Huge spike in consumption??? Opinions??

[Yellow_Festiva]

Would like the opinion of the collective on this one as it has me stumped...

2010 LV, Diesel Focus... Consumption has been like clockwork for the first 60k km... always achieved factory figures or better with little effort.

Has all changed in the last 3 weeks. A few things have also been done to the car and one of those must be the cause.

Ok, a little history. I have added several posts to the 'Fuel Consumption of your Focus' using the many long distance trips I do under various loads.... Below is some of the more recent ones as a comparison:

Trip to QLD from Sydney in Jan this year:

Model: 2010 Focus TDCI
Generation: LV
Type: 2.0 PowerShift
Driving style: 20% City : 80% Freeway, 853km.
Fuel Consumption: 4.7L/100km (was at 4.4L till we hit traffic!)
Total KM's on the clock: 54k km
AVG speed:76km/h
Conditions: 2 occupants, meduim load, empty roof racks, space saver as well as full size spare, air-con on the whole time.

DTE - 122km. Was stunned! Did the drive from Sydney to Coolangatta and the consumption leveled out at 4.4L per 100, with an average speed of 84km/h. Hit Taree and from there to Kempsey it was 5-10km/h bumper to bumper which reduced the average speed to 70 and our consumption went from 4.4-4.9 :(. Kempsey to Coolangatta leveled the figures to what we have above.

So, I was hoping that the trip back would be a little more smoother, just to compare with going there:

Driving style: 20% City : 80% Freeway, 854km.
Fuel Consumption: 4.6L/100km
Total KM's on the clock: 55k km
AVG speed:79km/h
Conditions: 2 occupants, meduim load, empty roof racks, space saver as well as full size spare, air-con on the whole time.

Fully loaded:

Model: 2010 Focus TDCI
Generation: LV
Type: 2.0 PowerShift
Driving style: 20% City : 80% Freeway, 320km.
Fuel Consumption: 5.8 L / 100km
Total KM's on the clock: 35,000 km
AVG speed:75km/h
Conditions: 2 occupants, fully loaded with 150kg tools, fully loaded roof racks, probably another 80kg.

Ok.... So last night I pulled into my friends place in Melbourne after driving from Sydney, a trip I have done a few times now on a single tank each way no worries. This time it took a tank and 1/4....

My consumption would not go below 5.7L per 100!

My car was also configured to equal or better the 4.4l per 100 I achieved going to Qld:

No roof racks, Air-con never on, wheel alignment done the day before (the front was way out), no full size spare in boot on top of the space saver and new tyres pumped up 10% above factory specs to improve rolling resistance..

The car has just clicked over 62k km. In the last 2-3 weeks it has had the tranny serviced and software updated, diesel filter changed, new wheels and tyres fitted, roof racks removed, new rear brakes and wheel alignment.

I generally fill up at Shell opposite work, but seeing as I'm on holidays I have been using the local independant that is 12-14c/pl lower than the big names.

So, I thought it was dodgy diesel, if there is such a thing?? At 615km with 1/4 tank to go I pulled in to a BP and filled it to the top (as I did in the morning prior to departure).. Worked the consumption using litres / distance at around 6l/100... even worse than the computer... DTE read 833km when it should have been almost 1000 like it read on the QLD trip.

Got back on the freeway, waited 15 minutes for the fuels to mix and flush through the pipes and re-set the consumption. Within 10 minutes it settled back smack on 5.7 and didn't budge. Went down to 5.4 on an early downhill stretch but then back up to 6 to settle at 5.7...

After getting the service I was doing a lot of aggressive driving and I commented to my wife that it was the first time EVER we saw the average consumption go above 8. And it was very hard to make it go down again...

This has me stumped... my consumption has gone up 20-25% in 3 weeks.

I'm thinking tyres???? But to that extent?? I'm now getting consumption readings similar to when my car and roofracks are fully laden....

Had the factory tyres on till 60K, 205/55/16 and bought some LW Focus wheels / tyres off a Forum member and put them on. 215/55/16. Slightly taller (speedo is now 100% spot on) and 10mm wider.....

What gives??? Oh, my average speed going to Melbourne was 95km/h as I live 2km from the entry to the expressway so well and truly 'freeway' driving...

Lets see how we go with this,

Tanks all

Jason