MPG not as good as I had hoped for

Ted_striker · 10-07-2006 1:38pm #1

I've started driving a '98 astra estate 1.7 diesel ,I haven't really had a chance to test the mpg on it yet but it seems to be a little heavier on juice than I was hoping for,Would a good service rectify this or does it need some extra attention ,What kind of mpg should I be expecting ?

Eoin · 10-07-2006 2:06pm

The figures here seem to suggest 44 - 58 MPG depending on the model, but those figures are usually best case scenario.

I'm having the same problem with my diesel - getting about 40MPG (without a heavy right foot), where as the official figures are 49MPG. I'm not in traffic a huge amount either, so was expecting better mileage.

How long have you had the car? I would imagine that if you are new to diesels as I was, then it may take a while getting used to the earlier gear shifts etc?

kluivert · 10-07-2006 2:34pm

Change the fuel filter and the air filter. Make sure the tyres are infalted properly.

My Astra use to drink petrol (1.4) but at 89k miles the economy is getting better I think.

I have found that the car doesnt like hard fast acceleration, it has the power (1.4) to do it but you can see the petrol gauge go down, then back up :rolleyes: .

The car doesnt bendy roads either, I took a trip from Monaghan to Waterford and got 45mpg - motorway followed by straight-ish roads.

I only get 38 mpg where I live, too many twisty bendy roads.

What year are your cars.

The new Astra fuel economy is far better than the old models.

1 Gallon = 4.544 Litres

prospect · 10-07-2006 2:35pm

Check your tyre pressure is right.
Are you going around with your air-con on constantly?
A service would help.
1st, 2nd & 3rd gears are the killers, get up to a good cruising speed ( about 55mph) and try to keep the rev counter at about 2400 rpm.

Owen · 10-07-2006 2:38pm

FYI, most of the mpg figures claimed by manufacturers are done on days with very little wind, on a test track, with cruise control on. I can get 48mpg in my 1.6 Petrol MINI if I replicate those conditions (Minus the track naturally), but most days because of my spirited driving I'm luck to get 25-26 mpg. Fun is inversly proportional to mpg

Ted_striker · 10-07-2006 3:11pm

Thanks for yere replies ,I've only been driving the car less than a week and have always had petrol cars before that so maybe when I get a better feel for the car and give it a good service things should improve .

mik_da_man · 10-07-2006 3:24pm

ned78 wrote:

Fun is inversly proportional to mpg

LOL - Very true, i found when driving my mates EVO 7 hard you could see the fuel needle dropping!!:eek:

Ernie Ball · 10-07-2006 3:50pm

If you live in Dublin and commute in your car, the traffic is probably the reason for your poor mileage.

Eoin · 10-07-2006 3:57pm

Ernie Ball wrote:

If you live in Dublin and commute in your car, the traffic is probably the reason for your poor mileage.

Not too sure, I travel off peak and not stuck in traffic all that much. I think maybe my right foot is not as light as I had thought

el tel · 10-07-2006 4:14pm

If you do what Kluivert and Prospect suggest I'd imagine that you should be seeing 50mpg no sweat with your car.
(BTW is it a TD, TDI or a D? Sometimes people buy older non-turbo diesels and expect wonderous fuel economy and fab performance but they can often be a little disappointed)

Eoin · 10-07-2006 4:31pm

el tel wrote:

If you do what Kluivert and Prospect suggest I'd imagine that you should be seeing 50mpg no sweat with your car.
(BTW is it a TD, TDI or a D? Sometimes people buy older non-turbo diesels and expect wonderous fuel economy and fab performance but they can often be a little disappointed)

It's an early 320D, but could probably do with a little tuning. Apparently the Air Mass Meter can be an issue on them.

maidhc · 10-07-2006 5:09pm

eoin_s wrote:

It's an early 320D, but could probably do with a little tuning. Apparently the Air Mass Meter can be an issue on them.

Are you just holding the gears too long. Peak torque in a diesel is normally somwhere above 2k rpm, and in normal driving it makes sense to change up around then.

In an Avensis my mother gets 41mpg, I get 47 in the same car on the same roads.

Eoin · 10-07-2006 5:13pm

maidhc wrote:

Are you just holding the gears too long. Peak torque in a diesel is normally somwhere above 2k rpm, and in normal driving it makes sense to change up around then.

In an Avensis my mother gets 41mpg, I get 47 in the same car on the same roads.

There's a very good chance that's what's happening - I'm probably still in "petrol mode" after the my last car - especially as the Alfa peaked much higher.

MPG not as good as I had hoped for

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