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1.8tdci smoking


Gray J
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My 1.8tdci kicks out black smoke when accelerating at 2.5-3k revs, I understand it's a diesel, I don't do long distances/motorway driving in it, anything to worry about?

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Diesel engine problems

Black Smoke - this is the most common one and is really just an imbalance in the air to fuel ratio - too much fuel to not enough air. This means either too much fuel is being added to the mix or there's not enough oxygen being supplied to burn the fuel. The black smoke is full of particulates that are basically large diesel particles that normally would be burned as fuel. Any way you look at it, a diesel emitting black smoke is not going to be getting the optimal fuel mileage it should be getting.

Most common causes of black smoke are faulty injectors, a faulty injector pump, a bad air filter (causing not enough oxygen to be supplied), a bad EGR valve (causing the valves to clog) or even a bad turbocharger. Some of these are easy fixes.

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I'd check your air filter is clean as a cheap/easy starting point.

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2 hours ago, Gray J said:

My 1.8tdci kicks out black smoke when accelerating at 2.5-3k revs

It is likely to fail its next MoT, too. They test smoke.

I can add to Russ's list (above): MAF (Airflow sensor), MAP (intake pressure sensor), possibly Cyl. Head Temp. sensor & air intake Temp sensor.

Basically anything that can confuse the pcm, into putting too much fuel in.

With that list, I think the only 2 ways are: take it to a specialist with diagnostic equipment, or get your own diagnostic system (and you can get a really good one for £15!), and learn how to use it to test sensors, injector offsets, and the like.

You could try just blanking the EGR, to verify if that is sticking open (few £ for a Stainless Steel plate off Ebay), but most of the other possibilities will need diagnostic testing. You can't just replace injectors for a quick test!

For more about diagnostics, see:

 

 

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check the obvious, make sure all hoses from the turbo to the IC and back up to the manifold are attached and not split, remove them if possible and inspect, a small split without any loading on it turns in to a big hole when you shove 35PSI against it, or in other words, the pipe swells.

then check the air filter and clean / replace, pull off the MAF sensor, usually next to the airbox, clean it with some electrical contact cleaner, do the same to the MAP sensor, usually found after the IC, drop the IC and clean it out, see how much oil is inside it.  All of that will cost you the square root of bugger all.  gets a little more interesting after that but its worth checking the simple stuff first.

 

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I've had new injectors done 6months ago & it's booked in for a terraclean next wk so see how that goes & take it from there, thanks for the info!

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1 hour ago, Gray J said:

I've had new injectors done 6months ago

Quick question: Was the pcm properly re-coded for the new injectors?

Any good garage or specialist should have done this automatically, but it is worth checking. If the injector calibrations in the pcm are not correct, that could cause overfuelling.

(f you have had an MoT in the intervening 6 months, with a smoke test pass, then it can be assumed this was done ok.)

If the injectors were done properly & re-coded, then that makes injector problems less likely, unless some dirt got into them, etc.

Forscan can re-code, and possibly check the existing coding, of injectors.

 

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Stick some forte  diesel system cleaner in and take it for a good drive and rev it higher than you would normally through the gears you'll see sum crud come out and it should run smoother and change gear smoother

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It's been through mot fine since injectors were done, was a reputable recommended garage so I assume all was done correctly, have been running it on premium diesel aswell, terraclean booked for Monday so see what that does, will post results.

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35 minutes ago, Gray J said:

mot fine since injectors were done, was a reputable recommended garage

That is good news, hopefully it is not injectors then. They were a bit of a favorite candidate: bad spray pattern, or droplets too large, or leakage into the cylinder, could all give smoke, and not show on any diagnostics.

See what the clean does, and how it goes from there. Darren (Dee_82) also gave some good advice about checking the hoses to the intercooler. Leaks there can lead the pcm into putting too much fuel in, as air is escaping.

But I do think investigating some diagnostic equipment would be a very worthwhile thing, you have nothing to lose, and I am certain it will come in useful at some stage. Cars are only getting more complex, and garage charges keep rising!

Hoping for the best,

Peter.

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  • 4 weeks later...

Update on Focus smoking, had terraclean done & was found I had a leak on injector overflow pipe (think that is the right wording!) That is all repaired, still getting same smoke issues as before, so the story goes... i have previously had injectors done, has been through an mot since & had terraclean done, I'm not mechanically minded by any means so any advice will be appreciated, many thanks.

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I think the important question is, does it always dump a cloud of black smoke, or is it just every now and then?

judging by the fact you passed your MOT I'm guessing its not all the time.  you said yourself that you only do city driving without much motorway stuff? Hows your MPG, does she still pull when on boost?

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Car pulls fine on boost, notice at night when vehicle behind lights are on it kicks out white smoke (don't see it in daylight!) & dumps out black smoke when accelerating hard tho don't go hard very often (I'm old now so long gone are the days of driving hard!).

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On 01/08/2016 at 5:18 PM, Gray J said:

had terraclean done & was found I had a leak on injector overflow pipe ....

....dumps out black smoke when accelerating hard

The MoT test is done with the engine out of gear, just using high revs. So smoke under heavy load may not show up. I don't think it is doing any great harm to the car, so is probably not in vital need of attention.

It is likely to be annoying for drivers behind!, & is a bit embarrassing for you, perhaps. Modern diesels should not do that. Also if it smokes while the EGR is open, that could be helping clog up the egr & inlet manifold with soot. But the egr is normally closed under heavy acceleration, or at high rpm, so this may not be a problem.

Have the intercooler (called IC above) hoses & pipes been checked for leaks? (As Darren (Dee_82) suggested). This is quite easy, just feel around, squeezing the hoses, checking the pipes. In case you are not sure, the intercooler is the small "radiator" right at the front of the car, and the hoses are the big ones, one each side of the engine, linking it to the back of the engine. The air filter box need to be lifted out to see one. Checking the intercooler itself is a bit harder, front bumper probably needs removing.

Then it is down to the various engine sensors, listed above. Forscan (item 4 in my "Kangarooing (!) reference above) can monitor the readings of most of these, that might provide some clue. But if you are not technically minded, it will need a diesel specialist, or good garage, to check them out.

So I advise looking in to the problem at some time, but it does not sound urgent.

Peter.

 

 

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Thanks for the advice... much appreciated. 👍

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