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1999 GU Wagon ST RD28
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Discussion Starter #1
Hi,
Wanting some help from the brains trust on increasing fueling on the electronic VE pump according to boost pressure.
The ECU works fine up to 12psi, but that's where it runs out.
When boosting beyond this, more fuel is needed. Current offerings such as Donator Speedbox, simply provide extra fuelling across the rev range, leading to excess smoke and EGTs when boost is low.
I have been told by Diesel Central that a DC control voltage is sent from the ECU to control fuelling
What Im thinking is if I use the 30psi MAP to control a voltage amplifier, I can increase the voltage to the pump under high boost conditions only.
Was wondering whether @Phdv61 may have some suggestions on what the circuit may look like. Could it be as simple as a transistor and supporting components?

Thanks
 

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NISSAN PATROL Y61 3.0 Di (ZD30) 09/2000
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Hello @brianwood, I don't know your motor, nor its IP.

If I were you, I would start with building a simple acquisition system, to get, on a graph, MAP value ( in volts, but you could convert easily in mbar or psi ) and the fueling line voltage, to see what your Patrol does today, and get a reference.

I suppose 28D means 2.8L diesel, 6 cylinders ? And therefore you have a wastegate turbo ?

Do you have access to a MAF sensor too telling you the level of air flow ?
Addiing more fuel may make sense if you have enough air coming in, otherwise, as you said, you would get smoke and unburnt gaz.

If you know a bit about hw and sw, I would suggest you have a look at the Arduino board, and its IDE software package. It is very easy to acquire/digitize 0-5V analog signals. So getting MAP or MAF in, very simple. Theses boards have high ilmpedence inputs.

To generate an analog signal, these boards are a bit limited, as they can only generate "pwm" output signals, but these can be filtered to become acceptable analog signals. To generate my MAF analog output, I used two RC fitters and an AMP-OP in between to present a low impedance output to the high impedance input of my ECU.

If you need to have a 0-12V output ( Arduino is 0-5V), not an issue. and yes with a few more components, you will be done.

To acquire your pump control line, if it is 0-12V, you will need a 'resistors bridge' divider to make this 0-5V at the input of the micro-controller. A chinese Arduino cost a few $, and a shield, on which you can solder and wire some components to do some trials, less than 2$.

Start with acquiring your MAP an existing fuel control line data.

You are welcome to send me a private message if you need more help.

EDIT : are you sure the pump is not controlled through a 0-12V pwm signal rather than DC ? in that case, you will need to adapt this signal to the Arduino input, and use a digital input instead under interrupt like D2. I have done that for my RPM signal so I can guide you too if need be.
 

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NISSAN PATROL Y61 3.0 Di (ZD30) 09/2000
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I checked the documentation I have for the RD28.
It IS a pwm signal sent by the ECU which controls the pump.
"Intercepting" that signal, and modifying it ONLY in some conditions (high MAP/ MAF value) is not that complex, once you have set a "reference" as explained above, and if you know and understand what you are doing.

It looks like a guy did that job already using an Arduino, and his software is online. I saw it months ago from the top of my head, when I was learning about the Arduino "world".

And it will be much easier anyway than for the VP44 on the 3.0Di ( cost of black boxes is around $1000 Remap a bit les I suppose) for which I gave up from day one. The RD28 ECU can't be remapped in Australia ?


515938


515939
 

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So now I can answer your initial question :
Once you have "instrumented" you Patrol to know the current level of fueling vs boost ( and RPM / Throttle - load ?) you would need to know which parameters are being used if you want to mimic what the ECU does EXCEPT for high boost/RPM for instance.

You will need to acquire all sensors that have a play in the existing fueling, and generate a proper 0-5V pwm signal with which you will control a 12V-MOSFET capable of delivering the right Amps to drive your pump solenoid.
Interesting little project.
 

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Discussion Starter #5
You're a legend Phil. Blokes like you who make this forum amazing!
So, if we're talking pwm and all I want to do is lengthen the pulse under certain criteria, couldn't I do that with a 555 timer?
Am I being too simplistic?
Im thinking that 2 inputs would be useful, MAP and TPS. I think both would play a part in altering the fuelling.
Also, heads up, Im running the same turbo as you controlled via a Digibooster. And my TPS is the same as yours.
 

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Discussion Starter #6
Just to confirm, I don't want to take over the role of the ECU in fuelling at this stage. Just wanting to modify the PWM when going past 12psi and moderate throttle.
 

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Discussion Starter #7
Im going to order an oscilloscope to get started...
 

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NISSAN PATROL Y61 3.0 Di (ZD30) 09/2000
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Yes, I have a dual channel oscilloscope connected to my PC. Bought it 50$ from china/. Works very nicely.
What you need is to "acquire" the existing pwm signal.

And to generate a given pwm signal depending upon the value of MAP, yes you could make it with electronic components but honestly, it will be much much easier with a micro-controller.

I can guide you to use an Arduino and shield to acquire your MAP and pwm signal ( for pwm, you need the frequency used, and the pwm value, and the only way is to measure, the rising front and falling front under interrupt using a micro-controler. ATMEGA is really easy to use and program. I learnt, so anyone can.

I may open a separate post describing what to do, where to buy and how to make it.
It can be used also to acquire RPMs and MAF, to suppress limp modes without remapping. Like I did.

Two years ago, I did not know any of this, and had very reduced electronic knowledge. Software was more or less ok though. But I learnt ... 38 years ago. So I had to get a refresh.
With forums, and the help of knwolegeable people, you can learn very quick. Same with mechanics. I learnt a lot, reading all posts, all problems, all solutions found.

It all starts here : Arduino - Home
And do not hesitate to jump to examples, projects etc... You'll find all what you need. As I did.
But I can help you save time and effort ;)
 

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NISSAN PATROL Y61 3.0 Di (ZD30) 09/2000
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And even if you do not replace the ECU, it means that
- you will start acquiring the ECU pwm signal, and re-send it exactly the same to your IP.
And you will have to cut the wire going from ECU to IP, get it in your micro-controller, and then output the same signal to the IP.
- then, you will decide when to modify the value within your micro-controller by software depending upon criteria you have decided, and alter the pwm order to the IP.

IT is exactly what a 'power box' does by the way.

And It is the same mechanism I have used for my MAF and get rid of the limp modes, using an RPM input.

And keep in mind that the IP has its own limit in the maximum power (grams of fuel) it can deliver. on my 3.0Di 2000, my VP 44 is unable to "generate" more than "37kW" per cylinder or 200HP. I know many different versions exist of that VP 44, which are capable of providing more fueling. I have no idea what yours is capable of.

By simply putting a DC voltmeter on the signal, you'll be able to get the current range used.
( as a DC voltmeter will give you an average voltage of the signal and therefore tjhe % used). If you had the technical specs ( and the range of pwm% which can be used) you would know how much is left for you to use.
 

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NISSAN PATROL Y61 3.0 Di (ZD30) 09/2000
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Good morning, I translated a very short piece of Arduino test code I did to learn how to capture and measure a pwm signal.

Here it is. It still compiles, but I did not load it on a micro-controller to check.
Just to give you an idea of how simple it is to generate a pwm signal ( one line of code !), but a bit more tricky to acquire and measure. It took me some time to get there.

Acquiring MAP requires a few simple lines of code too that I can provide. So no worries.
Enjoy your learning.
Phil.

Rename the file in .ino to be able to read it using the Arduino IDE.
I hope my translation to be clear enough as I document my software code in French usually. of course.
 

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Discussion Starter #11
Im up for it. Arduino has been ordered...
 

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and you need a shield or two too to play with. This will plug on top, and allow you to wire the components you need to do your tests. We'll keep in touch. You'll see, it is fun.
when you are up with it, let me know.
I will transfer to you my graphic software ( open source I modified ).
Also, download the "Processing" open source package.
This will allow you to have your own display and processing sofware on your PC communicating in real time at high speed through USB with your own Arduino software.
 

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Discussion Starter #13
and you need a shield or two too to play with. This will plug on top, and allow you to wire the components you need to do your tests. We'll keep in touch. You'll see, it is fun.
Bought a kit with shield and components
 

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Discussion Starter #14
I'll load up the IDE shortly and start looking at some pwm code...
 

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NISSAN PATROL Y61 3.0 Di (ZD30) 09/2000
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The test code I sent you needs to be modified to run continuously.
Try and find why, and how to modify it.

A clue in the arduino doc :

micros()
[Time]
Description
Returns the number of microseconds since the Arduino board began running the current program. This number will overflow (go back to zero), after approximately 70 minutes. On 16 MHz Arduino boards (e.g. Duemilanove and Nano), this function has a resolution of four microseconds (i.e. the value returned is always a multiple of four). On 8 MHz Arduino boards (e.g. the LilyPad), this function has a resolution of eight microseconds.
 

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and then try to replace the two interrupt routines by one only, making use of the 'CHANGE' option ( changing edge) instead of RISING and FALLING.
 

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Discussion Starter #17
Bought a MOSFET module for Arduino $8.
So now I can generate a PWM signal up to 5A which should be plenty.
My plan is to measure the pulse from the ECU in real-time, generate my own PWM with same dwell, and add extra dwell when boost > 12psi...
 

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This looks fine to me.
Check the IP solenoid voltage though. The Nissan Doc mentions 10V, and your alternator producing 14V or so.
And do not forget to put a fuse on your pwm power line to the Solenoid...

Initially, you need to measure the pwm signal and MAP vs time.
Then, you will cut the pwm wire, put it in your Arduino to measure, and restitute it 'as is'. And check the behaviour of your Patrol is fully identical.

and then will you be able to install a 'modification algorithm', modifying the pwm signal (increasing or decreasing...)
And be careful that depending upon the type of MOSFET, you might get an inverted signal.
Also, make sure your module has a free-wheeling diode connected to its solenoid outputs or your mosfet will not last long.

You'll then be able to do your own VNT management


This is what I use to control the pierburg VNT solenoid :

pwm being the 0-5V pwm signal generated by the Arduino.
EV = Solenoid. with + (12V) and - (MASSE)
Terre _batterie is negative battery

have fun !

516026
 

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Discussion Starter #19
Thanks Phil,
I know the next step maybe VNT control, but baby steps first. Im happy with the Digibooster doing this for now.
This will be a huge coup if I can get this to control fuelling well. I believe the later TD42's have a similar setup, so these guys maybe interested...
Plus a 12mm head can be fitted to this pump, however the ECU alone will not control it well as there is only the AFM for feedback.
Imagine the potential with this intelligent control with a 12mm pump!
 

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Happy with this outcome, and if it can help others out, even better.

In fact, what you are about to do is what 'power boxes' do, but often badly as they only increase fueling, without taking into consideration load, or MAF / MAP value.

Here is one, allegedly adding 25HP, and 40Nm of torque.


They say below to connect it to MAF on one side, and to the pump on the other.
So I suggest you use MAF instead of MAP ( or both), as adding fuel is ok when you have enough air.

If you follow the posts on the Dawes+Needle / Needle setting, you will see that convincing people is not always easy, even when you are bloody right. But eventually thruth comes up like a nose in the middle of a face ( direct translation of a french say).

Someone even said I was a liar ! I am yet to receive his apologies :). But he does not seem to be a gentleman. I can live with that. Funny to me. Like shooting on the ambulance...

If i can be of any help, let me know, and if you experience problems with software, too. Having the right set of tools is essential. I love graphs as nothing replace a glimpse at a curve.
 
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