Hi. I have a 1991 hymer fiat based 2.5td motorhome and it's kicking out black smoke when starting and if you rev the engine, but no smoke at all on tick over. It has done 91,000 miles, sounds and pulls well so not sure if it's piston ring wear or something else? Any ideas?? Thanks. Darren

Black smoke is soot. Common when accelerating as extra fuel is injected. More common on engines more than a few years old, newer ones are generally better, not due to lower age, but better controlled fuelling. Black smoke is the result of less efficient combustion.

Blue smoke is oil, which would show poor engine condition, or leaking turbo seals.

White(light grey) smoke is unburnt fuel. Sometimes present at startup on cold days. Other times indicates poor combustion, or excess fuel, more than the air can burn.

If your black smoke is only on acceleration, get a good quality injector cleaner, like Forte or Wynns and dose it. Cleaner injectors may well cure it. Otherwise, if it goes ok, sounds ok and fuel consumption is ok, don't fret.

Thanks. That makes sense as the smoke does smell strong of diesel. I will try the injector cleaner and see how it goes.

hi Darn66, i own a 1996 1.9td and had same problem. i add two stroke oil to my diesel at a ratio of 1 to 200. stopped the black smoke. apparently the theory is that the 2so helps with combustion and also lubricates the cylinders. i used injector cleaner for ages until i discovered this solution.

Now tried these things..
I have changed fuel filter, oil filter, oil. I tried the injector cleaner directly into the fuel filter to clean the injectors which made minimal difference.

So I decided to take out injectors to send off and get tested. The results were that 2 didn't work and the other 2 were weak so I had them re-tipped and calibrated by a diesel specialist.. They are now installed and make a big difference to performance as you can imagine but the Black smoke is still there on acceleration & not on tick over?
It is less than before but still smells strong of diesel... Am I being fussy? as the engine is a 1991 2.5td with 98k & no dpf filter and is this to be expected??

Any advise will be greatly received.
Darren

hi Darn66, have you tried two stroke yet? it makes quite a difference in engine noise so i think it helps with cylinder lubrication. apparently modern diesel contains a lot less sulphur than it did when our vans were new and the 2so replaces it. a bit like lead in petrol, i suppose, but i'm no expert.

Two stroke oil (mineral) has been added to my 2.8 for the last year at a percentage of around 200:1
or 1/2 litre to a full tank

I'd be looking for a boost leak check hoses, jubilee clips, check intercooler for damage, check/replace hose to the LDA on the injector pump. LDA diaphragm itself may be the issue.

If you've had smoke since you got the van the previous owner may have done some diy tuning and turned up the mail fuel screw or smoke screw. Main fuel should be obvious as it should have tamper paint on it.

Thank so much for all your comments. I will have a tinker this weekend and see if I can find a Haynes manual for the van..

I haven't tried the 2 stroke oil mix yet as I wanted to try and eliminate the cause first, if I can get to the bottom of it!!
Thanks again

Just wondering if you solved the smoke problem yet.
Just joined so only now seen this post. Have exactly the same problem with my 1996 1.9TD.
Mors noticeable under load, like going up a hill.
Would like to solve it.

Hi Wayne.
Not had a chance to look over the engine for split hoses etc.. I have taken it out for some long journeys and pushed her through the gears to try and clear her out a bit. A mechanic friend of mine did say that I might be to fussy/expecting perfection? It's is 23 years old and comparing it to modern cars & vans with DPF filters and catalytic converters it is to be expected.

Darn66 said:

Hi Wayne.
Not had a chance to look over the engine for split hoses etc.. I have taken it out for some long journeys and pushed her through the gears to try and clear her out a bit. A mechanic friend of mine did say that I might be to fussy/expecting perfection? It's is 23 years old and comparing it to modern cars & vans with DPF filters and catalytic converters it is to be expected.

Click to expand...

Catalytic converter doesn't do anything for smoke, and a dpf would be blocked in no time with it 'kicking out smoke' - they get blocked as it is with modern hcomputer controlled high pressure injected engines running perfectly.

Black smoke is normal if you blip the throttle as the injected quantity increases faster than the turbo can spool up. Lots of black smoke is not normal under normal conditions. Could be not enough air, e.g. air filter blocked, hose collapsed/split, turbo wastegate stuck open, loose, damaged, turbo core damaged, exhaust blocked. Too much fuel, poor atomisation of fuel, timing retarded, poor compression. e.g. injectors / pump / pump timing, stretched timing belt, piston rings, valves, valve seats, valve stem seals etc.

Blimey.. Well I've had the injectors re-tipped and tested by a diesel specialist and that made a slight difference. I didn't really want to strip down the engine just yet. I am currently building a new garage so once it's all done I can get her in over winter and start checking the points you've made.. Thanks for the advise it's much appreciated.

Darn66 said:

Blimey.. Well I've had the injectors re-tipped and tested by a diesel specialist and that made a slight difference. I didn't really want to strip down the engine just yet. I am currently building a new garage so once it's all done I can get her in over winter and start checking the points you've made.. Thanks for the advise it's much appreciated.

Click to expand...

A boost gauge on eBay for a few quid will quickly narrow things down

Darn66 said:

Blimey.. Well I've had the injectors re-tipped and tested by a diesel specialist and that made a slight difference. I didn't really want to strip down the engine just yet. I am currently building a new garage so once it's all done I can get her in over winter and start checking the points you've made.. Thanks for the advise it's much appreciated.

Click to expand...

could be the erg valve has faulted then black smoke will blow out under load

Hi. I have recently taken the ducato to a diesel mechanic to try and source the problem with the over fuelling smell coming from the exhaust.
He had an idea that the fuel pump could be out of timing? So he's checked the timing and everything is spot on. He found a split fuel hose that he change. The engine is a mechanical turbo diesel so very basic with no egr valves etc..
He advised maybe the next thing to do would be to send the pump off to be checked /reconditioned if required.
Wanted to get some more input from anybody that is used to this type of engine? It's had full engine service. Injectors have been re-tipped and tested. All hoses have been checked. Now timing and fuel pump timing is all correct.. What's next!!

I had the same problem it poured smoke out by the gallons.I got home and tinkered under the bonnet and found a hose had come of.It was very hard to find as the hose appeared to be on ok. Put it on correctly and it fixed the problem.