Disco 2 Black smoke

I have had a rebuild done after the TD5 started smoking white smoke and it had been using oil(500ml/800km) over the 2 years I have owned and driving it(66 000km).
Now there is black smoke at start-up and when accelerating and idles rough. Enough power and economical(10km/l). Starts first kick. Hawkeye readings on all 5 injectors were varying up to 7 before the rebuild, but now up to 21 when idling. They can not be all buggered all of a sudden, can they? After reading here about oil in the connectors at the injectors, I am wondering if that could be my problem. The loom plugs are dry at the head plug and at the ECU. I have done about 4 000km since the engine rebuild and getting 10.2km/l average.
Also getting turbo over boost with clear loss of power. When I unplug the AAP the power is back. This happens whether I am at sea level or at higher elevation. Make no change to the black smoke. Why?

ScholtzID said:

I have had a rebuild done after the TD5 started smoking white smoke and it had been using oil(500ml/800km) over the 2 years I have owned and driving it(66 000km).
Now there is black smoke at start-up and when accelerating and idles rough. Enough power and economical(10km/l). Starts first kick. Hawkeye readings on all 5 injectors were varying up to 7 before the rebuild, but now up to 21 when idling. They can not be all buggered all of a sudden, can they? After reading here about oil in the connectors at the injectors, I am wondering if that could be my problem. The loom plugs are dry at the head plug and at the ECU. I have done about 4 000km since the engine rebuild and getting 10.2km/l average.
Also getting turbo over boost with clear loss of power. When I unplug the AAP the power is back. This happens whether I am at sea level or at higher elevation. Make no change to the black smoke. Why?

Click to expand...

Hi when you unplug Aap sensor boost is limited to 1bar

Have you been messing with the turbo?

Boost modular is by the turbo and is cheap enough to replace and easy to fit I would start looking there first...

It's worth changing injector harness if it hasn't been done go for a Leoni one from island 4x4 it's same as genuine..

If it starts first kick like you say then in my opinion I wouldn't of thought there is much wrong...

Injector balancing in the 20s isn't right make sure they timed everything up properly

I found a small crack in the small pipe to the waste gate actuator but after I sorted it out there was no noticeable change.
I have not touched the turbo.
I have to check the cam timing first before changing electronic sensors. I changed the injector harness, MAF and turbo modulator(All non-genuine) about 70 000km ago.
At start-up it run smooth with readings of 3 on all injectors, then after about 10 seconds it is uneven and all the injectors hop around up to 17 to 21.

Black smoke would indicate and imbalance of fuel and air.
Air filter clean?
If the MAF isnt genuine its probably already dead - Only use genuine/VDO/Siemens.

Are the any splits/de-laminated boost pipes? Is the intercooler leak free?

EGR still fitted? If so the inlet manifold could be gunked up with muck. Clean the MAP sensor too.

Those injector balances are very very high, it should be more like -/+ 5. Have the injector seals been replaced? Could be the issue.

Not relevant to your issue but Black Smoke would be a great film title.

The copper washers and O rings have not been replaced. Would a leak through the copper not cause the starvation of diesel through pressurizing the common rail and leak of O ring not cause the sump oil level to rise?
The MAP and turbo modulator are non genuine parts.The EGR is gone. The MAF readings are arouynd 50 at idle to 450 max at 3000. Air filter clean. The over boost only occurs when the AAP is connected. Boost get up to 1.25 without it. The intercooler was cleaned during the rebuild. I do not know whether there are any cracks.

At last I had time to check the injector cam timing. I was told by Shaun Hanekom(ex LR mechanic in East London, now private) that the mark on the flywheel side must be the square gap( not the round hole on which it was set at by the engine re-builder) when the hole in the cam holder and the timing mark and two golden links lined up. I would guess that the distance between the square and the round hole on the flywheel would be about 1.5cm. I could not really tell because I was alone and could not see how far the flywheel moved during the time I was turning the engine.
So after all, the re-builder seems to have set the cam timing incorrectly.

I do not want to get too exited, but when I checked the injectors on Hawkeye afterwards, the worst that two of the injectors jumped to was 12, where all of them got to 21 before. Three of them now only get to 5. The black smoke is still visible on start-up but seems a lot less. I took it for a drive after I reconnected the AAP and found that the waste gate opened at about 2.25kPa and then dropped to basically 100kPa and then started building boost again. The limp mode has not appeared yet like before. The rough idling is virtually gone and I do not hear the miss anymore. My ear is not so well tuned to pick up a miss so I could be wrong.
I will see on Tuesday when I am on a long trip again.
Thanks to all for the valued advice.

Sounds like youre making some progress!

Though as a matter of course I would start replacing the sensors with genuine versions, they just work SO much better and last much than the cheapo versions.

Ideally you should replace the injector washers

Has the boost been adjusted?

Still over boosting. I suppose the link on the waste gate must be either sticking at times or the link should be adjusted. I plan to replace the sensors, but I have spent so much already that I want to take a bit of a breather. The leak on the transfer box is my next project.

Try turning the boost down a little at the waste gate. Generally 1.5 turns = 1psi I think

bankz5152 said:

Try turning the boost down a little at the waste gate. Generally 1.5 turns = 1psi I think

Click to expand...

Good point, Std is normally 13 threads visible on the rod. Just in case someone has has a play.

Cheers

Cheers Neilly, couldnt remember the standard threads!

I have not adjusted the waste gate rod, but it could have been done by the re-builder. I do not want to adjust it until I have made sure it is not the turbo modulator that is buggered again, I replaced it with a non genuine part about 70 000km ago.
What will happen if I leave all three small pipes where there are and just unplug the electrical plug from the turbo modulator? Will the ECU use a default value?
I have purchased a pipe to connect the waste gate diaphragm straight to the pressure side of the turbo pipe to see what happens when I bypass the turbo modulator. The confusing part is that there is no over boost when the AAP is unplugged.

13 threads visible.

is the AAP Genuine? If it is not they cheapo AAPs use different tech to get a reading which is not as accurate or useful as the genuine part. Which could be causing your issues.

I do not know whether the AAP is genuine. I have ordered a genuine turbo modulator and will see if that improves things.

Land Rover did not order the part. I have adjusted the waste gate rod, longer by 1.5 turns, over boost still happens.

Bypass the modulator.

As I understand it, the modulator reduces the air pressure to the wastegate to allow overboost. So if you bypass it then the wastegate sees the full manifold pressure and operates immediately it gets to operating pressure.

I tried that but then the manifold pressure only got up to 1.87 and the vehicle felt weak. The waste gate rod is set with about 13threads showing. I am trying to get the engine to run as designed. The new modulator has apparently arrived at Land Rover EL.

I will try the new modulator but I suspect that the non genuine MAF sensor is not performing up to standard. My air flow is very seldom above 350 and the max I get is normally about 431(at 120km/h under medium/high load). I have seen read outs showing 600.