Thread: Black soot coming from exhaust of D2 V8

good work

Originally Posted by biggin

I ended up replacing only one of the O2 sensors, as the other side looked much more difficult to do, and it made a noticeable difference. The engine seems much more responsive and although I haven't made it out of the driveway yet, the soot deposit from the exhaust has ceased.
Really looking forward to the weekend when I can take it for a long drive. I'm reasonably confident it will perform much better than it has for a couple of years now.

Biggin you talking about the drivers side one? yes a bit harder to do, If I remember, I found if you come from the front of it doing "a double jointed arm lock" over the front prop shaft you can swing a spanner at it , there's not a lot of swing space to crack the thread .

Cheers Mario

Yes, correct, the driver's side one looks more difficult. I ran out of daylight so didn't attempt it, but the existing one seems quite responsive so I think I'll leave it there and keep the new one as a spare. I intend to keep this vehicle for as long as I can, so I don't mind collecting spares.
Roverlord, and some others as well, let me take this opportunity to thank you publicly for all the great support you have provided me over the last couple of months. You certainly make owning and maintaining a land rover a pleasant experience.
On another note, I think this is my 999th post.
Cheers,
biggin

Originally Posted by biggin

On another note, I think this is my 999th post.
Cheers,
biggin

Your wrong mate it was your 1000th

Just completed a 1200km round trip on the weekend, and the fuel consumption was horrendous even for a V8. Early on I noticed that the new O2 sensor was not responding; it had been working for the few kilometres I had travelled before the big trip.
Other than that, you wouldn't know anything was wrong.
So back to the drawing board. Later this avro I intend to pull both sensors and compare them for colour and contamination. I expect the new sensor will be covered in black carbon as was the old one before I changed it. Also, I'll pull a couple of spark plugs from both sides and check their condition.
Back to the O2 sensors, I expect that the carbon deposit is contaminating the sensor so I'll give both faulty ones a petrol bath and see what happens. Hopefully, they'll both be alright.
I still have a new spare, but I don't want to install it in case it ends up like the other two.
I'll try to post a few pictures tomorrow.

Originally Posted by biggin

Just completed a 1200km round trip on the weekend, and the fuel consumption was horrendous even for a V8. Early on I noticed that the new O2 sensor was not responding; it had been working for the few kilometres I had travelled before the big trip.
Other than that, you wouldn't know anything was wrong.
So back to the drawing board. Later this avro I intend to pull both sensors and compare them for colour and contamination. I expect the new sensor will be covered in black carbon as was the old one before I changed it. Also, I'll pull a couple of spark plugs from both sides and check their condition.
Back to the O2 sensors, I expect that the carbon deposit is contaminating the sensor so I'll give both faulty ones a petrol bath and see what happens. Hopefully, they'll both be alright.
I still have a new spare, but I don't want to install it in case it ends up like the other two.
I'll try to post a few pictures tomorrow.

Temp sensor? might be sending signal saying too cold and enriching the fueling? Careful on Aftermarket like intermotor etc sensors I have found to be hit and miss, best go genuine. Sensor is also vin dependant
MAF faulty and enriching the fueling?
Leaking injectors, over fueling?
Air leak somewhere?

Just a thought did you do an adaptive reset after replacing the O2 sensors, to restore the default values so the ECU can relearn? If might still be in the OLD values compensating for your old faulty O2 sensors, just a thought.

Thanks Mario, a couple of those thoughts did cross my mind, especially adaptive reset which I didn't do.
Wife's birthday today so couldn't get away to the shed tonight. Will give it all a go tomorrow.
Good news was no 3 amigos for the whole trip.

My experience with Motronic in an E36 M3 is that the ECU will learn the new outputs more or less immediately.
There should be an error in the ECU log , but the car should react to the new O2 sensors straight away.

You obviously have another problem as detailed above. I think the first place to look is the temperature sensor.
The ECU uses the o2 sensors for closed loop control as soon as the engine is warm, so I would not be looking at MAF or TPS for example.

Regards Philip A