The Inlet Air Temperature first thing in the morning with just the Ignition on and the Engine cold should be the same as the ambient temperature. I wouldn't worry about it.

Fuel consumption does go down as the weather get colder in winter. 37 for a Diesel is not very good, my petrol car is better than that.

The MAF is just a little bit higher than I would have expected, but I don't know the normal value for that engine.

I'm not sure what should be checked next other than as @KenM has advised.

On 12/3/2022 at 4:12 PM, Tizer said:

The Inlet Air Temperature first thing in the morning with just the Ignition on and the Engine cold should be the same as the ambient temperature. I wouldn't worry about it.

Fuel consumption does go down as the weather get colder in winter. 37 for a Diesel is not very good, my petrol car is better than that.

The MAF is just a little bit higher than I would have expected, but I don't know the normal value for that engine.

I'm not sure what should be checked next other than as @KenM has advised.

My MAP is peaking at 239kph. I also checked out few other things. Cylinder balance at around 2k revs numbers were looking same on all 4. But on the graph noticed odd blip on cyl 2. I also ran glow plugs, they seem to be switching on and off, but I don't know if that's just telling me power is going to them. Or if there working or not. I also get a DTC at around 4k revs. Had it a while but it's never bothered me as I don't blast around at 4k. 

P010f   I replaced MAF at the time as it was lumpy and came on before 4k revs. it got better. But still get it at over 4k stretching out before gear change. But my MPG was around 40 around this time.

I will upload the screen shots off the laptop when home from work. Hopefully this will help shed some light.

I get what your saying about weather temp. But it's not dropped this much, this fast before.

On 12/3/2022 at 4:12 PM, Tizer said:

The Inlet Air Temperature first thing in the morning with just the Ignition on and the Engine cold should be the same as the ambient temperature. I wouldn't worry about it.

Fuel consumption does go down as the weather get colder in winter. 37 for a Diesel is not very good, my petrol car is better than that.

The MAF is just a little bit higher than I would have expected, but I don't know the normal value for that engine.

I'm not sure what should be checked next other than as @KenM has advised.

 

8 hours ago, Simmo80 said:

 

Well it looks like you’re getting boost ok, would have been good to have seen RPM on the graph. The fault code you now have gives you something to look at, check maf is clean, the wiring to the maf. I think you said you had replaced the maf in an earlier post was this a good quality one or a cheapo. Did you clean the intercooler? If so what condition was it in, any corrosion holes anywhere. Have you blanked the EGR? Did you check IAT whilst the engine was cold against outside air temp?

As above, and I would also check the readings from all the Temperature Sensors when cold to see that they all read ambient.

I presume you have the original Air Intake and Filter fitted in the car and are taking the Intake Air from where it should be.

I think it’s a combined maf/iat sensor.