ZD30 OMFG

[Colinl]

Hi All, Got me a funny case of engine doing a muffle pop every time I turn her off, I've tried locating it but to no avail. sometimes loud sometimes quite no patterns as to how loud it is.
Also runs fine up to 3500rpm when boost cut kicks in and the power loss is a prick going up hills overtaking toyotas but its fine underneath that.
Has anyone had similar of can share some wisdom on this funny issue?

Cheers!
Beers......hmmm

[Crash bandicoot]

Maf sensor most likley give it a clean. when i say most likely we hope its only the maf.

failing that injectors

[Colinl]

Hi sorry I forgot to mention its in a 2003 D22 Navara. Not CRDi.
I think the motor has a MAP sensor but i'll give it a clean and see it it stops the power cut,

The little pop at the end of each drive sounds like its coming from the engine more than the exhaust which confuzzles me.

[3VILC]

Welcome to the ZD30 world
Mine is currently leaking oil from the intercooler, a good sign that the intake is coked up with EGR crud causing overboosting. Mine is also the DI version and yup they do have a MAF sensor, had mine cleaned when the injector pump was replaced before I brought the truck, although one would've thought they would've cleaned out the intake while it was off too :\

Does anyone know how the boost cut works on these? Since there don't appear to be any boost reference lines on the intake how does it know its overboosting? (Have looked for one to plumb boost gauge too). I think mine is boost cutting too. You can hear it spool up very quickly then go silent and truck doesnt pull as well, tho with gentle acceleration it seems ok. Must get boost and EGT gauges setup so I can see what its doing. Have been driving it very gently since noticing intercooler, brought it to tow my bush truck but it won't be doing that until I get it running properly now

[Crash bandicoot]

yeah most of nissan's engine use MAF's.
From memory the ECU has a predetirmend set of perameters for the boost given by a potentometer type sensor on the injector pump.(or accelerator pedal if it's a fly by wire) .

Then using such things as temperature reading, air flow resitance from the MAF, engine speed, accelerator position blah blah blah the ecu refers to the pre programmed map and calculates fuel etc.

[tweake]

unlike the patrol/teranno the navara zd30 doesn't have maf or variable turbo. thats why they don't blow up as often.

power drop at 3500rpm is not boost cut. thats just normal fueling. they tend to have a 3000-3500 rpm power band.

the pop at engine shut off could just be the noise from the intake butterfly. tho thats usually more of a clunk.

3VILC, on patrol's the map sensor does over boost @~30psi but what your getting i think is a loss of boost. the boost drops right off and egt's skyrocket. no idea why they do that, but people use dawes valve to stop the ecu from controlling the turbo.
plenty of info on patrol forum.

[Crash bandicoot]

TO clarrify the situation if you have a NON intercooled navara with a ZD30 the aluminium J pipe from the turbo has the MAP sensor affixed to it.

The Intercooled versions the MAP sender is affixed to the turbo side of the intercooler tank.

the ZD30 patrols have a traditional MAF between the Air filter and the turbo intake Thus have never had the piston cracking detonation boost spike issue.

From what the aussie forums are saying the fact that the Map sensor on the J Pipe/intercooler is under direct pressure from the turbo charger and supsetable to contamination and build up from oil residue is the reason for the engines running like dogs balls before self destructing.

[tweake]

TO clarrify the situation if you have a NON intercooled navara with a ZD30 the aluminium J pipe from the turbo has the MAP sensor affixed to it.

The Intercooled versions the MAP sender is affixed to the turbo side of the intercooler tank.

the ZD30 patrols have a traditional MAF between the Air filter and the turbo intake Thus have never had the piston cracking detonation boost spike issue.

From what the aussie forums are saying the fact that the Map sensor on the J Pipe/intercooler is under direct pressure from the turbo charger and supsetable to contamination and build up from oil residue is the reason for the engines running like dogs balls before self destructing.

what a load of crap

in the patrols the CAUSE of the piston cracking is the MAF which gets contaminated and causes boost spikes and dropping into limp mode.
the map sensor on the intercooler does nothing apart from over boost protection at around 30psi (fat lot of good that does!).
the MAF sensor runs everything, fueling, boost and egr. the common rail engines use MAP to run the turbo and maf for fuel which is a much more reliable setup.

none of that applies to the navara. they don't have an intercooled zd30, don't have maf, no variable turbo (so no boost spikes/drops) and a dirty map sensor just makes it go slow but not blow up.

[Crash bandicoot]

On a seperate note.....

why do you think the statement....

The Intercooled versions the MAP sender is affixed to the turbo side of the intercooler tank.

is a sentence on it's own, apart from the rest of the paragraph.

It refers to the location of the MAP on the ENGINE.
Not what ENGINE is in what VEHICLE.

MAF measures air volume that's all it does. The more volume the more airflow, It does this with a resistance circut.

MAP sensor measures absoulute pressure, whether under pressure or vacuum . The more vacuum the more load, the more air the engine is drawing.

they are purely a method of measurement.

nothing to do with governance of the engine by it self.

[tweake]

i had to double check, map sensor is on engine side of intercooler not turbo side.

but i guess i'm just feeding a troll here.

[Colinl]

Checked the Mass Air Pressure sensor today (Aka Boost sensor written on the sensor itself) filthy as shit, hooked the end up to sensor cleaner and gave it a hows your mother.
MAF sensors on the patrol spec ZD30 detect air flow through a hot wire which gets filled with crap and then the engine going nuclear and alot of people get hurt.

Pretty sure the Navara spec ZD30s didnt suffer such a horrible fate and went more like a mk.80 bomb than a nuke.

Thanks tweak for the advice on the 3500rpm thing, will change gears and stop ringing this poor motor to death then! (although mud bogs and hill climbs don't let you change gears in a manual as easy!)

[lax2wlg]

but i guess i'm just feeding a troll here.

Is that your way of saving 'I lost the argument' ??!

[churchill]

I'm splitting hairs again.

MAF (Mass Air Flow) measures air mass going into the engine, not volume.

MAP (Manifold Absolute Pressure) measures the pressure/vacuum of the intake manifold and using engine rpm and air temp the air mass is calculated.

[lax2wlg]

Since I find modern diesel engines scary and have nothing to add, Maybe I shouldnt be such a troll myself. There, I said it. Ahhh, feels good to admit defeat.

[3VILC]

Thanks for that tweake, I knew there seemed to be a few variants of the ZD30 but wasn't sure what belongs to what. Mine is in a JDM terrano. Which appears at least to be a similar/same setup to the patrol nuke model hence why I've been going easy on it.
The info I've found seems to be as mentioned about dirty MAF wire give incorrect reading causing overfuelling, which mine is not as it was cleaned and have checked and still appears clean. The other main issue seems to be (have seen photos) EGR soot and oil vapour mixes in the intake manifold and forms a layer of crud restricting the intake particularly on cylinders 3 and 4 closest to the EGR valve. This supposedly causes overboost (since the ECU doesnt know the turbo is trying to push thru restricted manifold), as well as a rich mixture on cylinder 3 an 4 and lean on 1 and 2.
Will just have to take manifold off and investigate, and fit a boost gauge take-off to the intake somewhere while its off.
Typical Mr. Nissan didn't even appear to use any threaded bungs on the manifold either to allow a pipe fitting to be easily added

[tweake]

but i guess i'm just feeding a troll here.

Is that your way of saving 'I lost the argument' ??!

hell no !

.......... The other main issue seems to be (have seen photos) EGR soot and oil vapour mixes in the intake manifold and forms a layer of crud restricting the intake particularly on cylinders 3 and 4 closest to the EGR valve. This supposedly causes overboost (since the ECU doesnt know the turbo is trying to push thru restricted manifold), as well as a rich mixture on cylinder 3 an 4 and lean on 1 and 2......

yes thats another issue. quite common to a lot of engines these days.
the zd30 tends to blow a fair bit of oil out the breather and nissans bandaid of shortening the dipstick to overfill it with oil makes it worse. so a catch can is a must.

egr valve blocking, turbo variable vanes seizing and the cat blocking up is part of it as well. all gummed up from poor combustion due to excessive egr due to maf not working correctly.

quite a few are now fitting water injection to keep the manifold etc clean.

what surprises me is have not seen anyone fit oil coolers. as piston cooling is the main end result, fitting a cooler to increase piston cooling would the first thing to do.

[Colinl]

Found the pop tonight, it was a noisy butterfly actuator. had me worried it was a leaky injector & the onset of dieseling which is like Parkinsons for me.

http://www.navara.asia/attachment.php?attachmentid=1803&d=1283496816
Not my pic but its the EGR butterfly actuator fyi

[tweake]

thats mine

[Colinl]

its a small internet ha ha.

Couldnt be bothered to pull out camera upload edit etc so pulled a photo off the internet!

Just my luck to get done for plagarism of all places ha ha

[3VILC]

I would almost be surprised theres no form of oil cooling from the factory, nissan used to fit them to quite a few engines, granted they were water 'cooled' oil coolers. I am at least impressed that they fitted a reasonable size external trans cooler from the factory.
I can vouch for the oil, the intake ahead of the breather inlet is coated in it At least the indicates thats where its coming from and not turbo seals.
Really must fit boost gauge, see if it is actually overboosting or just the oil being naturally forced out the joins in the piping. Ive never driven or been in another ZD30 with VGT, so it could be normal, but to me it sounds as tho the turbo spools very quick then goes silent, but could just be the ECU deciding the the turbo doesn't need that much boost after initial foot down, or the turbo is just going quieter at higher boosts. Or a stuffed VGT solenoid/VSV.
Power output seems to be normal and it drives fine, so maybe I am just making a proverbial mountain from a molehill
Tauranga Diesel who I know at least used to be a reputable diesel tuner did all the work on it before I brought it, so one would like think they would've picked up anything major at that time (Replaced injector pump and ECU and cleaned MAF etc)

Its done 250ks, so it probably has more blowby anyway, but my Irish logic was most ZD30s die long before that, its had 1 owner the whole 9 or so years its been in NZ so probably looked after general condition would suggest it has, and its recently been checked over by a diesel workshop, so prehaps its one of the few ZD30s that doesnt turn into a grenage

[Colinl]

I'd vouch for that.

Mines coming up to 300 (290 thou K), no uneven blow by, start first pop everytime & only a slightly hint of a noisy cam chain. Pulls just as hard as a mates D22 nav with a ZD30 & 180 on the clock.

[Trundle]

I hear that replacing the motor with a td42T works well!!!!

[tweake]

they do run water cooled oil cooler. but it has its limits especially in very hot weather. oil-air coolers work a lot better.

[bang-thud-thump]

Never worked on a race car with other than oil to air coolers.
They are the go.