Xsara HDi 110 fuel consumption

nick · Unread post by **nick** » 06 Sep 2006, 18:13

Hi everyone,
I've just recently bought a Xsara HDi to replace the Xantia TD Ive had for the past 6 years. Generally I'm very pleased with the Xsara so far, but the only problem is the fuel consumption. I expected a Xsara HDi, considering its a slightly smaller, lighter car with a DI engine, to be noticeably more economical than the IDI Xantia 1.9TD, but so far there doesn't seem to be that much difference between them

Eg;
Around town: Xantia 39-41 mpg, Xsara 40 mpg
Mixed: Xantia 43-45 mpg, Xsara 47 mpg
Constant-ish 65-70mph: Xantia 48-51mpg, Xsara 50mpg
Thrashed!: Xantia 39 mpg, Xsara 39 mpg

Perhaps I'm not comparing like with like - the Xantia figures are measured from fill-up to fill-up, the Xsara's are from its onboard fuel computer which may or may not be accurate. To be fair, the Xantia figures do also seem better than many normally get from a 1.9TD.

Today I've replaced the air filter on the Xsara, though the one I took out wasn't especially dirty, and put some "Diesel Magic" in the fuel to see if that improves matters. The man I bought the Xsara off reckoned he never usually got much more than 40 mpg.

So do I have a particularly economical Xantia 1.9TD, or a not very economical Xsara HDi here ?!

bencowell · Unread post by **bencowell** » 06 Sep 2006, 22:07

Sounds like it needs a trip to an independent.

My C5 HDI gets 45mpg most of the time, even with quite a lot of urban.

Also, the computers lie!

AndersDK · Unread post by **AndersDK** » 06 Sep 2006, 23:32

The 19TD is a very economical engine - one of the best IDI diesels ever made in that aspect.
Still it only produces a fraction under 90Bhp.

Your HDI 110 produces 110Bhp (hence the designation). You wont get the extra 20Bhp for free - even with a DI diesel.

I'd say you get good mileage for your fuel money - nothing to worry about.
Note that you may think you are VERY lightfooted on your right - but still there are many drivers even more lightfooted than you are

Mileage is more the result of drive style - than technical issues - believe me

Unread post by **Peter.N.** » 06 Sep 2006, 23:33

Unfortunatly modern common rail engines rely primarily on the computer to control the engine, so the economy is not so 'under your control' as it is with the old mechanically controlled pumps. A modern engine can appear to be running OK but you dont really know without checking the information that the computer is sending to the injectors and only your dealer can do this. Thats one reason that I am hanging on to my XM as long as possible!

nick · Unread post by **nick** » 07 Sep 2006, 09:07

Thanks for the advice chaps, hopefully I was panicking unnecessarily - I've just filled it up & calculated from the actual mileage. Its come out at 52, whereas computer says 42

I haven't been able to fill up at the same pump twice yet, so this may still not be very accurate, but I hope its just a case of the computer lying.

nick · Unread post by **nick** » 21 Sep 2006, 21:12

Just a quick update, after a few more fill ups the average fuel consumption on shortish journeys around town is about 48-51 mpg, which is nice! The computer meanwhile says its averaging 36-37

The fuel computer fault I can live with, but what is more strange is the fuel gauge - it just keeps dropping. With each fill up it gets lower & lower and is now showing just under half full. Thats with a completely full tank!
I've heard this is a common fault with the Xsara, is there any known cure for this?

jeremy · Unread post by **jeremy** » 21 Sep 2006, 21:39

Yes - fit a ZX fuel level unit - mine reads empty and is flashing the light with about 3.5 gallons left! - measured by filling the tank - no computer to mislead!

nick · Unread post by **nick** » 21 Sep 2006, 21:51

Good idea! I think the fuel level sensor/gauge it currently has must have come from a V8 Range Rover.....

JohnD · Unread post by **JohnD** » 22 Sep 2006, 15:45

Within the last year I've changed from a Xantia 2.1 to a C5 estate. Using GPS on journeys such as Calais to Malaga, I realised the Xantia was reading 5% high on both mileage distance and speed. Therefore my average consumption was more like 40mpg rather than the 42 figure obtained by dividing miles covered by gallons used. The mileometer on the C5 is accurate compared with GPS and the fuel computer agrees almost spot on with miles divided by gallons.

nick · Unread post by **nick** » 22 Sep 2006, 16:32

JohnD wrote: The mileometer on the C5 is accurate compared with GPS and the fuel computer agrees almost spot on with miles divided by gallons.

My dad has also found the computer on his C5 HDi to be very accurate, Xsaras on the other hand seem to be way off the mark. A "friend of a friend" has an '01 Xsara almost identical to mine and says the mpg per the computer is usually at least 10 mpg lower than the real figure.

den169 · Unread post by **den169** » 22 Sep 2006, 16:48

Did 1800 miles to france and back last month and the c5 computer was spot on.

Homer · Unread post by **Homer** » 22 Sep 2006, 17:22

The computer in our 807 is spot on, I won't tell you what it does though, far too scary.

bencowell · Unread post by **bencowell** » 22 Sep 2006, 19:25

My C5 2.0 HDI 110 computer used to be 3 to 4 mpg lower all the time.

Since passing 60k miles, it has been spot on. Economy isn't improving though!