ADjust VNT Actuator-rod, Grub screw and boost-gauge.

[drjohan]

Hello!

New to this forum but an "old" Patrol-owner from Sweden!

I have a few questions for the experts at this forum.

The rubber-bell in my VNT actuator was broken. It didn't take long for me to figure out that the only way to correct this was to buy a whole new turbo. This because Garret wont sell the actuator itself since it obviously is very difficult to calibrate the actuator afterwards. I went with my car and the "new" turbo to the mechanic guy. One week later he called me and told me that "it was difficult to change the whole turbo so I only switched the actuator.." When I heard this I went bananas because of everything I´ve read about calibrating the VNT actuator rod. So here I am, the old turbo with the new actuator.
This is the problem: I know that the Grub-screw is untouched (since it's fixed to the old turbo). Will this make my problem a bit smaller? Can I settle down with just adjusting the length of the actuator-rod or is it mandatory to adjust the Grub-screw to fit the new actuator? (the new actuator is from an identical Garret turbo).

To adjust the length of the rod I need to measure the boost-pressure. How do I measure the pressure? Where is the easiest spot/place to hook up a pressure-gauge?

When adjusting the length of the rod, is it wise to start with trying to reach the factorydefault (i.e. vacuumpressure when the rod is at the Grub-screw, half way and all the way out) or should I start adjusting the length and just take the car for a test-drive after each adjustment?

As it is for now I think I´m getting a few errorcodes since the enginelamp lights up when flooring the gaspedal. Can you tell if the error-code for turbopressure is because it's to high or to low?

Sincerely
Johan Magnusson

[Steve4wdin]

Hi Johan. Firstly The forum asks every one to go over to introductions and introduce yourself first. Where your from what sort of vehicle you have, Than ask as many questions you like.
Secondly by my under standing don't touch the length of the rod. If you are getting fault codes, Disconect battery for an hour or so to clear the faults. Do you have a Boost gauge?. You need to know what the engine is doing before moving things or it could be very expencive.
Steve

[drjohan]

Missed the introductionpart, sorry! All done now!
I do have a Boost-Gauge but really don't know the best place to hook it up, from what I can se there are no ''default'' places to connect the vacuum-hose.
Since I used to have problem with the MAF, I changed it (from a Nissan Maxima 2.0 which actually is the same...) and read the Error-codes and cleared them, after some driving I do get new ones when flooring the pedal.

[Rumcajs]

If you haven't touched the stop screw on the actuator than nothing major should happen to the way the vanes in the turbo get actuated, as long as it (actuator arm) touches the stop screw when engine is idling and is fully down at rest (engine off).

See in the pic where you can attach/connect boost gauge. You'll need some welding skills as well......use 1/4 gas to 1/8 gas (NPT) M&F brass adapter/reducer, drill the smallest hole to the diameter of the fitting (its tapered) than screw it gently in and than silver solder it in the place. If you can't do it just take it to any mechanical/exhaust shop and they'll do it for you.

Now you have a fitment point for boost gauge, Dawes valve whatever either using 1/8 gas T-ee, Y, L, piece and barbs to fit or blanking plug to be plugged when not in use.

See here for NPT screwed fitings (http://www.ifsaus.com.au/page0003.html) examples.
Cheers

[drjohan]

Thanx Rumcajs! I thought it wouldn't be any easier than the way you explained.
Concerning the stop screw i suppose you mean the one fitted on the turbo, then we do think alike - it's no idea touching that one. Then you, as me, do believe that I only have to concern about the length of the rod.

[Rumcajs]

Thanx Rumcajs! I thought it wouldn't be any easier than the way you explained.
Concerning the stop screw i suppose you mean the one fitted on the turbo, then we do think alike - it's no idea touching that one. Then you, as me, do believe that I only have to concern about the length of the rod.

Yeah I'm talking about the stops screw on the turbo which determines how far the vanes lever go. The vacuum piston(actuator) rod/linkage is also adjustable but that probably needs to be tweaked if for example the the lever doesn't make it to the stop screw you might have to lengthen or shorten the rod. That would be my guess but not my favorite job.
Cheers

[drjohan]

The favourite job is to drive my Patrol, not messing around with its mechanics...
The lever do make it to the stop screw, but at this forum there are many thoughts of "how much" it should touch the stop screw. If you read the repair manual there are three different pressures (vacuum) at which the rod should be at different levels. For example at 13.9 "Hg it should be 0.008" from the stop screw, at 9.09"Hg 0.1974" and at 6.69"Hg at the end of the stroke. Since we do believe that I don't have to concern about the stop screw, maybe I only have to care about the first number (i.e. 13.9"hg). That must mean that at 13.9"Hg i should be able to fit a small paper between the stop screw and the lever - right?

[Rumcajs]

Just use feeler gauges instead of guessing but if you want to guess than I suppose paper sheet perhaps is of similar thickness.
Cheers

[Lieney]

Mate. Easiest way would be to measure an existing one to give an idea on how long it should be. Also, I'd be putting that boost gauge in to see what is happening. Anywhere between turbo compressor and engine is fine. Several spots mate and some bee shown already. Or google it.
There is a GU patrol reference document on here you can access once you got 25 posts. Do yourself a favour and provide some info, asks some other questions and download that doc. It has a step-by-step guide on how to do this with out blowing up your engine. Careful you're not running too much boost mate. Go talk with a good diesel joint and you might be able to get some 'free' info from the also.

[Rumcajs]

....Or you could just download it from --> here (http://www.video2000.com.au/zd30/ZD30%20Y61%20Reference%20Document%20-%20Colour.pdf)
That thing is plastered all over the net.
Cheers

[drjohan]

Thanx mate! Read the document, mostly how to adjust the stop-screw after blocking the EGR. Most of the info tell is not to fiddle with the rod-length even if thats what I think is the best for my car.
I suppose there are no other way to fit a boost-gauge other than drilling a hole somewhere at the pressurised tubings, no alteady existing spots right?

[the evil twin]

snip...
I suppose there are no other way to fit a boost-gauge other than drilling a hole somewhere at the pressurised tubings, no alteady existing spots right?

You can buy adapters on Ebay or the Net.
They fit under the factory sensor and are about $50, link to one supplier below
http://www.extremelimitsoffroad.com.au/pods-gauges/gauge-sensors-options/quick-fit-boost-gauge-adapter-nissan-patrol-zd30-crd

I wouldn't buy one for a CRD as the Scangauge option is much better IMHO but each to their own...

[Rumcajs]

Look in any case it should be on your list anyway(boost pipe T -off), cause it is handy and for 2003 model I'd want to add Dawes valve (http://www.3barracing.com/product_8.htm) as well to keep boost spikes under control. The link from "Evil twin" is another alternative but it is not really helping you over there in Sweden.

Look it is not really that hard, get parts than take the turbo pipe off and take to any mechanical garage, they should be able to do this for you. It takes 15 mins. to drill than tap and than silver solder the fitting in.

Other alternative could be to use ECU Talk cable and software (http://www.ecutalk.com/interface.aspx) + laptop/netbook and read the ECU boost signal directly of its sensor. Don't forget the said software displays absolute pressure e.g. actual boost + atmospheric pressure so you need to compensate for that (take approx 14.5 psi off the readout to get boost only pressure) Those cables are available from UK supplier shipped next day.
Cheers