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?

 

[KJowner]

This should certainly help with the fuel consumption. Another thing to check is the EGR valve, make sure its not stuck open.
The auto box sounds odd, I haven't noticed mine do that, it kicks down if I floor it but there is no obvious slip. Is your fluid level OK and clean?

 

[Actarus-Euphor]

I'll check the oil level and quality, but for sure I'll bring it to a Auto box expert.
I discovered this evening a new klong noise in the rear axle...... By switching Bw/Fw.
I really need to take care of this car and to make it reliable

 

[seafish]

I really need to take care of this car and to make it reliable

No Problem — Just Empty Every Pocket

 

[KJowner]

I'll check the oil level and quality, but for sure I'll bring it to a Auto box expert.
I discovered this evening a new klong noise in the rear axle...... By switching Bw/Fw.
I really need to take care of this car and to make it reliable

Clonk on forward/reverse and acceleration/ braking is usually the rear upper wishbone, also known as the boomerang.

 

[Actarus-Euphor]

Clonk on forward/reverse and acceleration/ braking is usually the rear upper wishbone, also known as the boomerang.

Thank you very much, I'll check it right now

 

[Actarus-Euphor]

Thank you very much, I'll check it right now

So to bring an update, the "klong" is comming from the transfert case silentblocs....., one is dead, I'll order it asap.

 

[Gipsfuss]

There is a viscous heater, that is operating when the engine is cold. It causes load and will increase the consumption, when its always on.

 

[WWDiesel]

If the thermostat has failed causing the engine to run too cold all the time, it will greatly increase fuel consumption.
The gauge should run slightly below the 12:00 mark. See picture below.
If the EGR valve is sticking partly open, you could be losing boost pressure which will greatly affect fuel usage.
If the FCV (flow control valve) has failed, it could be partly stuck closed and limiting air flow and boost pressure into the intake manifold.
Best to disable the EGR and block the feed tube off and remove the butterfly plate out of the FCV.
If the MAP sensor is all gummed up from the EGR crap, it should be replaced or at least cleaned as it controls fuel injection amounts via the ECM.

 

[KJowner]

I forget you all have FCV's, my Jeep is old enough to have missed that out.

 

[Actarus-Euphor]

If the thermostat has failed causing the engine to run too cold all the time, it will greatly increase fuel consumption.
The gauge should run slightly below the 12:00 mark. See picture below.
If the EGR valve is sticking partly open, you could be losing boost pressure which will greatly affect fuel usage.
If the FCV (flow control valve) has failed, it could be partly stuck closed and limiting air flow and boost pressure into the intake manifold.
Best to disable the EGR and block the feed tube off and remove the butterfly plate out of the FCV.
If the MAP sensor is all gummed up from the EGR crap, it should be replaced or at least cleaned as it controls fuel injection amounts via the ECM.

Thank you for these really helpful information.
BTW, what is FCV?

 

[WWDiesel]

Thank you for these really helpful information.
BTW, what is FCV?

Flow Control Valve. It creates a low pressure zone to allow exhaust gas to be sucked into the intake for the EGR system.
All the EGR parts are a crap addon to satisfy emission requirements and are notorious for failing and causing problems.
Most owners get rid of them and get a tune (reflash) for the ECM by Marco aka Yeti to get rid of all the DTCs caused by removing all the EGR parts.

 

[Actarus-Euphor]

OK, thank you very much, I understand better now.