LOSS POWER/ sluggish

[Madz]

Hey I’m hoping someone knows what’s going on first time owning. nissan patrol and no one I know has owned one before 

bought a 03 GU 

Put a brand new turbo and Dawes valve all new hoses also as when purchased the previous owner just made a mess of everything so just got the whole thing changed back to stock. 
done a major service changed fuel filter what not. 
 

and this bloody car won’t go more then 35/40km going up hill 

I am sitting on 15psi 

the car literally struggles so much I might as well run up a hill 

I just don’t feel like that’s normal 

what is it. 
I have had 3 mechanics go over it and check everything and they all said there’s nothing wrong. 
something has to be wrong 

also smells a little rich I ran the fuel that was in it nearly empty and filled back up 

driving me insane  

 

 

Edited July 25, 2023 by Madz

[Rumcajs]

How do ya know its 15 psi?

When? Under what acclerator position/load what RPM?

Anyway is it manual transmission? If it is you need to check that that neutral switch is working correctly.

One way to check is to run engine when cold and use so called heat up switch which will bump RPM to about 1200 RPM and then check if moving g/lever of N position will drop RPM to idle.

I'm still curious about those 15 psi and how is it measured?  If you're using e.g ECUTalk sofware it measures engine MAP sensor as absolute pressure that is atmospheric + actual boost. Atmospheric pressure at sea level is around 14.5-14.7 psi, so with let say 10 psi value would be 25 psi, just saying......however ECUTalk software will not read boost/MAP sensor it doesn't support it dipslays static 15 psi or nothing.

There should be no boost if there is no fuel and there should be no fuel if there is no boost.... these thing are directly related.

Diesel engine needs air and fuel to work properly

While engine is idling check that VNT actuator is fully up against stop/adjuster screw and when engine is off it drops down ....

O3 Patrols have vac canister which can leak like a sieve which means no VNT vanes are set to correct position as there is  no vacuum to actuate but that will not give boost.

Next common issue is fuel starvation as ZD30 uses fuel pressure not only for delivering in to cylinder but for timing advance injection too so no fuel no timing advance.....

Explain how is it possible to get 15 psi boost pressure and lack power to go.  

Unfortunately you need to see what engine management sees to be able to diagnose what is the cause:

MAF sensor reading airflow incorrectly?

Accelerator pedal sensor reading incorrectly,

Turbo VNT actuator position, (indicating vac pipes arrangement)

obvious ones : air cleaner, fuel filter/air in the fuel

I've seen common problem with vacuum hoses blowing off or splitting.

Regards

 

 

 

[Madz]

It’s been set at 15psi through the dawse valve and I also have a boost gauge / egt gauge 

The car is a manual I will have a look to see if the neutral switch is working correctly

ill also have to have a look at the vnt actuator ,also do they need to be adjusted as it is a brand new turbo / actuator 

On 7/26/2023 at 9:17 PM, Rumcajs said:

How do ya know its 15 psi?

When? Under what acclerator position/load what RPM?

Anyway is it manual transmission? If it is you need to check that that neutral switch is working correctly.

One way to check is to run engine when cold and use so called heat up switch which will bump RPM to about 1200 RPM and then check if moving g/lever of N position will drop RPM to idle.

I'm still curious about those 15 psi and how is it measured?  If you're using e.g ECUTalk sofware it measures engine MAP sensor as absolute pressure that is atmospheric + actual boost. Atmospheric pressure at sea level is around 14.5-14.7 psi, so with let say 10 psi value would be 25 psi, just saying......however ECUTalk software will not read boost/MAP sensor it doesn't support it dipslays static 15 psi or nothing.

There should be no boost if there is no fuel and there should be no fuel if there is no boost.... these thing are directly related.

Diesel engine needs air and fuel to work properly

While engine is idling check that VNT actuator is fully up against stop/adjuster screw and when engine is off it drops down ....

O3 Patrols have vac canister which can leak like a sieve which means no VNT vanes are set to correct position as there is  no vacuum to actuate but that will not give boost.

Next common issue is fuel starvation as ZD30 uses fuel pressure not only for delivering in to cylinder but for timing advance injection too so no fuel no timing advance.....

Explain how is it possible to get 15 psi boost pressure and lack power to go.  

Unfortunately you need to see what engine management sees to be able to diagnose what is the cause:

MAF sensor reading airflow incorrectly?

Accelerator pedal sensor reading incorrectly,

Turbo VNT actuator position, (indicating vac pipes arrangement)

obvious ones : air cleaner, fuel filter/air in the fuel

I've seen common problem with vacuum hoses blowing off or splitting.

Regards

 

 

 

It’s been set at 15psi through the dawse valve and I also have a boost gauge / egt gauge 

The car is a manual I will have a look to see if the neutral switch is working correctly

ill also have to have a look at the vnt actuator ,also do they need to be adjusted as it is a brand new turbo / actuator 

[Rumcajs]

22 hours ago, Madz said:

It’s been set at 15psi through the dawse valve and I also have a boost gauge / egt gauge 

The car is a manual I will have a look to see if the neutral switch is working correctly

ill also have to have a look at the vnt actuator ,also do they need to be adjusted as it is a brand new turbo / actuator 

 

It’s been set at 15psi through the dawse valve and I also have a boost gauge / egt gauge 

The car is a manual I will have a look to see if the neutral switch is working correctly

ill also have to have a look at the vnt actuator ,also do they need to be adjusted as it is a brand new turbo / actuator 

OK, if it is genuine turbo charger do not touch the adjustment, it is set at factory (Garret0 and can't be reliably set afterwards. I know some people have fiddled with it, my recomendation is don't.

It would be interesting to  note EGTs when under load whilst lacking power as that can point to a problem. If the temps are low that means not enough fuel and if very high means less air however trick is to understand that relationship. 

15 psi boost limit is standard factory setup without Dawes valve so what is the point?  So at what RPM are you seeing the 15 psi boost? 

ZD30 will usually operate around 8-12 psi happilly without you noticing "huge" lack of power you describe. Indeed as strange as it sounds at lower boost around 12 psi the ZD30 seems to have best fuel consumption vs power output but it will start to struggle if pushed harder without extra air comming in which will be indicative by rapid increase in EGTs once loaded easily flying past 600 C (not good). 

As an example I have mine setup with Dual Dawes/Tillix valves and manual overide where I can limit boost to max 14 psi vs top 22 psi in auto/max mode

That will see the same hill climb at 500C + /14psi and slowing vs 380C/19 psi and accelerating. Mind you mine is heavily modified including customized ECU remap.

So let me get this straight:

You have Dawes valve installed as boost limiter?

What controls spool up rate? is it factory ECU vnt solenoid?

I think you could have badly set up boost control but I still don't understand how you can even reach 15 psi then.

If you could list/obtain boost psi vs RPM vs EGTs and Go pedal position vs Air flow meter voltages that would help to pin point likely causes. Thats what I would do in order to narrow down the issues. A laptop with ECUTalk software and USB cable conected to diagnostic interface would help see and log the relevant data. 

Generally speaking Nissan Patrols with ZD30 4 cylinder engine from factory are pretty low on power anyway and do struggle of the line but once above 2000-2500 RPM they improve a bit showing most power around 2800-3000 RPM.  Still nothing to crow about though!

That engine struggles with the design choices Nissan made in lame attempt to control emissions and that pathetic fuel injection control from Bosch makes the things even worse. 

Regards