chaz

I'm not a fan of the ZD30, far from it in fact as both Truckster and I are founding members of the anti ZD30 hand grenade association ;-)
But, I feel Chaz is right and it's not necessarily an engineering problem rather than an engine management problem. The engine failures appear to be a result of poor engine control parameters. There are however, some issues regarding the variable vane turbo's with growing reports of turbo failure.
As a rule Nissan engines are top class in design and you only have to look at the RB26 twin turbo Godzilla engine the SR20 turbo 4 cylinder and the VH 45 quad cam V8 Infinity engines. These engines are some the best engines ever built anywhere.
There are a few reports of the Navara ZD30's expiring but they seem to be very rare indeed but then they use a standard wastegate type turbo that never overboosts like the Patrol ones do. Essentially the same engine with a simpler engine management and turbo and in general they appear to be pretty reliable but the caveat is there are far fewer ZD30 engined Navara's on the road compared to Patrols.
Regards Andrew.

Hi Andrew,
Thanks for the vote of confidence.
I have to say I agree with everything you have said, but one. Personally I think I see just as many if not more 3.0Di Navara’s on the road than Patrols. I wonder what the sales figures would be! If there are as many Navara’s sold, then that says something for our theory about the variable geometry turbo.
Cheers,
Chaz