Very poor mpg

[B6NHM]

Hi everyone. I've recently bought a 20061.8 tdci. When I got it I was getting about 37mpg around town. Thought this was a bit low so I put a new fuel filter on. I reset the mpg reading now all I seem to get is around 26mp. To me for a diesel that is very low. Any ideas guys? 

[JamesMalin]

I had similar issues with my '08 TDCI 1.8.

Firstly I had the filter inside the fuel tank changed as well as the fuel sender unit as it had a faulty sensor.

Also the high pressure fuel pump needed changing as it was working too hard and worn out.

Obviously this may not be the issue with your car but they are very much worth checking.

My mpg for that car was a regular 45-47mpg over the month for a full tank and getting 490-530 miles.


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[andypsp]

2 hours ago, B6NHM said:

Hi everyone. I've recently bought a 20061.8 tdci. When I got it I was getting about 37mpg around town. Thought this was a bit low so I put a new fuel filter on. I reset the mpg reading now all I seem to get is around 26mp. To me for a diesel that is very low. Any ideas guys? 

have you done an oil and filter change too

[B6NHM]

No not yet. But does my see how that would effect the mpg? 

[james_60]

Hi

Replace Air filter.

Are your brakes binding if they are thats a big hit on mpg.

Are you doing long journeys or short ones.

Stick some Millers ecomax in the tank (i use it at every fill) (cleans things)

 

Jamie

[B6NHM]

Brakes aren't binding. It's only really used for short trips. I'll pull the filter out tomorrow see what it looks like.  Cheers 

[mjt]

1 hour ago, B6NHM said:

It's only really used for short trips

I think that's the key to your problem. These engines take a long time to reach operating temperature because of the amount of iron in the block. It's likely yours is spending most of its time in the warm-up phase. To get a true idea of the consumption you need to reset the mpg again and take it on a good extra-urban run, 40-50 miles as much as possible in top gear.

To be honest, if your motoring is predominantly short trips a diesel is a bad choice.

[FatHead1979]

14 hours ago, mjt said:

I think that's the key to your problem. These engines take a long time to reach operating temperature because of the amount of iron in the block. It's likely yours is spending most of its time in the warm-up phase. To get a true idea of the consumption you need to reset the mpg again and take it on a good extra-urban run, 40-50 miles as much as possible in top gear.

To be honest, if your motoring is predominantly short trips a diesel is a bad choice.

+1

[Freddy42]

16 hours ago, mjt said:

To get a true idea of the consumption you need to reset the mpg again and take it on a good extra-urban run, 40-50 miles as much as possible in top gear.

To be honest, if your motoring is predominantly short trips a diesel is a bad choice.

A 10 mile run on the M42 at constant 3000 revs in 4th gear sorted our diesel.

[B6NHM]

Ok so took the car for a 20mile trip I got just shy of 50mg at around 65mph. To and fro work which is about 5 miles away I get about 38 mpg 

[spurswes]

Diesels need to be worked,they like motorway/duel carriageway driving.  Is it true my 1.8 petrol (09) need an average amount of motorway work because apparently 1.8 don't like short journeys either (which I'm not surprised). ?? 

[mjt]

1 hour ago, B6NHM said:

took the car for a 20mile trip I got just shy of 50mg at around 65mph

That sounds about right based on what I used to get from our 1.8TDCi.