MPG problems

[Abyss]

I have bought a 58 plate Honda Accord 2.2 diesel (145ps version).

Quote combined MPG: 48
Actual I am achieving: 39 - This is 90% motorway mileage.

I have done 600 miles over the last week, mainly motorway, resetting the MPG counter when I bought the car and after 300 miles. Something really doesn't seem right, I averaged 47mpg in my D5 Volvo that is quoted as 42mpg combined!

Any ideas? Or does anyone have a 2.2 Accord that can share their real world MPG?

 

[davy89]

From what I remember someone saying those diesel accords don't make the expected MPG.

 

[Nickyyy]

Has it been serviced recently? Cars tyres inflated to the right levels?

 

[Abyss]

Serviced by the garage when I picked it up. Tyres are inflated to exactly what the book says.

 

[Rich_L]

Measure your mpg manually using a spreadsheet or phone app too - could be a difference there. Also are you driving 10mph faster in the Honda?

 

[Kenai]

Quote combined MPG: 48
Actual I am achieving: 39 - This is 90% motorway mileage.

Average speed on combined cycle test: 38mph
Top speed on combined cycle test: 75mph (for a matter of seconds)

The majority of the combined cycle is spent sat at about 45mph or so. Drive around constantly at 45-50mph and you'll probably get 48mpg easily.

 

[Abyss]

I haven't worked it out exactly at the pump, but I am already well into my second tank of fuel after 600 miles and put in over £60 when I filled up. so I can't be getting anywhere near what I did in the Volvo.

I am actually driving slower in the Honda, I certainly did for the second 300 miles. On the way back home on the A1 I drove well within the speed limit all the way to see if it helped.

 

[Abyss]

Average speed on combined cycle test: 38mph
Top speed on combined cycle test: 75mph (for a matter of seconds)

The majority of the combined cycle is spent sat at about 45mph or so. Drive around constantly at 45-50mph and you'll probably get 48mpg easily.

Interesting. What about extra urban where it says I should be getting 50 something?

 

[Kenai]

Interesting. What about extra urban where it says I should be getting 50 something?

Apologies, it's the extra urban cycle that I just described as combined. The combined has a much lower average but contains more stop start.

This graph is in kph but should give you an idea

The entire graph makes up the combined test, 'Part two' makes up the extra urban test and the urban test is clearly marked.

As you can see, none of the tests contain anything which even remotely resembles travelling at 70mph-80mph for an extended period.