black smoke

[omair]

hi. ive got an audi a4 1.9 tdi which is smoking quite alot everytime i accelerate. the EGR is disconnected but im still gettin alot of smoke coming from the exhaust under hard and medium acceleration. There is no decrease in power or fuel economy. Is there anything else i can do to stop it smoking?? ive checked for fault codes on VAG com and its all clear. can ne one help??
:confused:

[vw754]

What year is the car bro?

[omair]

its a 2004. its not done much milage either, only 27000

[adamss24]

Its normal for a diesel engined car to smoke black under hard acceleration. Its just unburnt fuel. Worry if the smoke is blue or white. Blue smoke means that is burning oil, white means that is burning coolant= blown head gasket all tests with the engine at normal operating temperature.

[nickynibbles]

Excessive black smoke will be an inefficiency in the fuel burning, either down to worn glow plugs or some other form of carbon build up. Change the plugs, if not improvement then consider a remap as this will improve the fuel burning efficiency and has the added bonus of giving you more power & torque!

[vw754]

reconnect the egr! replace or get checked the maf sensor and the common problem causer the 'coolant sensor',make sure your filters are clean,personall id change fuel filter and check condition of air filter,then get the above things checked via diagnostic,or drive down to stoke and get them checked,25 quid.

[omair]

ive checked on VAG com for faults but everything is clear. if the maf sensor or collant sensor needed changing, would it come up as a fault on VAG com? ive checked the air filter, it doesnt need replacing yet. il get the fuel filter changed and see if it helps.

[vw754]

coolant sensor wont show a fault until it stops working altogether,you need to check the reading, you need to see what temp coolant sensor is displaying on vag-com when the car is at normal tempreature. your coolant tempreature should read anything over 80 c, anything under that means its still running on choke.

You can disconnect the maf,if car runs with less power,you know the maf's working,just clear the code with vag-com once you reconnect the maf.

[omair]

ive changed the fuel filter but no difference. still alot of black smoke coming out everytime i accelerate. what are the causes of unburnt fuel?

[godfried]

Try an injector cleaner fuel additive. Pity that you just changed the fuel filter. Otherwise you could have filled it up with the additive and poured the remainder in the fuel tank. Does wonders mostly!

[Marco34]

I'm with godfried! Try and good additive like Forte diesel treatment. Excellent stuff. I'm advised by a specialist to add the whole bottle to an almost empty tank then put about £10 on top. Not a full tank. Specialist would even disconnet the fuel filter and run the treatment through neat. In the case of yours that would have been good to fill the filter with it. If Air filter and maf are clean I would clean the EGR and re-connect.

If you've just bought the car it could be that it's got sooted up with short trips etc. When hot give it a good blast with some fue additive, ie Forte! Well worth it. Mine does short trips daily and has covered only 34k on a 2001! Not a bit of smoke. every 12 months filters are changed and oil every 5k 6 months. It keeps it sweet ;)

[omair]

only if i knew this earlier lol. ive just added sum diesel treatment to a full tank.. what is the MAF and wer is it lol i dont think it could be the EGR because i had it disconnected for abit and the car was still smoking alot..i dont understand what it could be because fuel economy is good, the drive is smooth and there is no loss in power.

[omair]

i think i may have found the problem regarding the black smoke. i disconnected the MAF and took the car for a spin. i told my m8 do drive behind me to see if ne smoke comes out. he told me there was no smoke at all. then i connected the MAF and told my m8 to drive behind me again. this time there was loads of smoke coming out. when i had the MAF disconnected the car lost all of its power. so does this mean i need to change the sensor?

[nickynibbles]

Thats a good probability! Certainly its what i'd do next.

[omair]

problem sorted :D there was a split in the intercooler hose which was causing it to smoke. ive had the hose replaced, cant see any smoke and the drive of the car has improved. thanx for the advise everyone;)