How Economical A Citroen C4 1.6Hdi 2006? Share Your Expereince

[arak81]

I bought this diesel car (C4 1.6HDi 2006) hopping that it will be very economical and there is a rumour in the market that diesel car is economical. However after driving in the city for last couple of days (10 miles radius in London which includes dual carriageway as well) I did the math and I was staggered that i got only 29mpg. is it normal?

about a little history of the car- Last Servicing was done in 59,500 and the car is now its 62,500. next servicing is due after 9000miles. DPF fluid has been topped up 4/5 days ago. I have fill up the tank with 60litters of diesel and then used 200ml STP diesel  injector. then I did the test and came up with this staggering result. guys please share your experience and also advice me how to get more mpg with this car.

[paul.h]

If you want to improve your mpg then you will need to not drive in towns and if possible drive when the roads are not busy, do not race between traffic lights, drive smoothly, lift your foot off the accelerator as soon as you realise you are going to slow down, drive in as high a gear as possible (for a diesel it should be ok to change up a gear at about 1500 to 2000 rpm whereas a petrol will need higher rpm). The stopping/starting/using low gears in a town prevents getting a decent mpg.

 

The official mpg will be in your handbook but from a 2005 C4 brochure for the 1.6 hdi 110 bhp engine with a 5 speed manual gearbox but no dpf gives : 47.1 / 70.6 / 60.1 mpg urban/extra urban/combined. Our 2008 C4 with this engine and without a dpf, gave about 52 mpg average but most of the mileage was motorway and it was the town bits that knocked the economy down to this from high 50s on the motorway.

[Johndouglas]

i got only 29mpg. is it normal?

No - 29 mpg average isn't normal. But over how many miles? Maybe you didn't give it a long enough test. Cold starts, a lot of intermediate gear driving and a heavy right foot can all add to poor consumption figures. Incidentally, if your car has only done 62K miles, why did it need the Eolys fluid topping up?

[arak81]

I drove around 146 miles since i filled the tank to the full and my top 4 bars is gone.I spoke to Citroen about dpf fluid top up and they said its not unusual to require DPF fluid topped up in cars 61000miles.

[paul.h]

If your calculations are based on the bars on the level gauge, I would wait until you fill up again and see how much you can get in the tank to get it full up again as when you started the calcs. I do not know how many bars there are but if say there are 10 bars for 60 litres, then 1 bar could be about 6 litres but it could be 0 to 6 litres for the bar to be lit or go out. eg 4 bars have gone out could be just over 12 litres up to 24 litres.

[arak81]

My calculation was very simple and accurate. I have 12 bars and tank capacity is 60ltrs..so each bar represents 5litters. I filled the tank to the top when last two bars were flashing..according to the manual last 2bars flashing mean i have 7litters fuel left in the tank..so i started fillin the tank and its automatically cut off when 53 litters have been poured. 2bars were gone in 1st day after driving 79miles and another two second day after driving 67miles.

[paul.h]

If your calcs were accurate to the number of litres used, then 4 bars are 20 litres and 4.546 litres are 1 gallon. So 146 miles using 20 litres (4.40 gallons) gives 33 mpg. So doing the calcs again has gained you 4 mpg. However, I would still do the calcs again once you fill the tank back up and use the amount of fuel put in.

[arak81]

whatever it is..but still very unacceptable. today another one bar has gone (total 5bars gone out of 12bars) and odometer reading is 202.. very unhappy with the bullshit diesel economical car. thanks to Johndouglas for the tips though.

[paul.h]

This latest 5 litres have given you 56 miles, so 51 mpg this time. Are you still driving round London ? What mpg is the trip computer showing ?

 

What mpg did your last car give you for similar trips  and was that a diesel or petrol ?

[arak81]

My last car was Kia Picanto..petrol 1.1 and i used to get almost 50+ mpg for combined driving. yea, i am still driving around the london...anyway,i will keep eyes on the bar and will update you when next bar goes off.

[Johndouglas]

today another one bar has gone (total 5bars gone out of 12bars

I think you ought to stop gazing at your fuel gauge. They're not very reliable at the best of times. For the first 100 miles on the Cit.BX that I used to drive, the fuel gauge hardly moved, then over the rest of the scale, it moved quickly. You should brim the tank, make a note of the mileage, drive for 300 miles, brim the tank again, then divide the miles by the fuel bought.

 

Incidentally, my daughter drives a 1.6 C4 and after driving a 2ltr Xsara for 12 years, her comment was that she hardly ever puts fuel in it.

[arak81]

I am back to my topic again.

 

i have figured out how accurately mpg can be calculated. I have filled out the tank to the full (when the pump stop releasing fuel automatically) and drove to Cambridge and cam back to London. i put my trip metre to Zero before setting out the journey. So once i came back to London it was 151 Miles. So i have filled the tank to the full from the same petrol pump and it was exactly 17.1 litres. So if i calculate, mpg is only 40.

it is disappointing..because the car has had its full service last week and the journey i made was all motorway.

[arak81]

Can anyone tell me if DPF blocking can cause more fuel. My C4 is really consuming too much fuel. its almost like 20mpg on average.

My DPF warning sign certainly comes on dashboard when I go to motorway and it goes away after few days. so I am guessing Diesel Particulates are building in the filter and a very little are cleared off followed by a dpf sign in the dash.

I did a lot of research and it seems the car should regenarates itaelf while driving 15mnts in gear 3 for 40 mph. its never happening..

 

So what would be my best action against this dpf..to get a professional to clean it. or change it with an after market one (seen one on ebay for £130), or live with it as this error is not causing any problem except fuel consumption.

[alfsc4gp]

Not sure if it's your DPF that's to blame but it is possible to clean the DPF manually, using a hosepipe to flush it out (seen a video showing how to do it on youtube)...After raising the front of the car, placing it on axle stands and removing the engine undertray, you just undo the bottom exhaust clip and then undo the big steel circlip at the bottom of the DPF housing...The DPF itself can then be slid out out downwards out its housing (may need some effort to do this).  After cleaning, dry the DPF off with a hot air gun and refit to car.

My first suspicion is that you might simply have a badly clogged air filter instead as that can adversely effect fuel ecomony.  The standard Citroen induction system is a poor design to say the least (especially in regard to where the filter housing is located!)...I replaced the entire system (filter housing, pipes and  it's location) with a high flow custom version and I get about 10mpg more! (with my heavy right foot, that equates to about 75-100 miles more per tank full).

Also, check the bearings on your turbo...take the pipe off the turbo inlet and try gently wiggling the impellor side to side with your finger...if there is more than a mm or two of movement then your turbo will need replacing...A turbo in poor condition with reduce the power of the engine, causing you to use more throttle than you otherwise would, which in turn will increase your fuel consumption.