2.8l TD manual tuning

[Downunder35m]

If the weather finally get's dry next week, I will do some modifications on the fuel and turbo system to improove performance and fuel consumption.
I'm aiming for about 25% more torque in the lower revs and generally more power in the upper mid range for highway driving.
Since chips are still pretty expensive and you often don't know how they affect the engine I wanted to know if there is interest in a little "documentary" of the modifications, incl. pictures.
By doing these modifications you can achieve anything from back to normal fuel consumption to full turbo boost at 14PSI (instead of 4-7) with modified fuel delivery for godd towing even uphill.
Doing it is dirty and a bit time consuming, so if there is no interest I would not bother to take pictures/videos while doing it
Let me know!

[Badman60]

Yeah buddy, document away! I've got the 4D56 engine, but the concepts are all the same and I would love to learn more about this myself.

I've read quite a bit on the Malaysian Pajero forums (those guys mod/tune their engines to crazy levels), and it seems there are a few common tricks to doing the tuning and modding.

One of them is playing with the wastegate actuator rod length, but I have also read that this just introduces the same PSI but earlier in the rev range (which I don't understand) and can be not that great for your engine internals. I would have thought it would just put more 'preset' on the actuator spring allowing it to open easier. Some of them achieve adjusting this rod length by spacing the actuator 'up' with some washers in the mounting bolts. I'm not really into the idea of playing with the actuator rod length.

They also play with the settings in the boost compensator valve, which is definitely not something I'm comfortable with.

Myself, I've just bought a VDO 0-15psi boost gauge, and also a TurboTech manual boost controller (spring and ball design), so that I can 1/ check to see if the boost is at factory settings (have read the springs in the wastegate actuators can go weak over time), and 2/ adjust this back to factory settings, if need be, with the boost controller.

So for sure mate, document away and give those of us with only a basic understanding a decent lesson in the tuning department. Cheers mate!

[Staybeautiful]

You have the thumbs up from me as I would love to see your results, I also have a 2.5lt powerhouse and would love just a touch more power in the old girl. Thanks in advanced for the hard work.

[NAV]

I would like to see this as well. I'd like to see what can be acheived safely

[Downunder35m]

Ok ok, I got it
As soon as the flooding rain stops I will see how far I get.
I will start with the basics of the fuel pump modification and the increase of the turbo pressure.
As mentioned earlier this can be easily done with little modifications to the wastegat actuator and the diaphragm in the fuel pump.
This is a basic setup for an unmodified system. If you are lucky and already got the controller and gauges you can read it just for the fun of it.
I have done these things on other cars before and I noticed by accident a few days ago that my truck has a pretty similar pump and the turbo system is identical.
For all that might be a bit scared :
By adding 3mm spacers between the actuator and turbo housing you will increase the general pressure from the factory default 6-7 to about 12psi at highest load range.
By turning the diaphragm 90? clockwise you will deliver more fuel for the on-boost (take off and low revs).
If you want to go further I strongly recommend that you have something at hand to block the turbo inlet, but anyway :
Under the diaphragm you'll find a star wheel , you don't have to remove the diaphragm, lifting one corner is good enough.
By turning the star wheel 90? clockwise with a small screwdriver you'll add more fuel with less boost. Should only be modified with the turbo inlet open so that you can stall the engine by blocking the inlet.
If you deliver too much fuel you can't turn off the engine with the key!!
This should be done in little steps to a max. of 90? as it also can increase the amount of smoke coming out, which is a sign of a bad fuel mix
Some pumps have a bolt with a locking nut in the middle of the top cover, if that is case on your pump than it can be used to modify the off-boost fuelling. Clockwise higher, counterclockwise lower.
Never had to use it but if you notice a cload of black smoke when changing gears ( getting out of gear) than you might want to lower the off-boost setup.
Hardcore :
By using a thinner plastic spacer in the pump body (or by sanding it down) you will get even more fuel delivered than it would be possible with normal mods. Only useful if you want to run of more tha 12psi or have a free flow 2.5 or 3inch exhaust.
You can increase the fuel load to a certain point by turning the max fuel screw (weird thing with a collar on it) after that you have to shave.
These two modifications should only be done if you have access to a diesel smoke tester and the meter should not read more than 3ppm under the worst you can produce (gear change, full acceleration, simulated load).

That's all for now, the pics with a matching desciption to it will follows as soon as I take my eninge apart, so give me a few days

[Downunder35m]

Ok, sunshine - tools out!
As promised some pictures and more instructions...

First remove the eninge, that makes working on it much easier!
Yes, that was only a joke....
Tools you need :
10mm socket and wrench
phillips head screwdriver - size3
some mineral tuprs and old rugs

Don't try to do this on a warm engine as 1. you might burn yourself and 2. some of the srews might be much harder to get loose.

Step 1 removing of the whole intercooler assembly.
Remove the pipe between the air box and the turbo too.
As you can see on the pic, with that thing in way you wont be able to access the pump.
The pump is that metal thing inside the black "triangle", with the screw coming out of the top.



Here you can see the actuator for the turbo.



Now, with the intercooler removed, you can see the pump much better.
Remove the 4 screws in the corners of the top cover.
First loosen them with the 10mm socket, after that you can use the screwdriver.
Be careful as ther might be some pressure on the spring for the diaphragm, so put a bit of pressure on the cover when removing the last screw.


Sorry, for the bad quality, but couldn't get it better.
In the back you can see a metal"rod" with a thinner end coming out of the pump housing.
This is the fuel screw I mentioned earlier.
Mine is currently not modified and in original condition.
To make modifications to it you have to remover the tamper proof cover over the screw - not easily done when the pump is mounted, so if you want to go there you might want to think about removing the whole pump first.
Under the cover you'll often find a "collar" that is pressed onto the screw.
This is to prevent a too rich fuel mix which would not pass the emissions test.
But that is something I might explain in a later tutorial.


Here you see the actual diaphragm, mine is round and yours might be a square with holes for the screws in the corners, but the next step is the same in both cases.
Carefully lift the rubber from the groove on the underside.
If in doubt, find something to makr the current position.
Now turn the whole diaphragm by 90° clockwise.
Note : I only turned mine about 70° as I could not find 3mm washers, but that is in the next step explained.


When done clean everything up and mount the top cover.
Make sure to evenly tighten the screws and not to overtighten them.

This is a closeup of the actuator, mine is mounted with 2 screws to the turbo housing. Yours might have 3 screws, but apart from needing a washer more it is the same step.
Loosen the screws, but only remove one screw fully !
Be aware that the actuator might be under some pressure on the conneting rod and it is not always easy to get the washers between the housing and the actuator.
Now lift the part where you removed the screw so that you can get the washer between the housing and the actuator.
Put the screw back in and do the same same for the remaining screws.
I had to use thinner washers (2.3mm) as I could not get anything in that size a the hardware store (not mentioning a name here ).
This is the reason why I only turned the diaphragm 70°.
With 3mm you can use a full 90° turn, but if yours is square you should get 3mm washers as you can not turn only 70° and use thinner washers!


In the last picture you see the washers fully mounted.
Again, sorry, that you can't see them properly.



When done check everything again and put the intercooler back together.
It might be good idea to give it a good wash with a bottle of turps first.
If you do so make sure to fully empty the intercooler and to let it dry out in sun, otherwise you will get a bit stink after the first start


All that took me about an hour and no special tools are needed.
Difference now:
The turbo-lack between 1500 and 2000revs is gone.
Engine pulls evenly from 1500 to 3500 without that I could notice the former struggle when going over 2500 revs.
Pulls much better the hills on the freeway now and does not go down when the cruise control is set to 90km/h.
Take off is now almost normal and I don't have to rev the engine to 2000 for a fast get away.
The throttle response in general is different now, but that was to be expected.
You might think that you have to press the accellerator much further down to reach a certain speed, but mho that is just the feeling as the engine now has a complete diffent fuel delivery for the lower and middle revs.
Over all I'm pleased with the outcome but might go for 3mm washers if I find some and adjust the diaphragm again.
Will monitor the fuel consumption with the next full tank and report back- currently the truck was using around 12.5l/100km, but that is with all the extra load of roof rack, winch and the drawers in the back.
Please report back how you truck responded to this simple tweak if you decide to follow my way.

And one last thing : be careful when it's wet. If in a roundabout you almost got the tires spinning and the back end to break out, you will now feel that it is no problem to go sideways when wet.
If you feel that the eninge does no longer go back to idle fast enough or the idle speed is too high:
First adjust the idle speed and if that is not helping adjust the screw on the top of the pump cover - but only by 1/8 of a turn a time, it is a very sensitvie setting.
By adjusting the off-boost screw the fuel delivery cuts off earlier and faster when going off the throttle.
Keep in mind that for serious off road use you don't want an engine that has no breaking power when going down a steep hill!
For everyone that wants to be on the really safe side:
Get a pyrometer to check the exhaust gas temperatur and to make sure it does not go much higher than before the modifications.
Get a pressure gauge for the turbo and make sure not to exeed 14psi.
If you start to modify the max-fuel-screw I highly recommend using a diesel emissions meter (or however you call these things ) and to stay below 3ppm - 2.25 to 2.5 would better though in terms of our nature.
You then will definately need the pressure gauge and the pyrometer too as a too high temperature of the exhaust gasses will also cause much higher burning temperatures in the engine, which won't be too good for the pstons and cylinders over time.
Kepp the recommended 500km intervals for the oil change and use semi synthetic oil if you can afford it, the turbo will now need clean oil, so if you go hard on your toy keep the the oil quality under control.

Depending on the wether I might go for a full test on the weekend, cruising through the Lederderg forest, so wath out for a red one

[Downunder35m]

Tested the setup today on the freeway.
No comparison to the factory standard at all.
The engine now pulls all the from 60 to 100 in 5th gear without struggling.
Good at the traffic light too as now I can keep up with a 50HP Barina
Starting on a steep hill works now without the need the need to rev the engine to over 2000 and shifting gears is much smoother.
Would love to do a fully dyno and emissions test but don't have the money for it at the moment

[chutsy33]

Excellent doco. I have the engine out of my NJ at the moment so will do the rest of the mods before it goes back in. I put the 3mm washer behind the wastegate actuator already as I ready a similar ob the UK pajero forum. POCUK I think its called. They really get iinto modding their pajeros. They also have some great step by step pull down and rekit threads for freshing up the turbos.Thanks again for the great thread.

[Downunder35m]

You're welcome!
But keep in mind that you have to increase at least the lower fuel setting otherwise you will burn too hot and ruin your cylinders.
While you have your engine out anyway it might be good to check the alternator and other stuff for worn bearings or leaking seals.
It's all so much easier when you don't have to climb in your engine bay LOL

[chutsy33]

Thanks for the reply, by the lower limit do you mean the diaphram?

[Downunder35m]

Exactly.
If left untouched imho your boost is too high.

[Downunder35m]

Filled the tank today and the result is good.
Before the modifications I was at about 12l/100km.
Now after the first full tank I'm at about 13l/100km but have to admit that was testing the power of the new setup quite bit.
Done some "low-tech" power testing too :
Have a pretty steep hill in the woods neary and starting at this little bugger in first gear alsways ended in disaster.
Either way you had to keep the revs over 2000 right from the start or you run out of steam before the end.
Don't get me wrong: no problem when your'e on the move, only when you try to start and get up in first gear.
Now I tried it again, first empty and no problem at all - normal start and I kept going at just under 2000revs with no lack of power.
Next run with 4 addidional adults and 3 kids in the car.
Had to get the revs up to about 2500 and needed a second attempt but even fully loaded the car kept climbing.

For the amount of extra power I can use now I really don't mind using a little bit more fuel, and I guess over time my leadfoot gets used to it and the consumption will go down more
Would be nice to hear if anyone else tried the same and what he/she thinks about it....

[chutsy33]

Nearly have my NJ back on the road. Will let you know how it compares with my old NJ. It was untouched but was a bit of a flyer.

[chutsy33]

Nearly have my NJ back on the road. Will let you know how it compares with my old NJ. It was untouched but was a bit of a flyer.

Wow, it really is different car than the old NJ. Only wound the diaphram about 70 degrees and 3mm washers behind the wastegate actuator. Only problem so far is the black cloud that appears behind me when I accelerate. I may back it off a bit as it is doing an impression of an old school MACK.LOL

[Vman]

Wow, it really is different car than the old NJ. Only wound the diaphram about 70 degrees and 3mm washers behind the wastegate actuator. Only problem so far is the black cloud that appears behind me when I accelerate. I may back it off a bit as it is doing an impression of an old school MACK.LOL

I'm very keen to do this but also concerned about more black smoke than I already have. Mind you I am thinking about getting a full diesel service done with my tax return so may look at doing before it goes in and they can fine tune the mix etc.