Fuel consumption. xantia

someplace-else · Post by **someplace-else** » 06 Feb 2003, 06:41

I have recently bought a xantia td est with 125k recorded, having run a bx rd est to 200k with few real probs. however I now find that even though the bx is still returning 45-50mpg.... the xantia is is at times returning less than 30mpg...! something I was not expecting.
On starting there is a little smoke from the exhaust, with the associated lumpiness, but that lasts only 15 sec's or so.... then all is fine. Glow plugs have been changed. service history is comprehensive to 80k or thereabouts, however the car does feel slightly slugish at low revs... till the turbo kicks in, no smoke etc.
It did cross my mind that it may be injectors.... possibly aged and delivering too much fuel...?
Any idea's...?

tomsheppard · Post by **tomsheppard** » 06 Feb 2003, 14:31

Well, possibly but rich engines usually pump black smoke. My guess is that either A:you haven't done enough miles yet to get to know the fuel gauge which is rather pessimistic. (Brim the tank, drive 200 miles and brim it again. Work it out from that.)
B: you have a dodgy leak off pipe. This would explain the lumpiness on startup (Air in the system) and any leak here would do your consumption no end of no good. I suppose you have checked the air filter so I'll plump for B. Look for a fuel leak at the top of the engine. The xantia is a good bit heavier than a BX which is actually little more than a Citroen badge supporting a hologram so It suffers from weight and the consumption is greater. The blower causes it to drink more- lots more if you boot it.
Edited by - tomsheppard on 06 Feb 2003 09:36:55

rory_perrett · Post by **rory_perrett** » 06 Feb 2003, 14:51

I too was a bit shocked at the difference in the fuel consumption between my bx 1.7 turbo diesel estate and the 1.9 turbo diesel Xantia we bought last year. BX has done 250k on the original injectors and returns an average of 48mpg.
The Xantia hatch 106k miles averages nearer 38 mpg although true comparison is difficult as the cars have different useage patterns.
My observations are:
The Xantia is a significantly bigger and heavier car.
The variation in fuel consumption due to different conditions appears greater for the Xantia than the BX. On a 70ish mph motorway run Xantia manages about around 87% of BX figure (46/53) around town (probably mostly due to extra weight) its nearer 71% (32/45)
The summer winter variation on the Xantia seems greater suggesting the Xantia takes longer to warm up and/or is less efficient while warming up. This may also explain some of the lower "around town" mpg as they tend to be the shorter trips.
Compared with the BX the Xantia feels slow so the temptation is to be heavier with the right foot, keep in lower gears longer, use higher revs thus using the turbo for a greater proportion of the time.
Having said all that sub 30 mpg does seem low unless its all short town trips in cold weather.
Rory

jeremy · Post by **jeremy** » 06 Feb 2003, 15:55

A silly suggestion - have you a fuel leak from the tank plumbing? - have a look underneath after you have filled the tank and see if its dry! The reason I suggest it is I had an obscure vent pipe split on a ZX if similar age.
next suggestion is if everything else is ok - check the timing of the injection pump. If its too far advanced the engine chatter will be noisier than usual and retarded it will be quiet.
At your mileage the injectors are suspect. I had mine on my TD overhauled about 18 months ago and the difference was remarkable - excellent starting, no need for heat when warm, minimal heat from cold, noticeable fast idle phase, more performance and a bit better economy. They had got to the stage where cleaner didn't make much if any difference and apparently the smoke was objectionable if the vehicle was started in a confined space. The improvement was so great the head gasket blew after 18 miles!
Jeremy

someplace-else · Post by **someplace-else** » 06 Feb 2003, 16:46

Thanks for the above replies....
It looks as though the problem might be me...!
The journeys regularly covered are a mixture of the normal school run... not every day though.... and trips to work on open roads.. 60-70mph.. around 15 miles each way.
Looks like I will have to ease off a bit...!
I've already checked the leak off pipes.. there are no leaks evident .. however they are hard and appear brittle.. ?
Fuel pipes , and the car in general show no signs of any leakage either (That I can see).
Air filter and the inlet ducting all are OK.
Re the injectors... and summising that they have not been serviced etc..... is it realistic to expect significant difference if that were so...?

tomsheppard · Post by **tomsheppard** » 06 Feb 2003, 17:32

I doubt if you would see any measurable improvement with recon injectors. Even at Andyspares prices, that is nigh on £150. That is a lot of diesel if you are only going to get a couple more mpg. Do all the other things first. New air cleaner. Check tyre pressures. Take the 1/4 ton toolbox out of the boot. Check the cold start regulator.
Check the thermostat is the right one. Jack it up and see if the wheels all spin freely.

Gavin1 · Post by **Gavin1** » 06 Feb 2003, 18:13

I've had a similar experience from TZD Turbo to Xantia TD and had the same shock with the fuel consumption. The Xantia is heavier and is lower geared than the BX, it undoubtedly makes a better tow car as a result of the low gearing but the fuel consumption suffers. I used to get high 30s - 40 mpg from the Xantia and 45+ from the bx.
Funny thing is I didn't get around to selling the bx, it just sat on the drive with a broken fuel pump. I've fixed the Bx now and as its faster and more economical than the Xantia and as I no need to tow now it will be one I'll keep!