Nissan Patrol 4x4 (Africa)

So patrol arrived back from almost 4 weeks in the shop.

There was about 6 jobs to do of which the first was the turbo waste gate. That was apparently leaking and even with the waste gate disconnected was barely making 0.7bar when it should be over-boosting. After they had the turbo off apparently there was no issue with the waste gate so for a small fortune the turbo was overhauled as the turbo was stiff and not running smoothly. Bearings replaced and turbo refurbished.

I get the car back and it is doing exactly the same... maybe slightly more eager than before.

So Troll will not make full boost. Not waste gate, not turbo.

They turned up the fuel witch may explain the extra eagerness and the EGT s are running slightly higher. I can now get to +700C (before turbo) on a test drive hammering it up a long hill.

Mechanic says next thing is the injectors and the fuel pump. The changed the fuel filter and I did as well at last service.

Any ideas?

Maybe it is overfueling now and that will melt the pistons!

Biggles....praat met frans bel hom of ry hom kaap toe hy verstaan daai motor. ...pm hom moenie dat ouens wat nie verstaan aan jou kar peuter nie lek jy nie dalk lug op intercooler of so iets nie???

Frans het na my troll vinnig gekyk voor ek Windhoek toe getrek het. Hy het gedink did was die waste gate wat gebrandt het.

I am looking for possible issues. I am stumped. Keep coming back to a leak in the system. If it is not the waste gate...

I am thinking of dropping the fuel back down abit and as I moving back to SA in April letting Frans have it when I get back.

I just hate not knowing what is wrong.

Biggels,
I am a petrol head but the other thing popping in my head is something I have read before on this forum.
Guys was referring to a small filter in the banjo connection right in the diesel pump.
Might be worth searching a bit in that direction before spending some more hard earned money.
Riaan

Biggles, now that the fueling has been turned up, and consequently higher EGT's, is there a lot of black smoke coming out the exhaust when full throttle pushing up a hill?

In my opinion 700 deg C is pushing the limits a bit !! I would prefer to see 650 deg C MAXIMUM. I agree with you to turn the fuel back a bit to keep this under control.

If you are getting excessive black smoke (a tiny bit I think is normal for a diesel ) then I don't think any of the filters are blocked (both banjo and normal diesel filter ), but more that you aren't getting enough air into the motor to feed the combustion. More air will reduce your EGT's too with the same amount of fuel, so I'm thinking you are spot on with your diagnosis. I have a stupid question though..... Hows your air filter? On mine I can feel the power loss as soon as the filter gets to the end of its life, and even a light blow with air to clean it out doesn't really help much.

The next step I would look at is at what pressure does the wastegate open. at 0 bar it may be closed and sealing properly, but may be opening slightly at 0.3 odd bar, which will then prevent the turbo from pumping valuable air into the intake. Your actuator arm on the turbo should have a thread and nut on it to allow one to set the pressure of the spring ( actuator). I cannot recall now which way to turn the threaded rod, but there are some posts ( may be on the Aussie forums though ). If you have a boost gauge, what pressure is it registering? I would then increase/decrease the actuator shaft length by half a turn and do a run, see if there is any improvement, and increase half a turn at a time till you get the better response..... HOWEVER..... DON"T OVERBOOST !!! So a boost gauge to ensure you are not pumping 1.5 bar into that motor is ESSENTIAL !!!!

Frans may be able to assist you here with this, but if there are no air leaks on the air plumbing to the motor then it can only be dumping that air into the exhaust..... Keep us posted on the outcome!!!

Bruin Beer wrote:Biggels,
I am a petrol head but the other thing popping in my head is something I have read before on this forum.
Guys was referring to a small filter in the banjo connection right in the diesel pump.
Might be worth searching a bit in that direction before spending some more hard earned money.
Riaan

Checked that. Mine does not have the strainer fitted.

ricster wrote:Biggles, now that the fueling has been turned up, and consequently higher EGT's, is there a lot of black smoke coming out the exhaust when full throttle pushing up a hill?

In my opinion 700 deg C is pushing the limits a bit !! I would prefer to see 650 deg C MAXIMUM. I agree with you to turn the fuel back a bit to keep this under control.

If you are getting excessive black smoke (a tiny bit I think is normal for a diesel ) then I don't think any of the filters are blocked (both banjo and normal diesel filter ), but more that you aren't getting enough air into the motor to feed the combustion. More air will reduce your EGT's too with the same amount of fuel, so I'm thinking you are spot on with your diagnosis. I have a stupid question though..... Hows your air filter? On mine I can feel the power loss as soon as the filter gets to the end of its life, and even a light blow with air to clean it out doesn't really help much.

The next step I would look at is at what pressure does the wastegate open. at 0 bar it may be closed and sealing properly, but may be opening slightly at 0.3 odd bar, which will then prevent the turbo from pumping valuable air into the intake. Your actuator arm on the turbo should have a thread and nut on it to allow one to set the pressure of the spring ( actuator). I cannot recall now which way to turn the threaded rod, but there are some posts ( may be on the Aussie forums though ). If you have a boost gauge, what pressure is it registering? I would then increase/decrease the actuator shaft length by half a turn and do a run, see if there is any improvement, and increase half a turn at a time till you get the better response..... HOWEVER..... DON"T OVERBOOST !!! So a boost gauge to ensure you are not pumping 1.5 bar into that motor is ESSENTIAL !!!!

Frans may be able to assist you here with this, but if there are no air leaks on the air plumbing to the motor then it can only be dumping that air into the exhaust..... Keep us posted on the outcome!!!

Air filter is a valid point. Never been changed by me and gone 2 services now without changing it as it is never in stock/ or stocked where I get my supplies. I will see to that ASAP.

The waste gate is completely disconnected. I get marginally better boost with it disconnected and the line plugged.

700C was MAX on a test run. I will be turning the fuel back.

P.S. I have the madman with boost pressure and EGT so hopefully not damaging the engine.

ricster wrote:Biggles, now that the fueling has been turned up, and consequently higher EGT's, is there a lot of black smoke coming out the exhaust when full throttle pushing up a hill?

In my opinion 700 deg C is pushing the limits a bit !! I would prefer to see 650 deg C MAXIMUM. I agree with you to turn the fuel back a bit to keep this under control.

If you are getting excessive black smoke (a tiny bit I think is normal for a diesel ) then I don't think any of the filters are blocked (both banjo and normal diesel filter ), but more that you aren't getting enough air into the motor to feed the combustion. More air will reduce your EGT's too with the same amount of fuel, so I'm thinking you are spot on with your diagnosis. I have a stupid question though..... Hows your air filter? On mine I can feel the power loss as soon as the filter gets to the end of its life, and even a light blow with air to clean it out doesn't really help much.

The next step I would look at is at what pressure does the wastegate open. at 0 bar it may be closed and sealing properly, but may be opening slightly at 0.3 odd bar, which will then prevent the turbo from pumping valuable air into the intake. Your actuator arm on the turbo should have a thread and nut on it to allow one to set the pressure of the spring ( actuator). I cannot recall now which way to turn the threaded rod, but there are some posts ( may be on the Aussie forums though ). If you have a boost gauge, what pressure is it registering? I would then increase/decrease the actuator shaft length by half a turn and do a run, see if there is any improvement, and increase half a turn at a time till you get the better response..... HOWEVER..... DON"T OVERBOOST !!! So a boost gauge to ensure you are not pumping 1.5 bar into that motor is ESSENTIAL !!!!

Frans may be able to assist you here with this, but if there are no air leaks on the air plumbing to the motor then it can only be dumping that air into the exhaust..... Keep us posted on the outcome!!!

Air filter is a valid point. Never been changed by me and gone 2 services now without changing it as it is never in stock/ or stocked where I get my supplies. I will see to that ASAP.

The waste gate is completely disconnected. I get marginally better boost with it disconnected and the line plugged.

700C was MAX on a test run. I will be turning the fuel back.

P.S. I have the madman with boost pressure and EGT so hopefully not damaging the engine.

I have also battled to get the airfilter for my Patrol. I assume you have the same setup (ZD30 airbox)as mine being an aftermarket turbo setup. I have found a cheaper and easily accessible filter option.....see this post

http://www.patrol4x4.co.za/viewtopic.php?f=50&t=5026

I hope this helps !!