Not the normal mpg question

[south_bound]

Until recently my mpg readings on the dashboard were quite close to the real readings from brim-to-brim measurements.  For the past few months though, the readings are much lower (up to 10mpg) than the real measurements which have stayed more or less constant.   The only thing I can think about is that I had the egr blanked and deleted in the summer and now the colder weather has kicked in this is reflected by the engine taking longer to warm up without exhaust recirculation and affects whatever the computer uses to calculate the fuel use.  Another thing is that whatever average reading I have when I stop the engine, the next time I start up it has dropped a lot and picks up slowly as the car warms up.

 

Its not really a big problem because the car runs well and the real mpg is as I would expect - its just the dash reading which is wrong.  I use this as an early warning if something is up eg. it dropped like a stone when the dpf packed up which caused me to investigate.  Just wondering what the cause is here and if anyone else has seen this.

[Dee_82]

winter always takes a knock to it, on mine I drop from about 59mpg to about 52, id expect it to go back up again as things calm down a bit with the weather.

[TomsFocus]

Mines shocking currently...  48mpg on the reader over this last week and it hasn't even been cold, no heated screen or anything, done a few longish drives as well (not long but not all town traffic)...starting to wornder if somethings really broken or if the trip computer is just having a laugh....

[Russ]

Dropped from 39 in the warmer months to 33! (100PS petrol)

[south_bound]

Thats why I always do the brim-to-brim check myself when filling up because I can't trust the dash computer readings - it used to be ok but as I said above recently they have been so far out as to be meaningless.  Does the Torque pro app allow real time readings of fuel use to be read to check against the dashboard values?

[TomsFocus]

Yeah I always do brim to brim as well, my last actual MPG was dead on 50, down 5 from summer, and nearly 10 from the same time last year but living in a different area.  Seems to be worse since the remap etc, which is odd seeing as I've always had better mpg after maps on other cars (306 HDi's and Golf TDIs), most expensive map I've ever had as well, disappointing tbh.  Maybe I'm just driving like more of an a***hole now haha.

 

[Dee_82]

I bet your putting your foot down more Tom, 1800-3000 in third is much better, it might be costing you more but it puts a smile on your face ;)

If I !Removed! about I can hit 60Mpg in the warmer months, usually means sticking to about 63 on the roads, lots of lift and coast, that's about 5mpg more than before any work was done

on a flat dry road I can get it up to 75mpg as shown by the instant display, bleeding off to about 65 on a small incline.

 

[TomsFocus]

It still feels slow tbh, but it's a heavy car for only 140bhp, doesn't give me any smiles either unfortunately.  Going from 130bhp to 180bhp in the Golf felt amazing, I ragged it everywhere I could and sat in rush hour traffic 4 times a day as well, easy 60mpg average plus smiles and covering tailgaters in soot!! 

But the Focus doesn't really feel any different, it is a bit quicker as I've timed it but still feels slow.  Doesn't help that of the few car mates I have, their cars are all considerably faster lol.  Still wish I'd bought the 2.0 and mapped that instead. ;)

[Dee_82]

Yeah, shes an heavy old girl with a fat ar$e, you could always look in to taking it a bit further, BMW injectors, new turbo, or go a bit further still

http://passionford.com/forum/restorations-rebuilds-and-projects/432786-300hp-fiesta-1-6tdci-project.html

If this chap can milk 300hp out of this without it blowing up ill be impressed, seems to have a lot of money to blow on it tho! :)

 

[TomsFocus]

It's far cheaper to buy something faster to start with...cheaper to insure as well, not to mention more reliable without silly mods.  I'm too old for all that now lol, been there, done that. :P

 

[wilto]

OMG I wish I could get that sort of mpg, my display at the moment is,,, wait for it,,,, 29.1 mpg, boo hoo, and that's driving like miss daisy. Wish I'd bought a ST now, 

[south_bound]

My remap a couple of years ago did help improve both fuel efficiency and performance, sorting out dpf and egr didn't hurt either so overall I am now getting about the same mpgs of 60-62 on average but with more grunt.  Wilto - we are talking about 1.6 diesel engine so can't compare with petrol which will never get anything as good no matter how hard you try.

[TomsFocus]

1 hour ago, wilto said:

OMG I wish I could get that sort of mpg, my display at the moment is,,, wait for it,,,, 29.1 mpg, boo hoo, and that's driving like miss daisy. Wish I'd bought a ST now, 

On the plus side your engine won't fill itself with carbon and break turbos, and you won't have to spend a grand replacing the DPF every 50k miles...    Plus when you bought it, you didn't have to pay a premium for buying an 'economical' diesel... 

 

I'll bet if you add servicing and repair costs to fuel and tax costs, you've spent less than I have....

[Dee_82]

To be fair tom, with the amount of money we have ploughed in to our Diesels, we could have probably brought a Petrol as well :)

Wilto, if I drove my diesel the way so many thought was safe, by driving lots of short town driving trips, my MPG would probably be not much better than yours, plus id have a wrecked car in 12 months for good measure. 

Diesels are good for distance driving, MOT to MOT I racked up about 18k miles this year :( my partner in her wee Petrol Festa clocked up an impressive 4000, thankfully I don't have to worry about those pesky DPFs :D.  Every car has pros and cons, trick is to know about them before you buy the car

DV6TED4 = Lesson learned!

 

[TomsFocus]

My car only did 2k miles and 3k miles between MOTs for 2 years before I bought it, no wonder the DPF had had it!!  I've done just over 11k in it this year though and that still isn't enough to make modern diesels worthwhile for me.

You're right Darren, I paid less for my GTi6 than I've spent on DPFs and remaps alone on this car haha!  

[wilto]

That was the reason I went for a petrol, only 5 miles to work, and about 100 mile's over the weekend and in the week, I had a 2010 astra 1.7 diesel for 6 months and was only getting high 30's out of that doing the driving I'm doing plus I had the dpf light on, on two occasion's, hated it.