CRD Technical questions about my new KJ

[Actarus-Euphor]

Hi Guys, I'm new here so maybe this post is not at the right place, just tel me then.

On my KJ 2006, 2.8CRD Autom.gearbox, 160000Km.

1)My Diesel Consumption is far too hight (14 litters/100km)

My hypotheses are:

a) I have the engine thermostat out of order,( it doesn't heat, and the indicator on ddashboard stays low)
Could it affect the Diesel consumption because the engine is always running cold?

b) I red somwhere that cleaning the MAF ssnsor could also affect the diesel consumption.
Is it right?

2) When I' turn off the headlight with key already off, theheadlight stays on.
When I' turn off the headlight with engine on, it's OK

any clues for me?

 

[KJowner]

High fuel consumption could be dragging brakes, worn injectors and start-stop driving too, I don't think the torque converter locks up until you are doing 40 MPH.
I put an Essan 88°C thermostat in mine, don't forget to use HOAT coolant, it's a wet liner engine.
MAF is only used to check the EGR function on these old beasts, fueling is controlled by the MAP sensor in the inlet manifold, it's often covered in soot and oil so worth pulling out and cleaning with carburettor cleaner or brake and clutch cleaner, don't poke it it's fragile.
Mine will do between 25 and 30 UK MPG depending on traffic.

 

[Actarus-Euphor]

High fuel consumption could be dragging brakes, worn injectors and start-stop driving too, I don't think the torque converter locks up until you are doing 40 MPH.
I put an Essan 88°C thermostat in mine, don't forget to use HOAT coolant, it's a wet liner engine.
MAF is only used to check the EGR function on these old beasts, fueling is controlled by the MAP sensor in the inlet manifold, it's often covered in soot and oil so worth pulling out and cleaning with carburettor cleaner or brake and clutch cleaner, don't poke it it's fragile.
Mine will do between 25 and 30 UK MPG depending on traffic.

Ok thank you very much for your answer.
My torque converter lock at about 80 km/h 50MPM
I feel like the 1st, 2nd gears are OK
then, I have the impression that 3rd and 4th gears “slip”, then around 50MPH, the torque converter locks up, and then it doesn't slip any more.
- Is it abnormal?
So my next steps will be:
1) clean the MAP sensor (it's free of charge, lol)
2) fit a 88C° thermostat (with the right coolant)
3) bring it to a nautomatic trans expert to do a major service on the gearbox.
-Do you think it sounds good to reduce the Diesel consumtion and to make the motor working in better conditions?