[Vwdiesel] TDI Starting Poor

[Val Christian]

It's finally getting warmer, and my TDI is starting poorer.

Symptoms:  Coolant temp between 5 and 15C, and engine may take 20 seconds
of crank to get going.  Coolant temp below -8C, and engine starts with a
tap of the starter.
 
Coolant temps are using VAG-COM, and correspond to the outside air 
temperture (OAT).

When engine is warm, or OAT above 20C, start is after a rotation or two
of the engine.

Theory: A short glow isn't happening at initial start in these temps.

Assumption: Sensor indicated by VAG-COM drives glow time.  In this temp
band, there is 0.0 preglow indicated by VAG-COM

Questions:

1. Can the user tweak the preglow cooeficients using VAG-COM?

2. Other problems or issues I should be chasing?

Val