audi a4 2.0tdi rough running & excess white some when cold

[lee1970]

Hi all,
we have an audi a4 ,when started from cold runs very lumpy (slight misfire) & has excess white smoke,when on road test at about 2000rpm very jumpy.no fauts codes.
checked compressions all good,
re flashed ecu
ok heres what i have replaced

fitted 4 new injectors from tps & loom in head & glow plugs
new inlet manifold
new cylinder head
new egr valve
throttle valve as old one full of oil
checked turbo shaft for play looks ok
checked egr cooler & smoked tested then smoked tested all system
drain fuel tank changed fuel filter checked intank pump
changed fuel pump on back of cylinder

checked timming all good there

car runs better when hot with no smoke on tick over
any help would be great
thanks lee

[a8 tech]

Check the measured value blocks 18 (all values 0) and 23 (values: -80 µs in the idle speed, -100 µs at 1500 rpm). If the value is over 100, this may be a sign of air in the fuel system.

Fit a clear fuel pipe and check for air on start up. Also check coolant and fuel temp reading before starting

make sure you have .50 bar before the tandem pump residual pressure and check the egr cooler change over is working on the cooler pipe

make sure the valve timing in measured value block 4 zone 4 is around 2.5 as well

also the egr wiring loom can take on oil back to the ecu and cause similar issues, disconnect the egr plug and look inside the pins for oil.

blank off the egr pipe as well to rule out leaking egr gas putting dirty air in as egr is active upto 2000 rpm so kind of matches your symptoms

[lee1970]

thanks for your reply a8 tech, with regards to checking egr cooler when would should the change over take place,
lee