poor fuel consumption

bsabantam · 9th March 2019, 19:30

Hi I have a diesel 2.0 auto 2003 75 and the vehicle has enjoyed a full service history with 90,000 miles the vehicle drives very well with no smoke and an envious recent diesel emissions report. It is only returning 29 mpg on average taken on fuel used over many months, all filters changed including air and breather assy. I have had an oxygen power clean, that did improve performance for a short while and an extra 1.5 mpg.
Thinking of a remap has any member reported any real benefit?
I have checked for brake binding or grabbing and all ok.
last service included engine flush and diesel treatment added to help clean fuel delivery.
looking forward to my first meet up next week at the four ashes wolverhampton to meet other 75 owners, performance is ok although I understand that these cars can be a little lethargic , turbo is performing well when given a full throttle prompt, thanks.

minty2 · 9th March 2019, 19:49

Check intercooler and connections. Unsealed systems cause considerably poorer fuel consumption. Also check the MAF.

Quote:

Originally Posted by bsabantam

Hi I have a diesel 2.0 auto 2003 75 and the vehicle has enjoyed a full service history with 90,000 miles the vehicle drives very well with no smoke and an envious recent diesel emissions report. It is only returning 29 mpg on average taken on fuel used over many months, all filters changed including air and breather assy. I have had an oxygen power clean, that did improve performance for a short while and an extra 1.5 mpg.
Thinking of a remap has any member reported any real benefit?
I have checked for brake binding or grabbing and all ok.
last service included engine flush and diesel treatment added to help clean fuel delivery.
looking forward to my first meet up next week at the four ashes wolverhampton to meet other 75 owners, performance is ok although I understand that these cars can be a little lethargic , turbo is performing well when given a full throttle prompt, thanks.

marinabrian · 9th March 2019, 19:58

Depends under what conditions the car is being used, my wife's car averaging six miles per day produces 31MPG and that is a manual.

On occasion I've used it for a week or two, where the consumption decreases to around 47MPG

Brian

trikey · 9th March 2019, 20:08

Quote:

Originally Posted by marinabrian

Depends under what conditions the car is being used, my wife's car averaging six miles per day produces 31MPG and that is a manual.

On occasion I've used it for a week or two, where the consumption decreases to around 47MPG

Brian

And you didn't make the airbag light appear!!

Andy_with_a_screwdriver · 10th March 2019, 19:33

Quote:

Originally Posted by marinabrian

Depends under what conditions the car is being used, my wife's car averaging six miles per day produces 31MPG and that is a manual.

On occasion I've used it for a week or two, where the consumption decreases to around 47MPG

Brian

Our manual vauxhall 1.9cdti can behave in a very similar way

Having said that our 75 cdti auto tourer averages about 27mpg, so i'd be happy with 29mpg

I'm hoping it'll go up a bit when I get round to fitting the new thermostat.

willster · 10th March 2019, 23:35

Quote:

Originally Posted by Andy_with_a_screwdriver

Our manual vauxhall 1.9cdti can behave in a very similar way

Having said that our 75 cdti auto tourer averages about 27mpg, so i'd be happy with 29mpg

I'm hoping it'll go up a bit when I get round to fitting the new thermostat.

I get 36mpg most of the time with varied driving. Had genuine maf, 160 map. Currently 210 000

mbev51 · 11th March 2019, 06:35

If you are driving mainly in built up areas and not trying to be economical I would guess that for an auto it's not an outlandish consumption. Wintertime knocks fuel consumption down a few mpg.

Arctic · 11th March 2019, 21:36

HI Jeremy.
At the meet next weekend get one of the lads to go for a drive with you up to Gailey island and down to the M54 junction 2 island back to the meet with the OBD set at 19/7 then check the engine temp when you get back driving you are looking for around 85 -87 if below then stat is failing by opening early, therefore engine not getting up to full temperature which will not help when you are pootering about town etc

PS an upgrade will also help it can be done by post, super fast too I had mine done.

By superfast I mean it only takes three days in the post

COLVERT · 11th March 2019, 21:46

It's quite amazing to find the auto gives around 20 mpg less than the manual.--Where does all that power go to ???

The car's the same weight and I believe the auto has less acceleration.

marinabrian · 11th March 2019, 22:04

Quote:

Originally Posted by COLVERT

It's quite amazing to find the auto gives around 20 mpg less than the manual.--Where does all that power go to ???

The car's the same weight and I believe the auto has less acceleration.

It doesn't John, it's entirely dependent upon driving conditions

Around the doors an automatic is considerably poorer than a manual, however if the manual is driven for very short journeys, it will also be very poor.

Cars that are driven for short distance trips only, should be petrol over diesel, if nothing else, at least the heater will work nicely

Brian

9th March 2019, 19:30	#1
bsabantam Newbie ROVER 75 Join Date: Oct 2018 Location: WOLVERHAMPTON Posts: 16 Thanks: 0 Thanked 4 Times in 3 Posts	poor fuel consumption Hi I have a diesel 2.0 auto 2003 75 and the vehicle has enjoyed a full service history with 90,000 miles the vehicle drives very well with no smoke and an envious recent diesel emissions report. It is only returning 29 mpg on average taken on fuel used over many months, all filters changed including air and breather assy. I have had an oxygen power clean, that did improve performance for a short while and an extra 1.5 mpg. Thinking of a remap has any member reported any real benefit? I have checked for brake binding or grabbing and all ok. last service included engine flush and diesel treatment added to help clean fuel delivery. looking forward to my first meet up next week at the four ashes wolverhampton to meet other 75 owners, performance is ok although I understand that these cars can be a little lethargic , turbo is performing well when given a full throttle prompt, thanks.

9th March 2019, 19:58	#3
marinabrian MG ZT Join Date: Jan 2011 Location: Newcastle Upon Tyne Posts: 20,151 Thanks: 3,565 Thanked 10,837 Times in 5,718 Posts	Depends under what conditions the car is being used, my wife's car averaging six miles per day produces 31MPG and that is a manual. On occasion I've used it for a week or two, where the consumption decreases to around 47MPG Brian

11th March 2019, 06:35	#7
mbev51 Banned Removed Join Date: Dec 2013 Location: Removed Posts: 1,343 Thanks: 171 Thanked 315 Times in 223 Posts	If you are driving mainly in built up areas and not trying to be economical I would guess that for an auto it's not an outlandish consumption. Wintertime knocks fuel consumption down a few mpg.

11th March 2019, 21:46	#9
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	It's quite amazing to find the auto gives around 20 mpg less than the manual.--Where does all that power go to ??? The car's the same weight and I believe the auto has less acceleration.