Welcome to the Nissan Patrol forum. To post a question and to see less adds on the forum then you will have to register
first. We are an easy going friendly forum so join in the conversations and feel free to ask any questions.
Become a forum sponsor for only $20 and see no adds with faster page loading times and many extras benefits.
I've been at it for a few days now. But it's been an issue for a while now. I've been having a long battle with boost. Read as much as I can but I'm hitting a wall
As mention 2001 GU2 Patrol ZD30 having boost issue.
Dawes & Needle Valve, EGR Block, Catch can, Cross Country Intercooler all installed. 6+ years now
I replaced boost and EGT gauges for better readings. Previous owner installed EGT and a boost gauge that had negative values both was cheapies from the bay. Replaced with SAAS muscle digital series.
Most recent issue is very low boost. 5psi if i give it alot.
- Checked and cleaned Dawes. Added more pressure on the ball no change.
- Turned the needle all the way down (closed) also backed it off in 1/2 turn intervals no noticeable difference
- Cleaned the MAF sensor.
- Pulled the intercooler off, cant see any oil spray, stains signs of leak on intercooler.
- Checked all the hose and clamps from throttle to intercooler to turbo - no stains or signs of leak, no damage or hole I can see.
- I've replaced all 4mm hoses that I know of.
And this is about where my understanding taps out.
- I know the waste gate actuator goes down when I pull the line off it and up when I push it on.
- I also have vacuum from the vacuum pump, not sure how strong should it be?
I need some help on what to check next, as well as how to check the actuator and vacuum pump are working correctly.
- I know the waste gate actuator goes down when I pull the line off it and up when I push it on.
- I also have vacuum from the vacuum pump, not sure how strong should it be?
I need some help on what to check next, as well as how to check the actuator and vacuum pump are working correctly.
Richard, the VNT actuator (you refer to it as: the waste gate actuator), appears to be working correctly.
There appears to be adequate vacuum at the VNT actuator as the rod moves up with vac hose connected and then drops down when hose is pulled off "with engine at idle".
CHECK _ With eng at idle (hose connected /rod up): is the actuator rod / lever resting against the vane limit stop screw.
FYI, Full vacuum at actuator with engine at idle is nom 23"Hg (inches of mercury _ vacuum)
Be worthwhile to use a scan tool and check for any fault codes. Clear them but but first record any if reported?
Are you running a stock ECU?
What was the max boost, if you know the level before current boost issue?
Maybe a limp fault causing problem.
We can test VNT turbo boost response with bypassing manual boost control _ need to check and action above first.
Richard, the VNT actuator (you refer to it as: the waste gate actuator), appears to be working correctly.
There appears to be adequate vacuum at the VNT actuator as the rod moves up with vac hose connected and then drops down when hose is pulled off "with engine at idle".
CHECK _ With eng at idle (hose connected /rod up): is the actuator rod / lever resting against the vane limit stop screw.
The actuator rod does not reach the vane limit stop screw when idling. *After a bit of google to figure out that its not the two bolts on the actuator arm hahah*
Originally Posted by Bidja
FYI, Full vacuum at actuator with engine at idle is nom 23"Hg (inches of mercury _ vacuum)
Be worthwhile to use a scan tool and check for any fault codes. Clear them but but first record any if reported?
I don't have a Auto Diagnostic Scanner, I'll see if i can borrow one locally or I'll pick one up for myself.
Originally Posted by Bidja
Are you running a stock ECU?
What was the max boost, if you know the level before current boost issue?
Maybe a limp fault causing problem.
We can test VNT turbo boost response with bypassing manual boost control _ need to check and action above first.
Correct running stock ECU.
Boost was running at 15psi.
Appreciate the help, eager to get back into it to figure this out.
The actuator rod does not reach the vane limit stop screw when idling. *After a bit of google to figure out that its not the two bolts on the actuator arm hahah*
Good that u sorted out which was the correct screw for lever to rest against lol.
Now to confirm:
With manual boost control (Dawes and needle valve) connected, close needle completely (wind in clockwise):
At idle, is the lever now touching stop screw y/n?
If it does not, connect the vacuum hose from vac supply point (on DI, think it is just under front of intercooler), connect this hose direct to the actuator diaphragm (refer pic: finger on red hose is the place). Lever should now rest hard against the stop screw with engine at idle y/n?
TESTED - Needle valve completely closed, at idle the lever does not touch the stop screw.
TESTED - I connected the Vac supply directly to the VNT diaphragm and the lever does not touch the stop screw. Appears to be the same amount as when to T piece.
I have attached images showing hose locations in case I got this wrong somehow. I also added the Needle/dawes diagram that my system is set up as.
Mudski - no unfortunately this occurred before attaching new boost gauge. Original gauge was not a diesel boost gauge style and needed replacing.
TESTED - Needle valve completely closed, at idle the lever does not touch the stop screw.
TESTED - I connected the Vac supply directly to the VNT diaphragm and the lever does not touch the stop screw. Appears to be the same amount as when to T piece.
I have attached images showing hose locations in case I got this wrong somehow. I also added the Needle/dawes diagram that my system is set up as.
Mudski - no unfortunately this occurred before attaching new boost gauge. Original gauge was not a diesel boost gauge style and needed replacing.
VNT actuator lever needs to touch stop screw.
Can buy a vac gauge from Repco to check vac level in line. I have one connected all time to observe vac on the VNT actuator on the fly (driving)_provides indication of vane closure position.
Also need to check that the VNT vanes have not been clogged up with carbon/soot preventing vanes from closing. Post a pick of the actuator rod showing the thumb wheel adjuster paint marks on it for locked setting position and check that the thumb wheel cannot rotate(eg: lock nut needs to be done up _ refer to my pic posted above of actuator/diaphragm).
Can suck like "crazy" on hose connected to actuator diagram and see if rod will rise (lever to rest against stop). I have a hand operated vac pump for this as my lungs would not like sucking on the hose so hard..haha
If vacuum for both hook ups (needle closed and direct vac hose connection), is above say 13-18"Hg and lever still does not touch stop screw we need to disconnect actuator rod from lever pin to see if the lever can rise/fall freely and should give a slight clang noise as vanes open / close to their limits. Could also indicate someone has changed the actuator thumb wheel setting (all in good time). FYI _ Can also undo the two nuts holding the actuator diaphragm in place to help remove lever from rod pin/pivot. Need to tie a piece of fishing line to the e-clip at pivot and secure the line to A/C hose or similar so not to loose clip when removed (trust me it will fly).
I saw something from the suppliers of Dawes and tilling valves the other day about these systems starting to play up.
And simply. The age of the hose its deterioration.
So it's suggest before to fiddle too much just replace all the vacuum hoses.
Probably $20 worth.
Imo they are very simple, set and forget setups.
So if your seeing a failure I doubt it would be the valves, especially if your using filtered air on your needle valve.
As Kallen says, do agree most of the times it is vacuum failure that cause the poor operation of Tillix or Dawes manual boost control setups.
Reason for getting the vac gauge from Repco, to check vacuum level in system. Be interesting, before u start changing out hoses, check the full vac at supply take off and then T the gauge into the vac hose just before actuator(measure level at idle). As mentioned full vac is around 23"Hg at supply point and at the actuator with rod fully up is around 12-14"Hg.
Reply With Quote
Originally Posted by DickieO
