Maciej · Oct 17, 2019

Good morning!

Lately i have noticed that my Discovery 2 (2002, 270k km / 168k miles) is producing a lot more black smoke than it used to. it occurs mostly around 1100 - 2000 rpms, but the engine is working well, fuel consumption is normal, and sounds normal, it uses a little bit of oil, but it can be due some minor oils leaks which i don't really have time to fix, since it's my only car, it also loses a little bit of coolant, but im pretty sure it's leaking through the cap in the head covered by exhaust manifold.
MAF and MAP sensors are new (but it occurs even when MAF is disconnected), turbo, hoses, intercooler and air filter are in good condition, fuel pump has done 5k kms. it also has a blowby, you can see it in the link below.
there is also an oil leak where the breather hose connects to the rocker cover. i cleaned the ECU plug recently.
im guessing it could be head gasket, oil rings or maybe something wrong with injectors.
If it's oil rings, it means i basically have to rebuild the entire engine, am i right?
anyone had this problem before and know how to fix it?

here is a video with the blowby:

Edit: I forgot to mention, the car starts instantly and there is no white/blue smoke when starting nor running, only sometimes when it's very cold.

Cheers, Maciej!

lynall · Oct 17, 2019

Black smoke will be fuel related and nowt to do with a shagged/leaky engine.
Is that video with the engine hot, ie at full operating temperature?

Maciej · Oct 17, 2019

lynall said:
Is that video with the engine hot, ie at full operating temperature?

The engine was hot, but not at operating temperature, the needle was below the sweet spot, i only drove it for 2.5km, but i can repeat the experiment, what temperature should the engine be at?

lynall · Oct 17, 2019

Maciej said:
The engine was hot, but not at operating temperature, the needle was below the sweet spot, i only drove it for 2.5km, but i can repeat the experiment, what temperature should the engine be at?

Simple test is the high orbit test and is very very technical and takes loads of skill to carry out not!

With engine at full operating temperature and ticking over loosen the oil filler cap so its just resting in the filler hole, if the cap stays there rattling around all is good, if the cap goes into high orbit the engine is shagged!

sierrafery · Oct 17, 2019

Replace the depression control valve to rule it out

Maciej · Oct 17, 2019

sierrafery said:
Replace the depression control valve to rule it out

Thank you, placing order right away!!

yfo866 · Oct 20, 2019

sierrafery said:
Replace the depression control valve to rule it out

That's what i call my wallet!

Maciej · Jun 6, 2020

Hello everyone! I hope you are doing well in these crazy times!

Over half a year has passed since I started this thread, but the problem remains the same, my Disco still smokes like crazy between 1200-2000 rpm and the fuel consuption is not ideal (which makes sense, some of the fuel is converted into smoke instead of energy) . I didn't have much time to focus on the problem, but i checked a few things that i thought might be the issue:
-replaced the turbo cartridge (the old one had a bit of sharp play and i had a new one lying around)
-replaced air filter
-checked all the hoses and gaskets from the turbo to the manifold
-replaced ambient air temperature and pressure sensor (the engine works surprisingly smooth now)
-disconnected the MAF sensor to check if its faulty
none of these things really helped. Is there anything left to check?
My next step is trying to set the injectors and i have two questions:
is it possible that the injectors lost their required clearance without anyone touching them?
are there any special tools that you would recommend or some things i should look out for?

Cheers!

sierrafery · Jun 6, 2020

The special tool i recommend is a diagnostic tool like nanocom or similar to take a live data log from a drive to see all the sensor inputs cos the MAP/IAT sensor can be checked only this way, it doesnt work like the MAF but can be the root of black smoke

Maciej · Jun 7, 2020

I put the old MAP sensor back on today, i replaced it (for the OEM one) 2 months before the car started smoking, but it turned out it wasn't the problem i had then, so the old one should be good. I will take it for a test drive soon. When I removed the sensor i noticed quite a lot carbon deposit on it, but i guess it's normal? i still have the EGR installed.

sierrafery · Jun 7, 2020

Maciej said:
i still have the EGR installed.

then that could also be the root of your problem as long as you dont know if it's working or not so a diagnostic tool becomes compulsory or you'll change parts based on guesses... did you at least check if the EGR valve is not clogged or stuck ?... though the best would be to get rid of it

Maciej · Jun 7, 2020

I checked the egr valve and it looked fine to me, but I think I will order the blanking kit anyway, the carbon dirt on the MAP sensor scared me : D
I will also try to borrow a DS150e Delphi from my friend and check the live data

Maciej · Jun 21, 2020

I finally have an update:

I connected the car to the computer, there are no faults, live data from all the sensors seems fine and correction on each injector when idling is 0 (jumps a little when accelerating, the max value was +11 for a brief moment on the 1 cylinder, but i think its still acceptable?), which is a nice surprise.
The only thing that concerned me was that the EGR valve was constantly reading 0% when idling and when accelerating, i ordered the blanking kit and i planning on fitting it tomorrow, i have really high hopes!

Cheers!
Maciej

ironman 2 · Jun 22, 2020

Does your vehicle have a cat? I had similar problems with my td5 and it turned out the cat had collapsed was partially blocking the exhaust. This cause it to smoke badly as the turbo could not build the boost it needed. I removed the cat and straight away the fuel consumption went up by about 5mpg, the smoke cleared, egts dropped and the vehicle ran much better. A blocked cat will also cause a lot of back pressure in the exhaust which could in turn cause more blow by....

Maciej · Jun 25, 2020

Thank you, I will check how the cat looks (if it's possible on TD5 [now I see it definitely is not possible]) as soon as I get some free time!

After blanking the egr, the car runs even better, it has more power at lower rpm and even smokes less, but the problem still isn't gone.
I was wondering if the smoke is caused by something not working properly or by the lack of EGR, but if I understand properly, the EGR blanking kit should not affect the amount of smoke, am I right?

Even though the problem still exist, I'm really happy with the blanked EGR, thank you Sierrafery for the advice!

sierrafery · Jun 25, 2020

If the cat is still there eyeballing it won't help but as said it can hurt bad the engine's power cos at that age it's definitley clogged and you should fit a decat downpipe there or at least remove the pipe and rip out it's internals somehow if you can

Stanleysteamer · Jun 25, 2020

sierrafery said:
If the cat is still there eyeballing it won't help but as said it can hurt bad the engine's power cos at that age it's definitley clogged and you should fit a decat downpipe there or at least remove the pipe and rip out it's internals somehow if you can

+1^

Maciej · Jun 25, 2020

Thank you, as soon as i get my paycheck I will order a decat pipe, i think its time for a new one anyway, because the flexible coupling near the turbocharger doesn't look so good, and they are quite cheap.
Maybe I will even hear that sweet, deep noise accompanied by turbo whistle.

And if that doesn't work, I will mess with the injectors or maybe even take the car to the specialist for the first time : D

Maciej · Jul 8, 2020

Hello!

I have finally fitted the decat pipe, it took much more time and nerves than i expected, because i couldn't remove the beam that is connected to the frame below the front propshaft and I ended up drilling through the bolts, messy process.

Just after fitting, the car was emiting ungodly amounts of black and white smoke and running only on 3-4 cylinders when I pressed the accelerator pedal. Nearby mechanic recommended that i should drive it really hard for a little bit and see if it gets any better.
After a quick drive, almost all of the smoke was gone, but there still is some kind of vibration at excatly 1500rpm. I hope it is caused by the sound from the new pipe, but that just an overly optimistic guess.
The car drives excellent now and accelerates like a dream.

when i dried to blow air through the old pipe there was barely any air comming out, so i think it was really clogged!

Stanleysteamer · Jul 8, 2020

Maciej said:
Hello!

I have finally fitted the decat pipe, it took much more time and nerves than i expected, because i couldn't remove the beam that is connected to the frame below the front propshaft and I ended up drilling through the bolts, messy process.

Just after fitting, the car was emiting ungodly amounts of black and white smoke and running only on 3-4 cylinders when I pressed the accelerator pedal. Nearby mechanic recommended that i should drive it really hard for a little bit and see if it gets any better.
After a quick drive, almost all of the smoke was gone, but there still is some kind of vibration at excatly 1500rpm. I hope it is caused by the sound from the new pipe, but that just an overly optimistic guess.
The car drives excellent now and accelerates like a dream.

when i dried to blow air through the old pipe there was barely any air comming out, so i think it was really clogged!

Happy for you!

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