Increased fuel consumption 1.6HDI

[munkey]

Hi All,

I've got a 2011 Berlingo 1.6hdi 90ps (no DPF) with 94k miles of mostly motorway journeys on the clock. I used to get a decent 600-620 miles from brimming the tank until the light comes on without fail. About mid way through 2021 the MPG went down and I'm struggling to get 450 miles per tank which is nicely aligned up with the diesel prices going through the roof  
I know the MPG computer is horridly inaccurate but it used to be 62MPG and now its somewhere around 50MPG 

The journey terrain and how much load is in the van hasn't changed. I've checked tyre pressures regularly are up to spec and replaced the air/fuel/oil filters every 10k miles. Any ideas?

Thanks

[saskak]

Hi All,

I've got a 2011 Berlingo 1.6hdi 90ps (no DPF) with 94k miles of mostly motorway journeys on the clock. I used to get a decent 600-620 miles from brimming the tank until the light comes on without fail. About mid way through 2021 the MPG went down and I'm struggling to get 450 miles per tank which is nicely aligned up with the diesel prices going through the roof  
I know the MPG computer is horridly inaccurate but it used to be 62MPG and now its somewhere around 50MPG 

The journey terrain and how much load is in the van hasn't changed. I've checked tyre pressures regularly are up to spec and replaced the air/fuel/oil filters every 10k miles. Any ideas?

Thanks

I'm sure cancunia will come along to mention the MAF sensor and I suspect that he might be right. Difficult to test the MAF sensor, but likely to be that. Diesel fuel changes in summer/winter times, they add a few additives so the diesel does not freeze, so it somewhat depends on when you started noticing the drop in fuel consumption, but I doubt this will explain the big difference in consumption.

[munkey]

Good shout, if the MAF was defective would it throw a fault code? Just wondering if it's worth getting a generic code reader before splashing out on a new sensor

It started happening summer last year. I had the van fully loaded to the gunnels and did a hard 2000 miles. I expected the economy to go through the floor but it never recovered when I took all the extra weight out

[saskak]

Good shout, if the MAF was defective would it throw a fault code? Just wondering if it's worth getting a generic code reader before splashing out on a new sensor

It started happening summer last year. I had the van fully loaded to the gunnels and did a hard 2000 miles. I expected the economy to go through the floor but it never recovered when I took all the extra weight out

Always worth reading the codes. I do not know if it will throw an error with a faulty MAF, maybe. You could disconnect it and drive without it to see if the consumption changes. If it does not change, then it is maybe faulty.

[cancunia]

Actually, I'd also be wondering about the EGR & boost. I think the code reading is a good start & maybe monitor the other items so far as possible without Lexia / Diagbox. If nothing turns up then it would be Diagbox to see what the ECU thinks is going on.

[Sol]

bad MAF readings don't produce any code, only disconnection will. The default map will be used if you disconnect it, so 400g/s at idle with no MAF hooked up and around 370-390 when using a working MAF.

You need to be able to read live data, not codes, to find a poorly performing MAF. This can be done with some diagnostic units or with DiagBox and a Lexia 3 interface.

[cancunia]

bad MAF readings don't produce any code, only disconnection will. The default map will be used if you disconnect it, so 400g/s at idle with no MAF hooked up and around 370-390 when using a working MAF.

You need to be able to read live data, not codes, to find a poorly performing MAF. This can be done with some diagnostic units or with DiagBox and a Lexia 3 interface.

Not always,  but is often the case that a duff MAF will not produce a code. For example, my first 1.6 M59 had the EML on when I bought it (the seller had forgotten to tell me about it before I travelled 100 miles to see the car), it was a MAF problem according to the code & went away when I replaced the MAF. I think reading the codes is a good starting point as there may be other issues
Totally agree the point about needing live data, as it may well be something else in this case.

[Sol]

Yep right enough Cancunia, could be either way round.

[munkey]

Well I disconnected the MAF and did my usual M4 stint and the MPG is pretty much the same, it drives almost the same maybe slightly under powered lower down in the rev range but not really noticeable. I was surprised the EML didn't come on with it disconnected.

I can't really justify shelling out on a Lexia right now but its sounding like it is the MAF. Anyone had any expearance with the ebay knockoff replacement sensors for £30?

[cancunia]

Have you managed to get hold of a code reader, just in case there's something else wrong?

For my 1.6HDi I bought a used one from eBay, it's a bit of a lottery but it worked fine for me.