MPG on 2002 406 estate mid 30s

[Doggy]

Round trip to Leeds today at what Mr TomTom reckons was 72 mph - average 47.1 mpg, which I reckon is pretty good given the freezing weather.
Even saw 47.9 for a spell.

FWIW both my 2.2 HDi's trip computers have been pretty much spot on, whether on standard maps, or with extra beans.

[nomadicbry]

Hi Latest update
I did the italian tune
Ran the car at just under the red for around 10 miles
Initially a lot of smoke came out the exhaust... i assume this was the crap burning off
this then stopped after a few miles

I have, since doing that, driven a round trip of 200 miles mostly motorway driving and the MPG was stilla round 36-39mpg range

is the next step a full service do you think?

cheers
Bryan

[6speedmanual]

I found the trip computer on my 110hdi to be consistent and only 2% optimistic over 50,000 miles.
I recorded every drop of fuel added and went to some lengths to ensure a repeatable process for brimming the tank.

I think where many real v computer mpg results go awry is in only comparing on one brim to brim, using less than the tank (brim to half to brim doubles the potential error) and diificulty. in good (repeatable) brimming method.

Très puzzled why my Xantia is not matching the mpg of my similarly engine and gearbox equipped 406. I can think of some reasons but not sure exactly the causes.

Peter

[paulb2004uk]

Hi,

Have you tried resetting the trip computer, I understood the MPG was average calculated over the last few thousand miles.
I'm getting 35mpg with an average speed of 16 mph. Don't you love driving in London.
If I'm going on a long run will do a reset of trip computer. When I last did this I averaged 55 mpg going to Yarmouth and back.

[nomadicbry]

Hi again
thought i'd post an update
Tyres at front had been worn down on teh inside so put teh car in for new tyres and tracking
apparently the front were fine but teh rear were way out

After some investigation suspensiona rms and bushes etc needed replaced and they set the rear tracking
also found the nearside rear brake had seized so i think we may have found the issue with the low MPG at least i hope so.

The wife picked up the car last night and said she instantly felt a difference which quite stunned her. Ive been working away this week so will reseet the computer again and see how it averages out over 500 miles or so

thre was a very early post asking if i was driving with the brakes on... I dismissed this, funny how it turns out to be not so far from the truth haha

Bryan

[piglet]

Bryan,
Mine is an 03 Hdi90 2.0 estate with Siemens injection.
Computer normally says 36-39 in winter but consistantly under reads by 10%.
I know this because I am sad and keep a spreadsheet of all my mileage, pump totals and computer readings.
Real life average is 42mpg.
I get a bit more in the summer and it went right up after I changed the oil.

wish I was getting 50mpg
Tim