hello , i have had the mazda 6 2.0 diesel for 6 months was fine until it started to blow out black smoke every time its revved a little hard and is getting worse,

fuel cleaner done
oil change done
fuel filter done
oil filter done

starts smoking at 3,000 revs like its burning oil so is this injectors,turbo or something worse

117000 on clock,serviced regularly doesnt seem to be much power loss either just leaves large puffs of black smoke at the back at idle or when on long drive , go faster>smoke>go even faster = more smoke!

any help appreciated, thank you

 

Black is an indication of unburnt fuel, you have either: Injection issues, timing issues, aspiration issues (turbo, manifold, intercooler etc), exhaust issues or transmission (if automatic) issues. There are lots of potential problems here and almost none are cheap (you already covered the cheap ones), so let the games begin!! First off add your car to your sig (use mine as an example) so we know your year,model,engine,trans e.t.c..... Now lets see...... How does the car start, does it start normal or does it have issues? Can you hear the turbo spooling up at all, if you cant hear it can you feel the boost come on? How much power loss are we talking? Whats your MPG(mention if UK or US gallons) or L/100km? Is there difficulty with hot starts (hard to start after engine hot)? Was this a sudden development or gradual? Is the intercooler (radiator looking thing in front of or below radiator) damaged? All turbo hoses attached and in one piece? Wastegate stuck? Any fuel system service done besides the fuel filter? Is it 117,000 miles or kilometers?

More questions to come after some answers

 

wow, what a writeup

yes you are right forgot to mention(sorry) the intercooler leaks oil all the time

oil that should not be there i think

mpg is ok (uk) averages 35-40mpg

manual gearbox

powerloss is not an issue

hot startups ok no problem

boosts fine can hear it spool up ,but it sounds as if its working harder than before? hoses seem ok cant see any loose , and wastegate dont know where that is to check?

thanks very much,sorry about the other thread hijacked.

 

Ok the intercooler should NOT be leaking anything especially oil, there should only be air going through the insides, if there is oil its coming from your turbo through a bad seal. If you dont know an intercooler cools the air charge from the turbo which is hot from being compressed, it flows through the cooler (like water does in the radiator) and is cooled by air outside flowing through the fins, if there is an air leak you have a boost issue where you are not getting enough air to burn all the fuel (hence the black smoke). If you meant the oil cooler is leaking then that is a different issue but one that should be fixed. The wastegate is what prevents your turbo from overboosting the engine, it lets exhaust gases bypass the turbine so there is less power to spin the turbo thereby less boost, if its stuck open then your turbo never gets up to speed and boost is low/non-existent, if you are hearing the turbo then the wastegate is not a big issue right now. Can you take pictures of the intercooler leak? Are all the intake hoses soft and squishy (oil softens the hoses, makes them prone to blowing off as well)?

 

ok that makes sense i have a small puddle of oil 8 out 10 time when the car is parked up right below the intercooler so its probably a bust seal

yes you are right the pipes are oily and soft because i cleaned out the intercooler a month ago after i thought it was just a build up of crap
but the problem came back

would you recommend a new turbo or turbo seal kit or something

i have been trying to find a repair kit as i thought it was a possibilty..

thanks

 

To check the turbo you can remove the pressure side hose, when its removed reach in and see if you can wiggle the turbine at all like this although I am not sure I would call the first one acceptable....... If it looks like the blades have been hitting the wall you will need a new turbo, either way its looking more and more like a new/rebuilt turbo will be needed.

 

ok i know what i am doing with my day off, ok just one more thing where does the pcv valve come into all this it has been mentioned in most threads , is it worth checking? thanks for your help

 

Diesels dont have PCV (Positive Crankcase Ventilation) valves, they use something called a CDR (Crankcase Depression Regulator)valve but it is the same thing in principal, takes crankcase gasses and burns them with the air charge, I am not sure where the Mazda diesel CDR is to be honest but what I do know is the EGR valve on them can get plugged rather badly and need to be cleaned every now and then. Also dont forget the year of your car in your sig

 

oops no pcv! cos i cleaned my egr last month shows you how much i know

thanks so much no doubt i will be back soon, chao for now

 

Mazda Tirol is right about intercooler leaks, especially with your confirmation of it.
Car runs richer if you have intercooler air leaks.

"I target 11.6. Was seeing 11.3, 11.2. Thought it was my MAF calibration in the WOT region, but it turns out the OTS calibration in that region is pretty close if not spot on. Tried adjusting the MAF anyway, but the correction factors introduced bumps in the MAF curve (first sign). Did a run with spring pressure (< 12 PSI max): AFRs were closer to target. Fixed all leaks, my AFRs are now much closer to target."
"I would do a leak test regardless of an FMIC. I did one and assumed I wouldn't have any. My car was pulling just fine. Finally made a tester and what do you know... A boost leak."
"if you have an FMIC, your chances of having leaks are much higher, since there are many welds and connections."
ABOVE FROM: If you have an FMIC kit, check it for leaks! - Mazda 6 Forums : Mazda 6 Forum / Mazda Atenza Forum
That thread is for a Turbo MazdaSpeed 6 Gas with a front intercooler (not diesel). However the same principles apply. His kit was fairly new. Yours could be worse. FMIC = Front Mounted Inter Cooler