AVG 22mg city driiving :( not right

[Shaz]

bought car 2 weeks back.
Vauxhall insignia 2012 auto 160 BHP

car drives fine.
however i had to fix left side wheel bearing was making noise on long journeys and short journeys.

Then did full main service. also flush and refill. Used BG additive best in market to engine flush and fuel system clean. I also pump using BP fuel.

I noticed since purchase there has always been this droining/humming noice, now i thought the wheel bearing fix would have covered this but
not the case. Separate issue. Now coming back to the droining noise. looking at Mo miah thread could be the boost control valve. so ordered and will fit.

Now even that i did the full service the car MPG is only achieving 22.mg maybe best 23. I rest trip 1 and 2 and from 35 starts dropping slowly and coming around 22-23. bit gutted not knowing where the fault could be and i did everything that i could to improve MPG. One last thing i could try is EGR clean maybe.

Had two new tyres fitted and all are pressured on 35psi.
i do feel slight lag on gear 1 and 2, which could be down to boost control valve. will eliminate this soon if that is the case.

[MJSROOFING]

First thing I would do is calculate the mpg your self, could it be that the abs sensor on the wheel bearing you've change is giving incorrect reading for the mpg.

[MJSROOFING]

Also, I have same car and tyre pressure on mine is 41psi.
Mine does min of 38 around town and 42 combined, up to 55 all motorway.

[Shaz]

your hurting me.

[Shaz]

how do you work out your own way with MPG

[Tdl]

Miles driven since filling tank divided by gallons of diesel will give u average.

[MJSROOFING]

Zero mileage and see how much mileage you do to X amount of pounds.
Think around 150 mile on twenty quid is good,maybe 40-45 mpg

My transit does 220 mile on £50, think that's about 30mpg.

[0011728]

Zero mileage and see how much mileage you do to X amount of pounds.
Think around 150 mile on twenty quid is good,maybe 40-45 mpg

My transit does 220 mile on £50, think that's about 30mpg.

What a garbage way of calculating your mpg as fuel costs fluctuate and mpg goes off fuel consumed NOT money spent. Brim the tank, zero the trip meter . Drive to half or quarter tank, then brim the tank again. See how many miles you have driven to the amount of fuel used i.e. the same amount of fuel you have just put back in

[MJSROOFING]

What a garbage way of calculating your mpg as fuel costs fluctuate and mpg goes off fuel consumed NOT money spent. Brim the tank, zero the trip meter . Drive to half or quarter tank, then brim the tank again. See how many miles you have driven to the amount of fuel used i.e. the same amount of fuel you have just put back in

Less of the garbage comments m8,

I was only trying to help someone here.
It's a approximately right I know this as I've been doing it for years, without getting a calculator out every time and putting odd amounts of fuel in at random times , I just monitor the amount of mileage I do to make sure there's no serious problems etc.

Feel free to calculate my findings and prove me wrong but I think you'll find you can't.

[chili]

i pretty much do mine this way and its never a million miles out. my car is a 2011 ecoflex 160 but its manual not auto

the drone like noise will be the boost valve which is a quick 10 minute job to fix

[2000rpm]

Is the car doing lots of DPF regens? When idling, a DPF regen will quadruple fuel consumption and when cruising it will double fuel consumption.
Have you looked at the top consumers menu which will show 'rear window demist' if a regen is in progress?
Have you tried giving the car a 30-minute run along a dual carriageway?

Diesels aren't ideal for town driving or short journeys - they'll suffer from DPF and EGR problems.

[Plym Ian]

Just fill it up and drive will you

Mine does on a run about 300 miles to £40

[Witty]

When you fill the tank, zero the trip counter, then the next time you fill the tank you will be able to calculate your fuel consumption.

Turn litres into gallons by dividing the litres by 4.54. This will give you how many gallons you have used.

Then divide the mileage by the gallons and hey presto, that will be your total mpg.

Hope this helps you work it out.

[MJSROOFING]

Is the car doing lots of DPF regens? When idling, a DPF regen will quadruple fuel consumption and when cruising it will double fuel consumption.
Have you looked at the top consumers menu which will show 'rear window demist' if a regen is in progress?
Have you tried giving the car a 30-minute run along a dual carriageway?

Diesels aren't ideal for town driving or short journeys - they'll suffer from DPF and EGR problems.

Totally agree with this statement.

My mpg go down by 2/3 during a short Regen so god knows what it would be like if it was doing it regularly or too often should I say.

[2000rpm]

Totally agree with this statement.

My mpg go down by 2/3 during a short Regen so god knows what it would be like if it was doing it regularly or too often should I say.

I should clarify that mpg halves when cruising during the 10-15 minutes of time that a regen is in progress, or quadruples during however long it takes to do a regen in slow/stop-start traffic. And a single ten-minute regen will drop the average for that whole tank by perhaps 5% (2-3mpg).
I had a diesel Astra in the past and as its mileage clocked up the DPF regens seemed to take slightly longer. When I first got it with 5k on the clock, regens took about 10 minutes in ideal conditions but when I sold it with about 40k on the clock the regen time had increased to about 12-13 minutes, possibly as ash accumulated in the DPF and/or the DPF became slightly less efficient at self-cleaning.

I see you have an auto diesel. Does the auto box drop down a gear or two to keep above the recommended 2000rpm during regens?