ZD30 Boost low under load

[CrossCountry]

I've got a 2001 ZD30. Just had a new fuel pump installed then I had to install a new head. It's going OK but under load towing a horse float it will go to 15 psi but quickly drop back to 8psi and little power.
I haven't got a Dawes valve or any of the other stuff, just the boost gauge and egt gauge.
Has anyone got any ideas of what could be loosing the boost?
Can the computer be doing that?
Cheers
Greg

[threedogs]

I think the EGR telling the ECU but others may know better,
15 psi is ok mine spikes to 25 psi
Start getting your NADS together ,its then set and forget

[CrossCountry]

Thanks threedogs . What drives the turbo actuator in the nads system to control the boost?

[threedogs]

You control boost with Nads , Best thing you can do especially on the earlier ZD30 , search Chaz Yellowfoot's advice it will answer all your questions.
Can't recommend enough. Has pics etc. EGR block another good mod

[YNOT]

Boost on Patrol ZD30 is computer controlled and under certain conditions the computer will reduce boost to allow the EGR to work, this has the effect of reducing power and sooting up your engine internally. Technically speaking the purpose of the EGR is to reduce NoX emmissions.
Fitting a dawes and needle valve set up takes boost control away from the computer and allows for a more linear boosting, more like a standard wastegated turbo charger. (Patrol ZD30 uses a variable nozzle turbo and vacuum solenoid instead of a conventional wastegate like Navara ZD30).

[CrossCountry]

Thanks YNOT.
When does the vacuum solenoid get a signal from the computer to open. Also, is the vacuum going through the solenoid to the VNT variable with revs or is it related to something else?

[YNOT]

The signal to the solenoid varies constantly depending on revs, load, engine temperature etc, EGR is normally enabled under medium load and revs.

[rochjas]

You control boost with Nads , Best thing you can do especially on the earlier ZD30 , search Chaz Yellowfoot's advice it will answer all your questions.
Can't recommend enough. Has pics etc. EGR block another good mod

Did my NADS today... And the difference in the drivability is fantastic... I was a not sure about this... but now its done I am 1 happy camper :-). My Patrol use to do the same as you CrossCountry... not anymore.. I am getting a nice smooth boost right thru the range...

[CrossCountry]

Thanks for the reply rochjas. Sounds good. Where did you get the instruction from?

[rochjas]

Hey CrossCountry
I used http://www.chaz.yellowfoot.org/Manua...Controller.htm
I had a mate help me today...He has done his own Patrol.... Its not really hard to do once your pointed in the right direction.... Make sure you block your EGR too... My EGT are running 100 degrees cooler now as well. I sourced my parts from the websites listed in the link above and purchased my EGR block from Ebay.... Purchased 10 metres of silicon hose from ebay too...