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nissan patrol st-l gu3 4.8
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Discussion Starter #1
For the past few months I've been trying to figure out why my patrol has been driving like a slug. Done a 3" exhaust and nads running 15psi. The problem is that its not getting enough fuel, ive changed the fuel filter but still nothing. Anyone got any ideas?
 

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nissan patrol st-l gu3 4.8
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Discussion Starter #3
Had it on a dyno. No black smoke what so ever and also had ray from turbo engineering say the same after taking for a drive
 

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Can you read the MAF meter voltage with an ECU talk or other device?

It could just be dirty or not giving correct voltage causing the ECU to give less fuel.
 

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nissan patrol st-l gu3 4.8
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Discussion Starter #5
Maf has been cleaned. Maf voltages seemed fine I even tried the jdvm, made a little difference but not enough to keep it there.
 

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Discussion Starter #7
No codes. Have an other maf sensor that I'll change within the next hour. Hopefully there is a change
 

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Discussion Starter #8
No luck. Absolutely no change ��������
 

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nissan
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What model ZZD30?

From what I have read on the lift pump modification it could be the solution to getting better fueling.
maybe check how much restriction it has to draw the fuel from the tank, through the fuel filter to the pump.
Steve
 

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Discussion Starter #10
Its an 05 mdl. I have a lift pump sitting somewhere in my cupboard but can't be bothered putting it in coz im pretty sure like every mod I've done I'll be disappointed. Also think lift pump won't do much as its underfueling from idle onwards.
 

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Nissan Patrol GU4 2006 with Cummins ISDE4.5 270HP , 830 NM Engine Conversion
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i changed filter last time, every thing was tight. took a test drive, the power was down ( compare to ...before the filter change). there was a leaking somewhere, it was very hard to identify since it was leaking the air into the system only when the vp44 sucked very hard. with this kind of leaking, you could not see diesel leaked out.....
so i re-checked everything, and at the end, replaced the O-ring of the water detection switch on the bottom of the filter. and re-tight filter, clamps, etc. power came back! from that moment, i decided to install a lift pump which will help a bit. it also help you to fine out where is leaking.
 

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Discussion Starter #12
Did you have noticable power loss from idle onwards or just top end. Mine struggles to even take off in first. Have to ride the living crap out of the clutch
 

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Nissan Patrol GU4 2006 with Cummins ISDE4.5 270HP , 830 NM Engine Conversion
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Did you have noticable power loss from idle onwards or just top end. Mine struggles to even take off in first. Have to ride the living crap out of the clutch
from idle, thus way i felt something wrong from filter change. also i have an ecutalk which showed me the ICV% is too low. ( from normal 50% idle, to 30% after filter change). make sure you tight your filter ( by the instruction is 2/3 turn after it touchs the hand pump, but i found it is not good enough, i always make a full turn. i had 'double clamps on both hoses. if your car has done big kms, then better also replace the hose from the filter. do not use the factory clamp, use a good one.
dont try to drive hard, as it may damage your vp44.

plus, when replacing the fuel filter, also replace the bottom O-ring on the water switch and make it very tight.
 

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Discussion Starter #14
No probs cheers bud will give it a go. If there is no change after this I honestly don't know what to do. Considering conversion
 

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No probs cheers bud will give it a go. If there is no change after this I honestly don't know what to do. Considering conversion
check your air filter as well.
 

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it is necessary to check all air hoses
as well as the vacuum hose to the turbine control
perhaps there is a hole
 

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Its an 05 mdl. I have a lift pump sitting somewhere in my cupboard but can't be bothered putting it in coz im pretty sure like every mod I've done I'll be disappointed. Also think lift pump won't do much as its underfueling from idle onwards.
Here it is important to know/understand how VP44/Zexel pump actually works. It uses fuel and its pressure for hydraulic action to advance timing of the injection and extra fuel comes hard by on those pumps. So what you are experiencing is retarding of the injection which in turns feels like lack of power.

Fitting additional lift pump is an improvement especially low to mid range torque. When Bosch design specs confirm an option for external lift pump you know that Nissan just gave you the barest of minimum.

Mine was the same absolutely gutless off idle , now I have to watch the go pedal as I'm getting a limp at 1950 RPM if boost climbs past 12 psi and MAF Voltage past 3.45V. All I have changed was to add the lift pump.

Cheers
 

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Discussion Starter #18
Yeah will install it tomorrow if I can be bothered. Mine is actually hitting 15psi by 2000rpm luckily no limp.
 

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Hi PlowKing,

I was experiencing similar symptoms to yourself.

Low power especially in the lower rev range, MAF voltage looked OK, no limp even with the boost coming on early, Very low EGTs.

I had cleaned the MAF several times, upgraded intercooler, upgraded exhaust, new air filter and so on so I just figured that was all the little ZD30 had to give.

Stumbled on an as new MAF cheap on ebay which I bought for a spare but decided to chuck it in just to see what happened.

Significant power increase - as in staying a gear higher on several hills I drive regularly staying in 3rd rather than back to second for roundabouts. MAF voltages are now higher and I will need to back to boost off as it is going into limp occasionally.
 

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Hi PlowKing,

Seems the two most likely causes of this have been covered, if you want to make sure its not the Maf, take a reading of the voltages per the threads on how to test the Maf.

To check for blockage of the fuel system, I installed an elbow with a ball valve on the vp44 side of the fuel filter. Hook up a vacuum gauge to that, with the engine running, it will read how hard the vp44 is sucking to get the fuel. After a new filter it should read in the low 3Hg from memory. When you shut the engine off, the fuel system should hold vacuum if all is well.

This is also a pretty good way to check how dirty the fuel filter is so you know when it actually needs changing.

if it does not hold vacuum, I have used cheap brake bleed kits to create vacuum, my $30 kit has a gauge on it as well, don't go over 5Hg as you don't want to damage the vp44.

The lift pump is a great mod but it would be worth while finding out what the problem is first.
 
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