2012 CRD ZD30 Turbo Low Boost 4psi

Hi All new to this Forum hope I'm in the right section ???

Got a Turbo Boost Issue with my 2012 ZD30 CRD this problem started six months ago where l went away turned the car off restarted and only boosting at 4psi two days later it cleared back to normal 13psi for six months and now same problem.
When l bypass the Vacuum Controller and hook the Actuator directly to the vacuum pump l get 10psi.
I have replaced the following

* All vacuum lines
* Actuator
* Boost Sensor
* MAF Sensor
* 3inch Exhaust
* New Turbo

I have even try bypassing the vacuum system with a Diesel Smart 20psi Pressure Actuator with boost pressure direct from intercooler and only got 2-4psi

Does anyone know a good Patrol mechanic on the Gold Coast ? already had it to two mechanics and they couldn't find anything

Any help would be much appreciated

Cheers Simon

have you checked intake system ( snorkel , airbox , air filter , turbo , intercooler , throttle valve ) , maybe there is a blockage or possibly the throttle valve is staying shut . i have seen someone who has had rags stuffed into the snorkel . if you don't have a snorkel , there is a pipe going from the airbox back into the inner guard and there is a metal flap with sound deadener sponge near the opening of it at the rear of the guard , it can sometimes suck back onto the intake opening causing a blockage . how old is the air filter.
do you have a scan gauge or such . any codes shown up ?

@Simon67 drop by the intro section say G'day tell us a bit about yourself mate.
http://www.nissanpatrol.com.au/forum...-Introductions


Re: your boost issue:

When you bypass the Vacuum Controller (VNT vac solenoid) and hook the VNT Actuator directly to the vacuum pump line(where?), are you currently getting the Max Boost 10psi?
For this funtionality, assume U have still have the VNT vac solenoid electrically plugged in? CRD require this (using the VNT vac sol or not).
With the VNT vac sol as boost controller, are you currently only getting 4psi max boost?
Have you tried using manual boost control (Dawes/Tillix)?
Have you got a boost adaptor fitted under the MAP sensor? and where are you getting boost reference for gauge and when you used the positive pressure actuator (boost ref from where and is it blocked off now)?

Disregard the boost performance when using the Diesel Smart 20psi Pressure Actuator at this stage.

Hi Bidja thanks for the reply

Hi still have the Vacuum solenoid plugged in what l did was take the Vacuum feed from the Vacuum pump off the Vacuum Solenoid and connect it to the VNT Actuator and l have 10-11psi boost ... Return the Vacuum lines to factory and 4psi boost, maybe ECU issue ?
When l was using the Diesel Smart 20psi pressure Actuator the vacuum line was blocked off and pressure line direct from Intercooler boost gauge also direct from intercooler (Y adaptor under boost sensor)
I haven't got a Dawes / Tillix fitted didn't think you needed them on a CRD never ever had boost issues before ?
About to get a Roo Systems Remap maybe that will fix it if ECU issue ?

@Simmon67, how are loading your engine up to determine your max boost 10-11 psi level (bypassing the VNT vac sol)?

You have done the correct test to determine if you can make boost, bypassing boost controller (vac solenoid or manual boost controller eg: Dawes/Tillix). As you realize caution is required when doing this test as you can over boost if not careful. But if no vac or boost leaks are present you should be able to make boost max to 30psi(spike) but need to hold below 15-16psi with stock ECU or limp or damage to stock turbo will occur. I recon you do understand.

As you do make boost (10-11psi) by-passing vac sol, it tends to point towards the vac sol being defective.
But you say, you cannot make boost with Diesel Smart positive pressure actuator. This indicates a possible boost leak as you have closed vac off(as U stated). Check the o-ring under the boost Y adaptor at the MAP sensor. Are U running stock inter cooler and is your cooler in good condition(no oil smears etc)?

I do not think it is your stock ECU but a remap is a good idea. Should fix the boost issue first.

With ECU remap you will most likely run max boost 20-22psi so a manual boost control kit is required. Either Dawes or Tillix, I have used both and currently run Tillix which suits. With Dawes / Tillix, the CRD can run max spool (no needle valve), suggest you install a needle to control spool rate.
You can also successfully run Tillix / Dawes in conjunction with the VNT vac sol post remap(CRD). This is what I am currently doing. Remember though your vac sol may be suspect.

I would recommend you buy a Tillix or Dawes kit (with needle valve) and get you boost under control first before remap (this will isolate VNT vac solenoid).

We can help you if required mate.

As you were running the Diesel Smart 20psi actuator, the diaghram would not compress spring until boost reached 20psi (would have caused limp). For stock ECU the actuator spring is to be 16psi max.

Have you a scan tool(to clear fault/trouible codes), you will need one for when you start moving away from factory boost control. Try disconnecting your battery overnight to force ECU to reset.