Black smoke & irregular engine idle

[eddie2103]

After a number of times jumping into my wifes Toledo 1.9TDI I noticed the extreme lack of power & performance. I changed the MAF the other night & wow what a difference. Only problem now is the exhaust bellows a plume of black smoke on initial startup and at each change of gear. We have a number of black sooty/oily deposits on the drive. Also the engine seems to pulse when idling and if travelling along in slow moving traffic .

Would appreciate some advice or any ideas.

 

[silver surfer]

Black smoke & irregular engine

could need fault codes clearing or just a good blast down motorway to clear things out

 

[GrayT]

I agree, could be fault codes - idle actuator etc.

Does it fire up OK? One clue when it starts is that the rev needle should give a little blip upwards on ignition, then settles. If it doesn't then it could well be the throttle valve actuator. You really need to get it to someone with diagnostics and hopefully it would be a simple case of resetting the codes (unless that is the motorway blast does the job!)

 

[Muttley]

GrayT wrote

. . . it could well be the throttle valve actuator

Unlikely on a TDI - no throttle

eddie2103 wrote

Only problem now is the exhaust bellows a plume of black smoke on initial startup and at each change of gear.

It could be that the ecu needs to be reset, to clear out the adjustments it learned when the MAF was faulty. The usual advice is to disconnect the battery for 30 minutes. You will need to have the radio anti-theft code handy to get control of your stereo back.

 

[GrayT]

Unlikely on a TDI - no throttle

Oh well. Teach a petrol boy to get involved in a diesel issue. ...idle governor?...deposits in the injectors?

 

[eddie2103]

Fires up without any problem. gave it a fair old blast (50 mile trip) which didnt help at all. Smoke appears on ignitionand at the change of each low gear. Once opened up there is nothing and she seems to run smoothly. Whilst in slow moving traffic she pulses and almost kangaroo's. Managed to contact an AA man with a van who can run the diagnostics (hope he can re set it), but he cant get to us for a couple of days. Will keep you posted

 

[thesonny]

the "smoke" is just carbon build up in the exhaust common on diesels which are running a bit dirty. have you had it regularly serviced by the dealership? a good old fashioned re-tune by the dealership to get the car used to the new MAF sensor as the computer will have been compensating for it being faulty. also black smoke can be caused by piston ring damage i.e oil getting in the ignition mixture. Loss of power can also be caused by cracked cylinder heads, with could also explain the smoke as oil can get in this way.

 

[eddie2103]

The power is now there, in fact its almost like a new car when running on the motorway. Its just low gaer change & driving. Car is going to my local mechanic (also a toledo owner). He is mates with an AA roadside engineer who can find the fault. will keep you posted

 

[shimsham]

i had an Audi 80 1.9 tdi and this happened to me and sorry to say, it was the piston rings an that was the end of it. Good luck