ZD30 Upgrade power options or buy a New Vehicle

[Tony in Tas]

Hi All.

I have owned my Navara ST-R 3.0lt ZD30DDT 2005 since new. It has only 205,000kms and still in excellent condition. Apart from power loss there is nothing wrong with it.!

I need some advice though as general lay person opinions vary greatly and I cannot seem to get a straight answer. The question, buy a new vehicle (won't be another Navara though), or rebuild my engine to increase power and torque?

A new vehicle would be around $65 - $70k so I'm hesitant to spend such large sums.

An aftermarket chip did nothing about 5 years ago but use huge amounts of fuel and blow smoke so the (very reputable) diesel workshop just took it out and couldn't work out why it wouldn't work properly.

It has a 2"3/4 stainless exhaust and snorkel, but for years (past 8-10) I have gradually lost low down power/torque. For 5+ years I can't even pull my boat out of the ramp without being in high range 4WD. Even then it struggles.

Recently, new injectors and replaced 265/75/16 tyres back to standard 265/70/16 helped marginally but not overwhelmingly.

Has anyone had any experience with power increase modifications:
- Replacing turbo
- Installing an intercooler
- Remapping ECU?
- Replacing the engine completely with another brand/manufacturer?

If spending $10,000 - $15,000 would restore or dramatically improve power (hopefully to around 125 - 140kw) and allow a complete makeover (drivetrain and interior mods), I'll very happily keep it.

Recommendations / advice from experienced turbo diesel mechanics or pers that have actually performed these modifications on a ZD30 would certainly be appreciated.

I don't want to do the work myself, so any suggestions on high performance diesel workshops and parts manufacturers also extremely welcomed.

 

[Boogieboots]

Your injection pump may be on the way out. If you can get a scan tool to check the pump timing you can get a lead on that. I have noticed my economy slowly dropping off and I am thinking of getting some new injectors. 340 thousand Kms on mine.
I know what you mean with buying a new bus, it's a lot of cash. My D22 has Aircon, plenty of leg room (for me in the front at least ), diesel, ute and owes me nothing. Even a new inj pump will only be around $4.5k as I recall. Read through the link below, hopefully it helps mate

https://www.baileysdiesel.com/on-highway/nissan-navara-d22-zd30-black-smoke-low-power/

 

[dattorob]

Well mine is pretty good power wise I mean it's no sports car but enough for passing trucks and towing anyway I've only had 2 3/4 " exhaust fitted and opened up the air filter box put a k&n in. Also the usual emissions mods of catch can fitted, block the egr and butterfly mod. I would also do the above but get your intake manifold cleaned its probably properly fouled up thru not having blocked off egr

 

[sparkybg]

1. Check your intake manifold. It gets REALLY clogged by the EGR gases.
2. I don't remember if navaras have MAF sensor, but this is a pretty common reason for low power. It too gets clogged with time, usually sending to the ECU that there's lower amount of air getting into the engine than the real amount. Replace the MAF with new one. It is waiting for replacement for a long time. It usually needs replacement every 100 - 150 000 km.
3. Check your turbocharger. As far as I remember, navaras are with plain old wastegate turbo (not VNT), and the wastegate actuator sometimes deteoriates with time, giving lower pressure, the ECU sends lower amount of fuel, and you get lower power.
4. Check your valves. There are usually other symptoms when valve clearance gets smaller than needed and even zero, but you loose nothing checking it.
5. If nothing helped so far, check your compression pressure. This will give you a pretty clear picture of engine's condition. If the compression is lower than 25 bar, the engine is pretty worn.
6. If compression is OK, then check your injection pump, but I doubt this can be a reason. These pumps are usually in pretty good shape even after 500 000+ km. There are some drop in fuel amount (around 10-20%) with time, but if the pump is not ok, the engine start becomes hard and problematic.

P.S: Also, check if pressure sensor (MAP) is OK. If it is not OK, it switches the ECU to limp mode with similar results.

 

[[email protected]]

at 150000 klm i had a problem with my old navara , loss of power , it eventually slowed down to max 60klm/hr . fuel delivery problem (contaminated enviro fuel ) blocked gauze flter inside tank , also contaminated filter inside the nut that takes fuel line at pump, i changed this .. took fuel cap off tried lung power to blow back throug delivery line ,it was blocked i used compressor, .. check the flap inside throttle body it may be stuck, stays only partially open when high revs. dont force it out of its position you will damage it.. all the previous recommendations need to be checked. Fault code reader is good place to start
good luck

 

[Tony in Tas]

1. Check your intake manifold. It gets REALLY clogged by the EGR gases.

Many thanks mate. And thanks to Boogieboots, Dattorob, and Izzibri for the suggestions. Really appreciate it.
I'll certainly take these to a shop to look at. Hopefully I can find a shop that will go the whole way and check everything 100%..
If all that turns out ok, the next step will be interesting.

 

[tweak'e]

injection pump does wear and that effects the injection timing causing loss of power, especially in low rpm.

intercooler and remap ecu (or decent chip) makes a world of difference.

 

[pol327]

I'm with sparkybg
Check for ECU stored codes
A Compression test to determine if there is enough available.
Turbo boost .... if the boost pressure is low it could be that the waste gate is not seating properly or may be partially stuck open and not closing, more often than not removing the turbo for an inspection to check vane and bearing condition is a good idea.
Is the waste gate actuator getting a false signal and holding the waste gate open.
If the intake is restricted due to deposit build up from the EGR and crankcase breather then this restriction will cause power loss.
Check for the obvious like boost leakage from a split inter-cooler, leaking intake hoses or loose clamps.

 

[Tony in Tas]

Can't thank everyone enough for the advice and recommendations.! Not to mention a phone call from HPD in Adelaide I received yesterday.

In summary the plan is:
- check for air leakage (hoses/clamps/turbo/filter, etc), boost leakage / pressures
- remove manifold and clean thoroughly
- check injection pump and fuel system (lines/filters, etc)
- check pressure sensor (MAP)
- check turbo
- check valves and compression pressures
- replace MAF
- check ECU codes and remap within

Then see if that restores power back to factor levels. If it does (and more power needed), then consider boosting through:
- install intercooler
- install high flow turbo

I think that covers all the recommendations..

 

[ShortyNavros]

I did a wrote up many years ago to clean out the manifold if you're keen, pretty easy to do. A remapped ecu is the best bang for buck power upgrade. Not easy tho as you need someone to socket the ecu, mine has a Rumpig tune and it is excellent.

 

[ShortyNavros]

Obviously your first port of call is the check all the things mentioned above, if you're keeping the car getting ecutalk cable and hooking it up the car can show you heaps of info. If you had a boost leak you should no about it the car whistles like crazy usually. Maybe installing a boost gauge to see if it is making the stock boost of 15-16psi?

 

[sparkybg]

Move "Replace MAF" to the first place - this is simple and easy (2 bolts if only the sensor is replaced, 4 bolts and 1 clamp if entire unit is replaced ). Then clean the intake after it.

Leave "check fuel pump" to the last place, unless "check engine" is active. If it is active, you absolutely MUST read the codes before anything else. Reading codes is a piece of cake - you only need 5cm wire for it.

Check the turbo pressure only after you change the MAF. Low MAF reading results in low fuel, and low fuel results in low turbo pressure.

So, read codes, replace MAF, clean intake, check MAP and then continue with other things.

 

[sparkybg]

Is the waste gate actuator getting a false signal and holding the waste gate open.

Wastegate actuator is controlled solely by turbo's pressure. This is the beauty of plain old wastegate turbos - they might want more RPM to turn on, but they don't need anything else to control them. Also, they last longer.

Anyway, I am pretty sure that replacing the MAF will bring back considerable part of the lost horses under the bonnet.

 

[pol327]

Even plain old waste gates leak or do not seat properly and a worn turbo bearing is enough to prevent the turbo from spooling up properly.
Here's another simple one, have you checked for a restricted or blocked exhaust ?
Check everything possible before replacing anything.

 

[ShortyNavros]

Move "Replace MAF" to the first place - this is simple and easy (2 bolts if only the sensor is replaced, 4 bolts and 1 clamp if entire unit is replaced ). Then clean the intake after it.

Leave "check fuel pump" to the last place, unless "check engine" is active. If it is active, you absolutely MUST read the codes before anything else. Reading codes is a piece of cake - you only need 5cm wire for it.

Check the turbo pressure only after you change the MAF. Low MAF reading results in low fuel, and low fuel results in low turbo pressure.

So, read codes, replace MAF, clean intake, check MAP and then continue with other things.

The OP has a zd30 there shouldn't be a MAF, but there is only a MAP sensor which doesn't get dirty like a MAF

 

[tweak'e]

Move "Replace MAF" to the first place - this is simple and easy (2 bolts if only the sensor is replaced, 4 bolts and 1 clamp if entire unit is replaced ).

no MAF on those engines.

 

[sparkybg]

OK then - no MAF = one less problem to solve.

I have Terrano R20 with this engine - I just forgot if Navaras have it.

 

[sparkybg]

Even plain old waste gates leak or do not seat properly and a worn turbo bearing is enough to prevent the turbo from spooling up properly.
Here's another simple one, have you checked for a restricted or blocked exhaust ?
Check everything possible before replacing anything.

Agreed. But these problems usually come later, not when the engine is "205000km old".

The check of the turbine bearings and actuator is simple enough without removing almost anything, so performing it is always beneficial before doing any complicated/pricey repairs.

I agree also for checking for blocked catalyst converter.

 

[Horatius]

Hi All.

I have owned my Navara ST-R 3.0lt ZD30DDT 2005 since new. It has only 205,000kms and still in excellent condition. Apart from power loss there is nothing wrong with it.!

I need some advice though as general lay person opinions vary greatly and I cannot seem to get a straight answer. The question, buy a new vehicle (won't be another Navara though), or rebuild my engine to increase power and torque?

A new vehicle would be around $65 - $70k so I'm hesitant to spend such large sums.

An aftermarket chip did nothing about 5 years ago but use huge amounts of fuel and blow smoke so the (very reputable) diesel workshop just took it out and couldn't work out why it wouldn't work properly.

It has a 2"3/4 stainless exhaust and snorkel, but for years (past 8-10) I have gradually lost low down power/torque. For 5+ years I can't even pull my boat out of the ramp without being in high range 4WD. Even then it struggles.

Recently, new injectors and replaced 265/75/16 tyres back to standard 265/70/16 helped marginally but not overwhelmingly.

Has anyone had any experience with power increase modifications:
- Replacing turbo
- Installing an intercooler
- Remapping ECU?
- Replacing the engine completely with another brand/manufacturer?

If spending $10,000 - $15,000 would restore or dramatically improve power (hopefully to around 125 - 140kw) and allow a complete makeover (drivetrain and interior mods), I'll very happily keep it.

Recommendations / advice from experienced turbo diesel mechanics or pers that have actually performed these modifications on a ZD30 would certainly be appreciated.

I don't want to do the work myself, so any suggestions on high performance diesel workshops and parts manufacturers also extremely welcomed.

Replacing turbo and fitting intercoolers can make a noticeable difference, but it's minimal and probably won't fix your problems. It's strange the mechanics can't find anything wrong or that it gives no other obvious symptoms.

Assuming they don't find a problem one thing to keep in mind is the modest power/torque of these cars to begin with. Comparable vehicles, from what I know, all go better and faster than the nav. For instance a 3 litre hilux absolutely runs ring around them (and they're not really known for being fast or powerful themselves). It's a shame they didn't have the V6 option in more vehicles.

Though I don't mind this at all, they seem highly "detuned" but I think that enhances their reliability and longevity. Souping them up can be a problem, the engineers that actually design them had all sorts of initial problems getting enough performance out of them to use in the patrol. So starting with a car like this and doing it up to perform beyond its design might be a cheap way to do it, but if you can afford it, a reasonable condition V8 cruiser is the way to go. Then you don't have to worry about it. Way overpriced though.

 

[pol327]

Hi Sparkybg
"Agreed. But these problems usually come later, not when the engine is "205000km old". "
Generally I would agree with that however being a mechanic and working on a fairly varied range of vehicles it is my experience that checking everything before replacing any parts is good practice. Customers tend to be a little irate when you ask them to pay a bill and their issues have not been resolved. Electrical items or parts purchased are non returnable.
My own 2015 D40's turbocharger failed at 18,000 km whilst still under warranty. Never say never and always look before you spend someone else's money. .

Horatious has made a very valid comment regarding modifications to what I refer to as "High performance diesel engines", that is modern high revving diesels.
The reason old engines like 2H, 2L and 3L engines ran forever was provided they where service properly it is primarily due to the fact that they where not "overstressed". Sluggish, slow revving and made from cast iron equals a long life. My father owned a 3L 4runner that did 920,000 km and I very much doubt that you will ever see that from any modern newer high speed, high stressed engines.
The manufactures have invested a lot of money into making a vehicle that performs, is reliable and returns reasonable fuel economy for what they are.
Sure they will make more power but at what cost. Keep tipping more fuel into them and they will keep making more power until they detonate.
I also cannot understand why your mechanic has not been able to solve this one.