Citroen Xantia (1993 - 2000) - 1996 1.9td estate extremely poor fuel economy

Honest John Back Room » Technical matters
View Threaded
Tue 18 Mar 2008 23:33
1996 1.9td estate extremely poor fuel economy - alfacossie
Hi everyone,

First time post here but from what i see you all know your stuff.

I have a 96 xantia 1.9td estate and the fuel ecomomy is shocking.

I have done this several times now and getting the same results each time, i am filling up with diesel and putting in 68 litres. (which is 15 gallons) and the most i have had out of a tank is 397 miles. i have even tried totally unladden apart from me with very light acceleration and not going over 2000 rpm this got me to the 397 miles.

This equates to 26 mpg!!!! only 4 miles better than my mitsubishi evo!

i have checked for leaks through out the system and all is well so does any one have any idea what is causing it to be so amazingly bad?

cheers

paul
Reply | Report as offensive | Link
Wed 19 Mar 2008 00:23
1996 1.9td estate extremely poor fuel economy - Screwloose
paul

That does seem very low; does it black smoke? Have you ever seen oiliness on the bodywork?
Reply | Report as offensive | Link
Wed 19 Mar 2008 09:19
1996 1.9td estate extremely poor fuel economy - Peter.N.
Does it start and pull OK?
Reply | Report as offensive | Link
Wed 19 Mar 2008 11:28
1996 1.9td estate extremely poor fuel economy - Olaf_the hairy
Hi,
I own a 1997 1.9 TD hatchback which up until last month was also drinking like a fish.
When I investigated I found two major causes.
First was leaking intercooler hoses especially the turbo inlet to intercooler hose which had almost blown off due to jubilee clip not tight enough.
Second problem was front brake caliper guide pins were sticking and causing the brakes to bind. Also as the handbrake operates on the front brakes which means the cables have to flex with the steering, any damage to the cable sheaths often means dirt and corrosion builds up in the cables which then binds up - in short the handbrake stays on just enough to make the engine work harder.
Whilst checking the brakes I noticed the pads were not releasing due to the raised locating pip on the pad backing plates were not aligned up with the notch in the piston.
As a result of the brake cleanup and adjustment my economy means I normally get 580 to 627 miles from a full tank.

To summarise raise each wheel and see if brakes are binding. Rear brakes can also bind up.
Olaf
Reply | Report as offensive | Link
Wed 19 Mar 2008 12:57
1996 1.9td estate extremely poor fuel economy - mjm
I don't know whether the estate has a different fuel tank to the hatch but even running on petrol fumes I have never managed to get more than 58 litres into the tank. Your 68 litres seems a bit high.
Reply | Report as offensive | Link
Wed 19 Mar 2008 13:44
1996 1.9td estate extremely poor fuel economy - oldnotbold
When was the fuel filter last changed?
Reply | Report as offensive | Link
Wed 19 Mar 2008 14:02
1996 1.9td estate extremely poor fuel economy - Whisky
even running on petrol fumes I have never managed to get more than 58 litres
into the tank. Your 68 litres seems a bit high.


Xantia's are 65L arn't they? same as the 406/405?
Reply | Report as offensive | Link
Wed 19 Mar 2008 19:09
1996 1.9td estate extremely poor fuel economy - mjm
Whisky, you are quite right. I've just had a look in the handbook and 65 litres is listed for all the models in it.
Even if the figures are "nominal" I wonder if the OP can really get 68 in it.

It looks as if I was driving with kid gloves on my feet for nothing, then :)
Reply | Report as offensive | Link
Wed 19 Mar 2008 19:28
1996 1.9td estate extremely poor fuel economy - alfacossie
Hi everyone thank you for your replies.

i will reply to all your replies in one go.

Firstly the car doesnt smoke. it does if driven hard at high rpm but its normal. there is no oil under the car at all.

The car starts perfectly and as to weather it pulls or not thats a matter of opinion, but it just out does my brothers 1.25 zetec fiesta so i guess its ok.

Now the brakes, yes on occasion my front brake does stick on but i wouldnt have thought this would cause the kind of deficit we are talking about only becasue i have had this previously with another car and it did effect the consumption but not by a gerat deal. so i will sort the brakes at the weekend and see if theat helps.

I also suspect the car is running as if the engine is cold as the idle is always 1075 rpm hot or cold and the engine never gets over 65 degrees, i will replace the thermostat but will that make the car think its now running hot so not as rich?

I will change the fuel filter to but if this qwas old it would surely just be blocked and more economical?

Also as for the 68 litres, it cost me exactly £80 to fill the car which worked out 68.7 litres which is what the reciept says. I always run the car untill the fuel needle rests on the stop at the bottom or just 1-2mm above it and i fill it up untill i can see the diesel in the filler neck and it stops lowering as air is released and this generally does me about 66-68 litres each time which i would suggest is normal.

thanks again for your replies and any more help would be greatly appreciated.

Paul
Reply | Report as offensive | Link
Wed 19 Mar 2008 21:26
1996 1.9td estate extremely poor fuel economy - Screwloose
Paul

The fast idle would have been worth mentioning at the outset. Maybe the coolant temp sensor is faulty? It should make it smoke - but....?

What is the engine code on this one? Should be in the middle of the VIN; D8B or DH...X, Y, or Z.
Reply | Report as offensive | Link
Wed 19 Mar 2008 23:48
1996 1.9td estate extremely poor fuel economy - alfacossie
Yeah i know but i only realised this today hence why i thought i would add it to the equasion.

non of those codes are in the vin although it starts VF7X and the engine is CUJ does that help at all?

as for the temp sensor, this is a possability however its reliably cold when driving and if you just leave it running on the drive it always gets up to temperature eventually and the fans come on as they should so i suspect the temp sensor to be ok?

Thanks again

paul
Reply | Report as offensive | Link
Thu 20 Mar 2008 00:19
1996 1.9td estate extremely poor fuel economy - Screwloose
paul

If it's running at 65 instead of 85, that isn't going to make as significant an effect on the fuelling as if the ECU thinks that it's -40C.

Have a look on the engine plate for the engine code - it's not CUJ.

Sort the brakes first - they can make a huge difference.
Reply | Report as offensive | Link
Thu 20 Mar 2008 07:47
1996 1.9td estate extremely poor fuel economy - RichardW
It's 1996 Screwloose, odds on it's a purely mechanical set up. Sounds like a new stat is required, but this shouldn't make much difference to the economy (a diesel is not like a petrol in that respect). My 1.9TD hatches never got much over 40 driven reasonably, so I would expcet 37/38 from an estate - the brakes dragging could easily bring this down to the where the OP is. The rears are the most likely candidate - probably find the calipers have twisted round and are touching the discs....
Reply | Report as offensive | Link
Thu 20 Mar 2008 10:25
1996 1.9td estate extremely poor fuel economy - oldnotbold
The Xantia and the 405 are the same girl in different frocks, apart from the suspension set-up. My 405 TD estate does about 40-42 on short Dad's taxi runs, and around 44 keeping at 75 indicated on a longer run, so anything less than 35 needs to be looked at, unless you are going everywhere in 2nd/3rd.

The temp should be 75-80, but there's always the chance that the dial is wrong, not the stat. Old fuel filters do have an adverse effect on economy, but don't ask me to explain the physics!

Edited by oldnotbold on 20/03/2008 at 10:27

Reply | Report as offensive | Link
Fri 21 Mar 2008 14:20
1996 1.9td estate extremely poor fuel economy - Peter.N.
I would be inclined to change the thermostat anyway, 65C is considerably below what it should be and must be a contributary factor. Make sure you bleed it properly afterwards!

Edited by Peter.N. on 21/03/2008 at 14:21

Reply | Report as offensive | Link
Sun 20 Apr 2008 11:05
1996 1.9td estate extremely poor fuel economy - Billone
Guys, can you please tell me if there are fuel filters in the fuel tank of my 1996 Xantia 1.9 td estate?

Or is there a filter in the pump itself?

Once the revs go over 3000 or 80ish MPH she starts to surge....miss...as though she aint getting enough fuel.

I changed the fuel filter (again) yesterday but the problem's still there!
Reply | Report as offensive | Link
Sun 20 Apr 2008 20:51
1996 1.9td estate extremely poor fuel economy - *Gongfarmer*
The fuel filter on my 97 1.9 TD was a big black plastic cannister up on the front of the engine. Two or three allen headed bolts held the top on. Changing the element was all of 5 minutes work including draining the water trap at the bottom of the unit.
Reply | Report as offensive | Link
Mon 21 Apr 2008 20:12
1996 1.9td estate extremely poor fuel economy - Billone
4 allen bolts actually.......

The filter element is clean and without water in the bowl.

The problem only arises in 4th and 5th gear at around 3500 rpm.

It's driving me nuts!!!
Reply | Report as offensive | Link
Tue 22 Apr 2008 00:28
1996 1.9td estate extremely poor fuel economy - dave hy
hi i had the very same problem with both of the xantia's i had. they have a fine gauze on the bottom of the fuel pick up hose witch is part of the fuel sender unit. You can get to it by lifting up the back seat and lifting off the black rubber cover and unscrewing the large black plastic nut that screws it in to the tank, but be warned they usually break so you might have buy a new plastic nut. The gauze is on the bottom of the fuel gauge sender unit and can get very blocked. The problems i had was lack of power especially when in cruising speed. Bad starting when warm because of vacuum building up in the fuel pipe. I hope this helps you and this is the cause as it drove me mad for 8 months with my first xantia diesel turbo.
Reply | Report as offensive | Link