A4 B7 3.0TDI Quattro Smoking on Acceleration

[TurboJeff]

Hi All,

My A4 B7 3.0TDI has a smoking problem, when I accelerate from a standing start or when cruising slow at low revs, as the revs pick up the exhausts kick out a plume of light black smoke, the harder I accelerate the more smoke comes out. It only happens on the initial depression of the accelerator once the revs clime up say after 3000rpm the smoke is not there anymore.

Does anyone have any ideas on what it may be? engine has about 120k on it.

 

[EXSpartan36]

Normally black smoke is caused by excess air in the intake. Check all your boost hoses for splits. Especially between the intake manifold and the intercooler.

 

[desertstorm]

Normally black smoke is caused by excess air in the intake. Check all your boost hoses for splits. Especially between the intake manifold and the intercooler.

Excess air in the intake doesn't cause black smoke, not enough air causes black smoke. You are right to suggest checking the boost hoses and the intake system in general for leaks. Usually you can spot these by looking for wet oily patches, as the crankcase breather fumes are passed through the intake system and any leak allows these to be blown out.
A check for fault codes is a good idea.

 

[RAF_S7]

Over supply of fuel - faulty or worn injectors - can also cause black smoke, as can oil in the combustion chamber.

Better to get a proper diagnosis from a diesel specialist.

 

[adamss24]

Could also be That the DPF was gutted and a **** map/Dpf off was uploaded in the ecu, pretty common now ! There are many outfits out there that use the Ecu safe which turns off a lot of safety measures that factory has built in !

 

[TurboJeff]

The only fault code I have is the swirl flap linkage it worn so is triggering a fault outside of range of movement.

 

[TurboJeff]

I've read some where about the EGR valve getting clogged up/stuck? is it worth cleaning this up?