Technical Fuel economy concerns

[grarrgrarr]

Hi all,

I just bought a new Fiat Doblo Maxi (105 hp 1.6 Multijet 16V) and I have so far driven it about 1200 km.

It is capable of Euro V with DPF and Start/Stop but I believe that in Singapore here our regulations are still on Euro IV so my model does not have DPF and Start/Stop.

Right now I average 6.8 l/100km (34.5 mpg) which is quite poor, but I have noticed that my idle fuel consumption is slightly high for a diesel.

With a ScanGauge, it displays my idling fuel consumption at around 1.6 LPH with AC on, sometimes dropping to 1.4 LPH (i think with alternator inactive?).

This is even worse than my previous petrol vehicle, and I'm wondering if its due to it being a new engine, or maybe the ECU is not tuned right?

On a trip with 90% highway road I can only get the consumption down to 4.6 l/100km at best.


Would you think this is out of the ordinary?

 

[TwyRob]

I would wait another 3000km until I got worried. It's not even run in yet!

 

[grarrgrarr]

Thanks so much for your reply, looking forward to see what its "real" consumption is like when its done with the run in

 

[Yobbo]

grarrgrarr, I am not totally happy with the economy of my Dobby either. Mine is a 105hp Euro 5 with the start stop. This is my 8th diesel car and without fail they have all produced 48-55mpg long term and two of those had 140-150hp.

My Dobby is doing 42-43 mpg and I am baffled as to why. I never drive it over 65 mph and it does lots of long journeys. I know its aerodynamics are not great but it isn't a heavy car either so I would have expected in excess of 45mpg with the high 6th gear which means the car cruises at under 2000 revs.

There was an increase in engine power and torque at about 10,000 miles as the engine has freed up, but the economy has not shown any real improvement.

For me its not a show stopper as its not my main car and economy was not my main reason to buy, but I would like it to be a bit better with its fuel.

 

[grarrgrarr]

I wonder if the engine free-up at a certain mileage is something programmed into the ECU, or is it just the natural effects of the mechanical run in?

Your car should be heavier than mine by a fair bit as mines a cargo version sitting at 1370kg empty.

65mph is quite fast.. over here I cruise around 45 mph.. A van chassis is sure to suffer from high amounts of aerodynamic losses once you go high speed.

I also decided to raise tyre pressures a bit, mine is specced for 2.7 bar front and 2.7 bar / 3.6 bar rear according to cargo load. I'm doing a tank with both ends to 3.6 bar to check out the results.


Do you track your fuel-ups on fuelly? I don't have 5 posts yet so I can't post my link.

h_ttp://www.fuelly.com/driver/grarrgrarr/doblo

 

[antama]

my 2012 1.6 active,s trip computer tells me its doing 43.7 mpg avg ,how ever brim to brim calculation results in a 47 .3 avg, the mileage is now 6,700 miles (in two months ! )

 

[Yobbo]

Thats interesting, perhaps the computer is pessimistic. I will do a brim to brim to see if I get the same result.