Low Mpg on New Car - Advice?

Only

Guys, I have a new Citoen C4 Grand Picassa - have it a couple of months and was doing a long journey today so decided to fill the tank and check the mpg.

I did 494km and it took €51.20 to refill it afterwards at 139.9c/l - anyways I just checked and I'm only getting 38mpg:eek:.
Its a diesel car and it was from Mayo to Dublin and back again - very little driving in Dublin itself. The only thing I can think of is that I used the cruise control on the way up and down on the Motrway to Galway - would it affect it that much???
The listed mpg for intra-urban on the Citroen website / brochure is 56mpg ... any advice please???

cruizer101

what speed were you doing a lot of people don't realise how much of an effect higher speeds can have on fuel consumption, and I don't even mean speeding.

crosstownk

You should be getting better than that. What did the trip computer indicate?

Is it a manual or EGS?

ottostreet

is 38mpg that bad for a car that size?

Atlantic Dawn

Did you have air con on, did you have it in the highest gear when driving?

Gary ITR

Aircon, windows being open and tyre pressure to name a few things can have an effect on MPG. Was there much extra weight on board?

Only

No Air Con on
No windows open
Only 2 people in the car - nothing else so no heavy load
Driving in highest gear all the time

We were driving at the max speed limit on the motorway at least - maybe a bit above at times.

I didn't set the trip computer so I don't know what it said ... tbh, am still getting to grips with all the settings / gadgets:o

The listed mpgs for our particular model car are:
Urban 48.7
Extra Urban 61.4
Combined 56.5

This is the first time I've checked the consumption so not sure what its doing on short trips but will definately be checking at the next fill

Am I right in thinking that the cruise control couldn't have that much affect - is any at all??

That's not great mpg at all for the driving you were doing, I would have thought you'd have seen 45+ no bother on that sort of usage. However the little above 120kph could well explain it

Just for comparison, a 1992 W124 Merc E250 averaged 36.33mpg for me over 3900 miles, mainly Cork to Galway and return runs at a bit over limit and then the rest in and out of work (couple of miles).

Only

RoverJames wrote: »

That's not great mpg at all for the driving you were doing, I would have thought you'd have seen 45+ no bother on that sort of usage. However the little above 120kph could well explain it

Would it hurt it that much?? Fair enough if it would - just got a bit of a shock when we filled up:rolleyes:

unkel

Only wrote: »

I did 494km and it took €51.20 to refill it afterwards at 139.9c/l - anyways I just checked and I'm only getting 38mpg:eek:

Are you sure your tank was as full to start with as when you filled it up at the end? My guess is that it wasn't. Only time will tell though, keep filling it back up and keep calculating the MPG. Once you've done it a good few times, the inaccuracies in how full the tank was will even out

On a trip like that you should be looking at 50-60 MPG in your car I'd have expected. Sure I would have done better than 30MPG in my 3.5l V8 petrol automatic BMW 7 series

If you were doing 135kph it could well effect it Depends how much over 2200/2400rpm you were going when in top gear.

Mr Benevolent

Best efficiency would be around 100kph.

TheAnswer

What sort of mileage do you have on the car? I remember when I got my new diesel I was shocked at how bad the fuel consumption was until the car had around 8 thousand kms up, then it improved dramatically. Cruise control should actually help your fuel consumption as you (me anyway) tend to just leave the car alone instead of giving it bursts up to 130-140.

allthedoyles

My car recently failed the NCT due to wheel bearings and track rod ends .

When I got these fixed and car passed NCT , - I noticed a massive improvement in fuel consumption.

crosstownk

Confab wrote: »

Best efficiency would be around 100kph.

It's actually better at around 80/90km/h but is slow going.

I drive from Dublin to Castlebar regularly in a Citroen 1.6HDi (various models) and would get somewhere between 5 - 5.5 l/100km. I use the cruise control whenever I can.

Use the live fuel consumption monitor on the trip computer to see your instantaneous consumption.

Damien360

As an example my mondeo diesel 1.8 does 48mpg if I drive nicely and keep it at or under 100kmph. I keep climate control on all the time and use cruise control a lot.

But...if I drive on motorways for the week and even when I am being nice to it, it munches fuel and I get 45mpg. If I drive as I normally drive on motorways at 130 to 140, the very best I get is 43mpg. Even if I drive the ****e out of it, it returns 43mpg.

These figures have been consistent over the 3 years I have had the car and 180,000kms.

Your figures of 38mpg are not good at all even for a big lump of a car like yours.

allthedoyles

allthedoyles wrote: »

My car recently failed the NCT due to wheel bearings and track rod ends .

When I got these fixed and car passed NCT , - I noticed a massive improvement in fuel consumption.

I'd be thinking a C4 that's a few months old would be spot on in that regard.

Only

Thanks for all the input guys!

Theres only 6000km on the clock so maybe it needs breaking in
Was probably going 140kph for a fair bit coming down but not going up (weather was brutal for driving!)

Damien, going on how yours preforms mine was VERY bad! Really am shocked - I had a 07 Citroen before this (Grand Picassa too) and I definately got better mileage out of it on long trips than this one and it would have been driven more or less the same.

unkel, am 100% sure it was full at the start and at the end - filled up both times at the exact same pump in the same filling station and filled until it 'clicked' that it was full both times so sure it was the same fill both times.

Going to do a bit more checking and see how it goes the next couple of weeks and if it doesn't improve I think I'll be going back to the dealer

Raskolnikov

How new is it? I would expect that the consumption on a brand new car to be that bit worse than a car which has done a couple thousand miles.

Only

Only 6,000km on the clock - bought end of February

merc3ps

I think that 140kph will affect things. Also, bad weather driving can cause higher mpg simply due to driving style.

Also, some people are simply unaware of their driving style. You can accelerate from 80-120 on the motorway in heavy traffic in two ways... gently, or foot to the floor.

Also.... alot of motorways actually have many long inclines which eat more fuel.

Those quoted manufacturer MPG figures are all done under test conditions.

My father has the same car 1.6Hdi and he gets about 48mpg average but is a "gentle driver"... so if you are doing 140kph on the motorway I can see it dropping lower.

colm_mcm

allthedoyles wrote: »

My car recently failed the NCT due to wheel bearings and track rod ends .

When I got these fixed and car passed NCT , - I noticed a massive improvement in fuel consumption.

Given that its a brand new car, I doubt this is the case here.

trad

140km/h is approx 87 mph. Why would you expect fuel economy at that speed?

mullingar

IMO, A C4 Grand Picasso @ 140kmph will only get max 35mpg due to wind resistance as its such a tall car.

If you double your speed the wind resistance actually quadruples! - 70kmph has only 1/4 the air resistance of doing 140kmph.

Drop your speed to 110-120kmph and you should see around 40-45mpg

Only

Thanks for that mullingar - I was just a bit surprised thats all - had no idea it could affect it that much - think OH will have to slow down a bit:rolleyes: ... mind you, its rarely we get on a Motorway so this shouldn't happen too often.
Going to clock it for the next while and see what we're getting.
Checked the trip computer this morning on the way into work and its varying between 6 and 7.5l / 100km - still looks a bit high to me - that was about 6 miles on country roads.

unkel

Only wrote: »

I was just a bit surprised thats all - had no idea it could affect it that much

It would start to make a considerable difference at speed. But were you really doing 140km/h or more for most of the time? (140km/h in real life is about 150km/h on the speedo of many cars). Or did you not drive at a constant speed - changing your speed between say 120km/h and 140km/h all the time would be terrible for fuel consumption.

Only wrote: »

Checked the trip computer this morning

I'm gonna stop you right there. Trip computers are notoriously unreliable. Never mind what it is telling you

Leonard Hofstadter

Only wrote: »

unkel, am 100% sure it was full at the start and at the end - filled up both times at the exact same pump in the same filling station and filled until it 'clicked' that it was full both times so sure it was the same fill both times.

You can normally squeeze another few litres (in my car I can get another three or four litres in, although it's almost coming out of the flap at that stage:D) in after it makes the clicking sound, so you didn't quite do the brim it, drive it, brim again and repeat test properly;)!

unkel

captainspeed wrote: »

You can normally squeeze another few litres (in my car I can get another three or four litres in, although it's almost coming out of the flap at that stage:D)

In the 928 the clicking starts when the tank is only a bit over half full. Weird but true!

Del2005

captainspeed wrote: »

You can normally squeeze another few litres (in my car I can get another three or four litres in, although it's almost coming out of the flap at that stage:D) in after it makes the clicking sound, so you didn't quite do the brim it, drive it, brim again and repeat test properly;)!

The OP filled to the same level both times, they even used the same pump, can't see it getting more accurate then that.

It's not a good idea to be filling the breather/expansion pipes in the tank with fuel.