Sluggish when cold start up A4 2.0TDI - TT plz help

[gio6500]

Hi

I think one for TT me thinks but all advice is appreciated.
Car first thing in the morning after left overnight is a bit sluggish in starting up. Usually I turn the key 3-4 times before I fully start the engine so that I can prolong the life of the glow plugs.

Another thing to point out is when revved exhaust gives out black smoke but not when revved. Normal or linked to glow plugs?

Cheers

[TDIfurby]

How is your battery at the moment?

Not sure what you mean about the black smoke as they can all give off some. The best thing to do would be to find someone with vagcom who can read the ECU for any faults. It is often a flaky sensor which can cause excessive black smoke.

[gio6500]

Battery seems fine. How can I check? The battery light comes on perfectly at beginning etc and then goes off once started.

I've connected to vagcom and one of the injectors was a bit weak.

Could this be it?

[Tame Technician]

Need more input really.

Does turning the key 3 or 4 times to prolong the glow plug burn actually make any difference?

Glow plugs dont do much in this weather and even in the winter the car will start fine with them disconnected. They are only there for emmisions.

Try clamping the fuel return line (artificaially raises the fuel pressure) and see if it starts sooner. If so I'd guess injector seals.


As for the black smoke, I asuming you mean once its up and running not at start up?

Boost leak or EGR valve failures are the causes of black smoke.

[TDIfurby]

Injector failures are quite rare, especially on the newer 2.0 TDI engines, so I would hope to rule that one out on the grounds of "what are the odds?"

Have you tried going out on a cold start and logging the requested VS actual boost to see if you have a slight turbo issue. Going out and logging group 11 (I think this is it, should have specified and actual boost readout) and drive along seeing if there any discrepancies between the two. PS: Take a passenger as driving and checking two readouts on a laptop is not advisable

[gio6500]

TT - i have an appointment soon to link to onboard comp to see what the actual problem is.

Another thing - my car was running on low fuel yesterday around 15-20 mile mark and thought I'd fill up. I filled up around £7 and came back to the car to see if it increases my mileage capacity which it did not. I thought this may take time on the audis so thought I'd leave it overnight. Woke up this morning and it was still showing me the same mile range. Anyone know about this problem?

Cheers