Fuel consumption

[FrenchMike]

"The best way to get the most miles per gallon is gentle acceleration"

Totally agree with you Simon . interestingly one can Watch it by using the OBD
in 4 (Momentary Consumption)

Merry Chistmas to all of you

Mike

[MSS]

Our CDT manual saloon has averaged just below 47MPG over 40k miles. It has never dropped below 42MPG.

What am I doing wrong to be consistently getting such good MPG - apart from keeping the car perfectly maintained and using it mostly for 10+ mile journeys so that the engine reaches normal running temperature?

Originally Posted by marinabrian

........... If you worry about fuel consumption, owning either a ZT or 75 is not really for you

Brian

I will agree with that man - as it is Christmas.

[SD1too]

Originally Posted by mss

What am I doing wrong to be consistently getting such good MPG ...

Nothing "wrong" of course, but you've highlighted another reason for variable figures:

... has averaged just below 47MPG over 40k miles.

Many people posting on this subject are using far, far shorter distances. Some will get figures which are more akin to instantaneous fuel consumption than a true average. For example, those who make their judgment on a single motorway journey of several hundred miles are bound to achieve a favourable figure if the trip computer is reset immediately beforehand.

In the recent cold weather I've seen a few diesels idling in car parks whilst the driver tries to keep warm whilst passing the time on a smart phone. This consumption won't show up on the trip computer*, increasing its inaccuracy (it will on a brim-to-brim though ).

There are so many variables.

Simon

* I haven't checked this on my 75, but it is true for our other cars.

[clf]

Originally Posted by SD1too

In the recent cold weather I've seen a few diesels idling in car parks whilst the driver tries to keep warm whilst passing the time on a smart phone. This consumption won't show up on the trip computer*, increasing its inaccuracy (it will on a brim-to-brim though ).

There are so many variables.

Simon

* I haven't checked this on my 75, but it is true for our other cars.

I have done this, after resetting and driving about a mile, then idled for about 30 minutes to allow the car to reach temp, the IPK consumption figure falls (very very quickly after such a short reset lol) more fuel used with no miles added kills that average.

[Christopher Price]

Originally Posted by 2.8jonmy

So far per tank I have managed 32(all local) 38(some long trips)and 35(mostly local) mpg from a manual cdti tourer, most journeys have been local and the thing is rarely fully up to temperature.
My MAF sensor is a bit suspect as it had all the hall marks of poor exceleration to 2k revs until I disconnected it, then I refilled the tank and discovered my hideous fuel economy. At that point I cleaned the sensor and reconnected it with an improvement over the original stepped power but not as good as running with no maf connected and no apparent improvement in fuel consumption.

They are less economic than I had hoped.
Jon.

That does sound low for a manual, but if your MAF is knackered (which it sounds like it is) it will knock the mpg down. If you want to maximise your cars mpg, then treat it to a new genuine Bosch MAF, (don't be tempted by a cheap Chinese one, as you may as well just set fire to the money in your back garden) and then treat your car to a health check at one of the T4 Specialists and the 160 re-map, which both improves the performance and economy of the car.

[Mr bountyfull]

My input after buying Brendan P's red manual with 127k on the clock. I have covered just under 700 mile to date with a test on mpg started 372 miles ago. As with all diesels purchased I treat the car to a EGR clean and a fuel system cleaner. After filling this morning with as said 372 miles covered and the mileage display showing 44.1 mpg the actual brim to brim was 50.27 mpg. More than happy, this was with 80% motorway sitting at 70mph by display with the cruise on and assorted A road driving making up the remainder.

[COLVERT]

Originally Posted by Mr bountyfull

My input after buying Brendan P's red manual with 127k on the clock. I have covered just under 700 mile to date with a test on mpg started 372 miles ago. As with all diesels purchased I treat the car to a EGR clean and a fuel system cleaner. After filling this morning with as said 372 miles covered and the mileage display showing 44.1 mpg the actual brim to brim was 50.27 mpg. More than happy, this was with 80% motorway sitting at 70mph by display with the cruise on and assorted A road driving making up the remainder.

My diesel is showing a fraction less mpg than yours.

I'm happy with the MPG I get and your figure shows your engine must be in good condition too.-----

Unfortunately for the owners of the auto box the results are nowhere near those of the standard box.

[Mr bountyfull]

My two previous diesels were firstly a ZT manual and no matter what i did I never seen north of 49mpg. The second was a manual 75 also never seeing much more than 45mpg. As has been said on the forum they do seem to vary a degree or to. I think the 195/65/15 are helping with the latest 75 as the ZT and the earlier all ran with 225 rubber - extra grip extra resistance?

[Mr bountyfull]

Update - now with T4 fix. The car is now more swift where I want it 50-70mph but more importantly the car is now giving just shy of 60mpg (over 59mpg brim to brim measured) with the same routes and speeds. The 750 mile a week round trip is 66% motorway sitting at a indicated 70mph by speedo and 66mph by GPS.

Delighted with my visit to Phil-T4

[MSS]

I wasn't aware that the T4 fixed aything - I thought it provided a diagnostic and configuration capability.

What is a T4 fix?