3lt nissan patrol

Matthew,

Presumably from your answer you have seen a customer that has had his 3lt blow more than one engine? I feel sorry for the folk that have had the engine self destruct once, but how do you feel for one that has had it happen more than once?

Cheers, Trevor.

Trev, If those people where to explain their frustrations to nissan in swear words!, there would be not one square inch of air space in this country that wasn't Blue!!....lol


Cheers Axle.

So Matthew, what you're saying is the current run of 3.0 diesels will exhibit the same failures as the early ones despite Nissan redesigning the engine?
I have heard second-hand stories of the later series engine destroying itself.
Gerry

To date i have not seen a later series destroy an engine but have replaced several air flow/mass meters due to customers complaining of low power.

Engine design may have helped the situation but i believe the same engine management system is on the later models with no fail safe.

MAtt

sounds like you are happy with your chevy who did it and how much approx

Sorry Carl, I messed something up.
This is the link…….
http://users.on.net/%7Easchulze/ZD30/ZD30%20Y61%20Reference%20Document%20-%20Colour.pdf

And the Patrol Forum….. http://www.patrol4x4.com/forum/index.php

Overboosting will result in overfuelling because the MAF believes there is more air in the engine than there actually is and raises fuel quantitys to compensate .

The oil in the intake is a big problem and yes it causes huge restrictions in the ports of the head.

Keeping your air filter in good condition goes a long way to keep the dirt of the air flow/mass meter in the beginning which is what eventually leads to its failure.

Matt

Hi Matt,
Yes, I agree, but the problem here is uneven air distribution. The MAF tells the ECU how much air is entering the intake system, but not each individual cylinder. The amount of fuel being delivered to each cylinder is equal, so if you have one or two blocked intakes, they will be rich.

Overboosting will increase fuel, but the additional air helps cool the intake and combustion process and doesn’t necessarily mean that it will be rich. I’ve seen more ZD30 pistons crack from excess pressure than melt or have burn holes from excess heat.

Personally I feel that Nissans 40K air filter replacement schedule is poor. It should be more frequent, but in many cases MAF contamination comes from EGR and crankcase blowby.

The ZD30 EGR valve has 4 stages from closed to ¼, ½ and fully open. The ECU controls boost and EGR under certain conditions. Boost decreases, even under load, to increase backpressure and enhance EGR. If the EGR valve jams open, not only is boost pressure lost to the exhaust, but excessive EGR occurs under deceleration. So, not only will you get contamination, but air that has been metered by the MAF will escape through the EGR valve causing it to overfuel.
This is another problem that potentially is a time bomb, because EGR valves generally eventually fail.
Another interesting theory is that oily crankcase fumes make their way toward the air filter and promote MAF contamination when a hot motor is shut down. Fitting an oil/air separator can go a long way to reducing oil in the intake.

first up I would like to thank Chaz for all this info you don't always get this amount of help,it sounds there are quite a few who are in the same boat[Nissan].I would like to know is the 3'' exhaust part of getting the temp down.

Hi Carl,
Yes it is, but it also helps gain a bit of low rpm torque and improves fuel economy. The catalytic converter is designed to retain heat, so removing it makes a reasonable difference to EGT’s and exhaust restriction. Of course removing the cat and blocking the EGR valve is illegal in Australia, but it’s something that these motors didn’t need to have at the time of their introduction.
Fitting a 3” exhaust will also increase boost, so it should be adjusted accordingly. Another interesting little mod is to fit an electric pump to supply fuel to the Zexel rotary pump. Don’t ask me how, but this has reduced EGT’s by an average of around 30C across the entire range. Every little bit helps and it makes bleeding the fuel system a breeze.

Hi flyboy,
I’ve had my EGR blocked for over 30K and I think it’s the best thing I could have done. I instantly gained low rpm torque, reduced EGT’s and my oil stays clear for 10K.
My car now has 107K on it and my intake is clean.
I have done many more mods over the years and most of them were to reduce EGT’s.
I did change my MAF at 100K, just as a precaution, but there was no real need. I monitor all the engines sensors with OBD software and keep a close eye on MAF voltage. I also have a manual boost controller, so my boost rarely goes over 10psi and my EGT’s rarely see 400C after the turbo.
My car still makes 127RWHP, so it hasn’t lost any performance, but it’s much better to drive.

excuse my ignorance but what does MAF and EGR stand for

ow do you block the EGR?

Carl,
Your MAF is the Mass Air Flow Sensor and the EGR is the engines Exhaust Gas Recirculation System. EGR is in essence a part of the vehicles anti-pollution system and doesn’t do much for the motor.

Bonz, the EGR on a 3.0Di is easily blocked by replacing a gasket with a thin plate.
This way it’s virtually undetectable and the ECU needs to see that the valve is electrically connected.
However, if you block the EGR, you must lower boost because without EGR, boost will increase.

next qn, how dio I lower the boost?

Hi Bonz,
That link to the ZD30 Reference Document that I posted above explains it all, but there are a few ways to lower or control boost. The most common is to adjust the VNT actuator limiting screw, by turning it down 1/3 to ½ a turn. This normally limits boost to 18psi depending on the state of the turbo. You can also adjust the actuator rod length too, but you should never shorten the rod. This will determine when boost is made in the rev range and too much at low RPM is dangerous for the turbo and engine.
Of course, before doing any of this you must have a boost gauge and preferably an EGT gauge fitted.

Bonz, if you're after some REALLY good tech info regarding the ZD30 engine then I suggest you join the patrol4x4.com forum
There's some great info there on oil/air separators, boost control using "dawes valves", blocking egr's and a whole lot more.
Regards Andrew.

I'm glad I have a TD6 Troopy.
I just drive it and have none of this crap to worry about.

Hi John,
I know what you mean, but your TD6 has EGR and will suffer because of it. Long gone are the days of 600K plus reliability from a new diesel.
The ZD30 isn’t a bad engine, but its fuel and emission control systems let it down much more than most. I bought the Patrol for much the same reason as most, and even after spending a few grand on mods to overcome the issues, it’s still good value for my money.
I’ve had a great run so far and wouldn’t hesitate to buy another, but I would modify it immediately knowing what I now know about the problems associated with them and how to avoid any issues.

Bonz, if you do what Andrew suggested, it will be an eye opener.