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Discussion Starter · #1 ·
Hi everyone,

My vehicle is a 2001 GU 3.0 Auto, I am towing a van of around 2600kg, I have done the NADS except for the oil catch can but clean the MAF sensor, am doing service every 10k and am 20K into our trip around Australia. Lately I have had the turbo and boost gauge jumping up over 20PSI (most the gauge goes to) then dropping down to 5psi up and down, up and down until I back off the accelerator. It has now started to do it with the van not being towed as well. Before this I did not have any problems like this I had a dawes valve installed and it always held steady about 17psi can anyone suggest what the problem might be?
 

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nissan patrol gu4 wagon
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Do you have needle valve to control spool rate, or is the computer still controlling it.
 

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Y2KGUII ZD Wgn
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Do you have needle valve to control spool rate, or is the computer still controlling it.
Certainly sounds like it is still vac solenoid controlled, if not check all vac and boost lines and dismantle the Dawes and check for debris inside.
 

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Discussion Starter · #4 ·
Do you have needle valve to control spool rate, or is the computer still controlling it.
I thought the needle valve was just used to adjust boost level? I did not get one installed as I thought it should just get set at one level and left there.
 

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Y2KGUII ZD Wgn
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Needle valve is used to control max boost.
No it's not really, although it does have a very small effect the more you open it, it is used to control spoolup, ie, I use mine now to add K's to my wm injection tank when on a trip, so if I open the needle valve I still get the same boost (18.5psi) but it spools up slower so it takes longer to hit the 13psi set point I have for the start of wm injection, therefore I extend the life of the tank though the slower spoolup.

Dawes valve controls boost.

I thought the needle valve was just used to adjust boost level? I did not get one installed as I thought it should just get set at one level and left there.
So without a needle valve you are left to the mercy of the ECU controlled vac solenoid and this usually makes the boost jump around like crazy as you describe. If you read the first link in post #3 of the ZD30DI archives "so you bought a ZD30" it is fully explained.
 
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