2004 audi a4 tdi not ticking over properly for first 15 seconds when cold , rev counter needle unsteady ?

Water Thermometer by cooling system is called Engine Coolant Temperature (ECT) sensor, and is placed in the right back side of the cylinder head on 2004 Audi A4 1.9 TDI. See picture below:




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A lot of white smoke and engine dying could be bad head gasket. Search 'symptoms of head gasket failure' to make sure before you run it again. Good luck

i think a new one is the order of the day here ,

replace the clutch switch

i have audi a4 tdi 1,9 engine esp blocking back tyer in cold weather ,, do i have to worm the engine

heater core clogged or heater valve

The fuel temperature sender for Audi A4 1.9 TDI is placed on the fuel line near fuel filter (see picture below):



Position 15 (red arrow) - fuel temperature sender

Audi, European design, parts may be hard to find for this, I suspect the automatic choke assembly is faulty, hence giving you the wrong combination of air and fuel mixture causing the smoke. You could however, if you are willing, to remove the assembly and try lubricating and cleaning it, as it may have carbon build up blocking the channels inside. Hope it works, Good luck

Fuel filter or vacuum leak good place to start. Good luck and have a good day.