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Black smoke on acceleration, but not all the time.

mwhtc

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Joined
Sep 7, 2021
Messages
143
I've had my LC a bit longer now and used it more frequently, and have noticed that when I boot it I leave a big plume of black smoke behind me. When I say boot it, I mean when I do above 2,500 rpm. However, I've noticed that it will sometimes do it at lower revs as well, but not all the time either.

The route to work is usually mixed A roads and country lanes. One part of the journey I cross a fairly fast NSL A road, so often I boot the car across the road. I look for smoke, and sometimes I get it, sometimes I don't.

Now the last diesel I had was a God awful Peugeot 3008 which was blessed with a DPF, and the only time I got something similar was when it complained about a DPF blockage and I just revved the balls off of it and sent out black smoke all over the place. So I'm trying to work out if this is a feature of the D4D engine in these LandCruisers, but often when I Google the issue there's equal talk about injectors, EGR valves, and that it's a feature of the car. It can't be all 3!

To that end, I've had the EGR cooler changed when it went in for the air con to be fixed (which isn't fixed) which seemed to stop the black smoke for a time (which makes me think the EGR valve could be dirty), and the injectors they are clattery when the engine starts from cold for about a minute. After which they're fine. I looked this morning when I started it from cold for any smoke, and there is nothing from the car at all. I checked the air filter on Friday and it is brand new. So I don't think the car is struggling to breathe either, which I saw was a suggestion somewhere else when it came to black smoke.

As I said with my usual driving, it's usually A roads and country lanes. I go from 30mph right up to 60mph and down again, and it usually takes me half an hour to get to work and back from it. On my last half tank of diesel I got 21/22mpg from it, and have been using the Milners EcoMax with every fill. I usually fill up at Sainsbury's, but Saturday I went to BP instead, again with the EcoMax stuff. I'm keeping an eye on the smoke to see if it's the quality of diesel as well.

So, really, am I right to be expecting black smoke some of the time when accelerating? Or is this something these engines shouldn't be doing?
 
Most common causes are stuff you have checked, Inc air filter,..... Faulty Injectors/ Pump, EGR valve/ Turbo etc etc.... Fault finding Nightmare mate, Sorry to ask but which 120 is it..... LC3/4/5?
 
Most common causes are stuff you have checked, Inc air filter,..... Faulty Injectors/ Pump, EGR valve/ Turbo etc etc.... Fault finding Nightmare mate, Sorry to ask but which 120 is it..... LC3/4/5?
Sorry should've said that - it's an LC5.
 
Black smoke is unburnt diesel.....
Make sure you don't have a loose intercooler pipe or hose..... , blocked air filter etc .
Black smoke is certainly not a design feature of any modern diesel engine...... you will see something in following cars headlights at night possibly but certainly shouldn't be "rolling coal" as you accelerate away from a junction in daytime .
 
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As Jake says, do a EGR blank/delete.. There is a thread on here somewhere explaining but cant remember who did it... I think the LC5 had a different Turbo to the others, That were sometimes troublesome, But more electrical than mechanical....... Oh! and maybe lay off the Eco Max stuff for a while till you find the problem
 
Have a look for any devices such as a tuning box, possibly plugged in via an adaptor wire to the back of the fuel pump.

120's running well don't give out any smoke at all, should also be rather more rapid in take off and acceleration than the stated power figures might suggest, your fuel figures sound a little heavy, i'd be expecting 25mpg with an auto box on such running.
When accelerating gently in a built up area can you hear the turbo spooling up nicely with the window open, you should be able to.

Worth getting Techstream and reading the injector and fuel figures, or finding someone who can.

I also add Millers and about 200ml of 2T oil to every fill up, not a sign of smoke.
 
Even when my LC5 was 'Wizz', Pop, Bang! Knocking its Tit's off there was never a hint of Smoke....... HOW!!! Il never know!
 
White smoke is unburnt diesel, black smoke is excess diesel. Mine will give a small puff of smoke as its warming up on acceleration but its pretty ok when fully warm. I put this down to the Tunit chip helping things along a bit.
 
Thanks all.

I couldn't find the threads made by TONYC11 on here, but I found them on the other site and read through the whole procedure. Definitely something to consider doing in the next few months.

One thing I did do on Monday was put the wagon in D4 (or 4, D4 I only ever saw on Rovers and Hondas, but you know what I mean) and drove it at higher than normal revs. Rubbish came out the back, but since then it seems to not be producing the smoke like I saw originally. But I should add that it's not rolling coal all the time, just the odd time.

I will check for loose pipes as well, but I definitely think the EGR delete is probably a better way for me to go. I've no idea if there are performance upgrades or anything like that so that, again, will be another thing to look for.

EDIT: One thing about Techstream, I've seen it mentioned but I have an OBD2 to USB device for when I had a Subaru - for the 3 months I had a Subaru I should say - and the photos I see of the techstream stuff seem to have the same cable. So does anyone know where to get the software? Found one website but I'm reluctant to trust some sites as they look proper dodgy!
 
Thought I'd give an update on this.

On my way home from work a few weeks ago, I decided to do an italian tune up. I'm not blessed with big hills between where I work and home, so I stuck the car in to D3 and gave it the beans. Black smoke poured out like mad. Did this for a good 20 minutes.

Since then, not a drop of smoke from the back of the car until recently, where I could see it again. So not rolling coal, but you would just see wisps of black smoke, then a few days later I'd see more. I gave it the beans over the weekend again (so about 3 weeks after the first time). I haven't used EcoMax during this time.

I'm inclined to believe now this is an EGR issue, so I'm going to get the kit and sort it out in the spring - I'll report back!
 
Small update on this.

I had the pushchair in the back of the LC in the run up to the wife giving birth (which happened on the 7th December - both doing well!) and given the recent petrol issue, the wife was concerned that if she went in to labour I'd have no diesel to get us to the hospital. So I went to fill up, and I had the bottle of EcoMax in my hand and looked at the pram being quite close to it. I remember there being a bit of a smell from it from being used, and I decided to both heed Higgy's advice as well as decide not to put it back in the car while the pram lived in the boot. There wasn't much left after I gave it one last glug.

Since then, I did many 30/40mph trips to and from the hospital, as well as one good thrash on the throttle shortly after the fill up. I'd say for a good 5 weeks now I've not seen an ounce of black smoke from the engine.

The only time I saw any black smoke was on Sunday as I went to Quorn to see the Deltic train run, which is a good 90 minute one way drive for me. On the motorway I went to overtake and I put my foot down and I saw a lot of black smoke. But I was doing well over 3,500 rpm at this point. Again though, before and since then, when pulling off the line in the traffic light grand prix and joining traffic, I've had no sign of black smoke.

I'm inclined to believe that this is more of an EGR valve issue, so I'm saving the pennies to purchase the kit as mentioned above. Hopefully around March time, sleep and time dependent given my new son thinks everyone should be up screaming during the night, I'll do the EGR delete then.
 
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