Xantia Fuel Gauge

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Chrispy
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Xantia Fuel Gauge

Post by Chrispy »

Hi all,
I've just bought my first Citroen after getting rid of a BMW 320i cos it was far too thirsty.
Anyway, I'm worried that my new Xantia TD (99 T reg) is using far too much fuel. Either that or the fuel gauge is lying completely.
I put in 22 litres of juice from almost empty, which made it read 1/2 a tank. It then dropped quite quickly to about 3/8's of a tank. Now, after doing 120 miles the gauge is reading on the red again.
I can't see a fuel leak anywhere so I'm wondering if it's my gauge?
It does seem to fluctuate a lot when going round corners and up and down hills etc. Also, my idle does seem too high when the engine has warmed up, staying at 1000rpm all the time.
Any help is much appreciated.
Thanks,
Chris.
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fastandfurryous
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Post by fastandfurryous »

Almost all fuel gauges are somewhat non-linear. The only way to be sure of your fuel consumption is to brim the tank and zero the trip-meter. When you next come to fill the tank, brim it again, noting the litres needed to fill and the mileage on the trip meter. You can then get a reasonably accurate guide as to your consumption. 40MPG would be lowish, 45 acceptable and 50 not bad at all.
As to your idle speed, this is adjusted by a small screw and locknut on the back-left of your injection pump (if it is a bosch). There is a small lever which has an upper and a lower stop. the upper stop is the fast (cold) idle speed, the lower stop is the normal (hot) idle speed.
If your fuel consumption is excessive, check for binding brakes before condemning the engine.
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Post by RichardW »

Xantia TD will only average about 40 - unless you drive it very gently. Only way you can judge consumption is to either brim it as suggested, or keep a log.
1000 rpm idle is too high, but a 99 will have the vacuum operated fast idle rather than the wax-stat - which should pull it to fast idle when you switch the air-con on. So with the air con off and the engine up to temperature, re-check the idle speed. If it's not dropped back to 800 or so, and climbs to 1000 when the air con is switched on, there's probably a fault with the electrovalve. Note that if you have the heater direction slider on demist, the A/C may engage without the switch being on...
Chrispy
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Post by Chrispy »

Well, I've just been to the petrol station and filled it up. It took 53 litres to fill. Basically according to my calulations I've used about 16 litres over 123 miles. That's 34mpg!!! Yikes!! What am I doing wrong? I'm not exactly caning the thing... There are no puddles of fuel under the car after pulling away either and I can't smell it. It's wierd because according to the silly fuel gauge I did 30 miles using 1/4 of a tank this morning (it dropped really fast).
It's long overdue a service so it's booked in for one next week (air filter, oil and filter, cam belt etc) so we'll see after then.
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Post by Kowalski »

My Xantia TD is averaging 47mpg, and it is not driven gently. Driven gently I've topped 50mpg over a couple of tanks.
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Post by Rostami »

The best way to find out what is going on is to fill the tank up, write down the km reading or reset it, drive for as long as possible and when the gauge goes to the red then fill her up again. Knowing how many km you did between fill-ups and how much you needed to do the second refill, its quite easy to determine the fuel consumption.
Please note that some brands of diesel may be more efficient than others on your engine and also that not all gas stations are as percise as we would expect (In portugal that is the case).
So if you conclude that mileage is in fact high, I sould suggest that you check a few basics:
- Wheel bearings: they give up easier than most people think. The extra friction leads to higher consumptions.
- how does the exaust smoke look like? if its sooty then you know that the diesel is not being burnt.
- air filter: is it new? Air inlet tubes ok? Intercooler?
- Injector pump: You need to know if the advance mechanism is OK. Also, you should maybe check how much diesel is getting pumped.
There are many factors that can contribute to a high mileage.
On my xantia the fuel gauge has some kind of memory effect making it highly non-linear. After a period of driving around in the city with high consupmtion figures, the gauge goes in to the red bu then on the next day if I go driving around on the freeway tthe gauge needle rises andeasily reaches 1/4...
Good luck!
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Post by fastandfurryous »

Having just come from a petrol vehicle, are you sure you have the correct driving technique for a TD engine? You should never really have to take it over 3000RPM, but don't be afraid to floor the accelerator at low revs. If you are habitually taking the engine to 4000RPM even at only partial load, then there's no way you'll ever get any economy out of the car. That said, even if I drive my 405 to within an inch of it's life, and redline it in every gear, I can't get the economy to drop much below about 37-38ish MPG.
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Post by Chrispy »

I have owned diesels before so I'm fairly familiar with how to drive them and the economy to expect. I had a 405 GLX 1.9TD a few years back, and also a 306 HDi 90 DTurbo as a company car last year. Both were very good, especially the 306 (that went like hell!). My petrol annoyed me becuase of the lack of low down torque...you had to thrash the thing in order to make it go. I like diesels because you don't.
The economy of this thing may be closer to 39mpg after a few more calculations but, to be honest I'd expect to be better considering I spend most of my time on the M1. It's way overdue a service (16,000 miles overdue to be exact) as I've just bought it, so I'm hoping this will help. It only has 64k on the clock too so I doubt that anything is seriously broken. I've had the air con on too a fair bit so I'm assuming that may make it worse? I spoke to the local Citroen dealer earleir and asked them....surprise surprise they were no help whatsoever. The guy on the end of the phone didn't sound like he's ever been near a car in his life. Sigh...
I'm hoping to get it taken in for a tune pretty soon. 90bhp just ain't enough after having 150bhp to play with even with all the torque, so I'm hoping 110bhp will help.
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Post by ActivaV6uk »

get that car serviced, it should make a massive diference!
Andy
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Post by MikeO »

Your air con will definitely increase your fuel consumption - try leaving it off - it's hardly been necessary recently, has it? [;)] A new air filter will probably work wonders...
Mike
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Post by np »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by ActivaV6uk</i>

get that car serviced, it should make a massive diference!
Andy
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
I also find when mine needs a service that it can lose about 5 mpg overall.I filled mine up the other week,60 ltrs.Ran it till it ran out of fuel(on the M4).The fuel light was on for 180 miles(comes on when there`s 7 ltrs left,yeah right!).Working it out i did 44 mpg,with quite a bit of hard driving,a/c on sometimes aswell.
I do find my fuel gauge is erratic.[:)]
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