C5 mpg

Has anyone any ideas as to why my C5, 51reg, estate, only gets about 30-35mpg ? Average speeds & no clogging it. Its a high miler, 125k, but uses
no oil. I know it should do a lot more mpg than it does. Any ideas ? Cheers. Ray
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olddog ( snipped-for-privacy@newtrox.com) gurgled happily, sounding much like they were saying :

I'd say that was fairly impressive economy for a v6 C5.
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Adrian wrote:

I'd say its not bad for a 2litre HPi either! What type of engine is it, by the way?
SW
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Are you referring to Imperial gallons or US gallons? The Imperial gallons has a 1 pint more than a US gallon. So far my 1988 CXA 25 Prestige with automatic transmission has only been getting about 20 mpg highway, 15 mpg urban and that is US gallons at an average cost of $2.50 per gallon.

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Gene S. Park ( snipped-for-privacy@comcast.net) gurgled happily, sounding much like they were saying :

51-reg would suggest UK, therefore Imperial gallons. Besides, I doubt there's any C5s in the US.

$2.50 per gallon! You *poor* dear.
We're currently paying the equivalent of a bit over $6 per US gallon.
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Yikes! $6 bucks. Ouch!
However, what is the length of an average trip?
Here, in the Northwest, an average trip is minimum 170 to 500 miles. If we drive to San Francisco, we are looking at about 650 miles, all one way. It is 315 miles, one way to Vancouver, BC. So it can still be very expensive because of the large distances to travel. It would cost me about $90 for just gas on a round trip if I didn't buy gas in Canada which is more expensive. At the border I would probably have to pay $2.75 per gallon on the US side of the line.
I remember divining through France the summer of 1976 and gas was about $5 per gallon if I recollect. I remember that the distances between towns and cities was much shorter than what we experience in the western US.
Gene
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snip
1 US Gallon = 8 US pints = (8*16) = 128 fl oz [3.785412 litres]
1 Imperial Gallon = 8 Imperial pints = (8*20) = 160 fl oz [4.54609 litres]
so the difference is 0.760678 litres, ie 26.772138 Imperial fl oz or 25.721794 US fl oz
[ 1 US fl oz = 1.04085 Imp fl oz] [ 1 US fl oz = 29.57373 ml ] [1 Imp fl oz = 28.41305 ml ]
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Nah, It aint nowt special, it's just a bog standard ,110hp, 4 cylinder, manual box, diesel C5 HDI SX, 1997cc, Estate car. The same engine that my neighbour has in his Peugeot 407 estate, that returns 45+ mpg on a daily basis, just going 10miles round trip a day cross town, whereas i'm doing 45miles on a motorway each day & using the bog standard British gallon or liters. I dont think the MPG is impressive. Ray
wrote:

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Perhaps the engine needs attention? The injectors and cylinders may be in need of a good clean. (I get better than 45mpg with my ZX 1.9D, on a long run - and it doesn't do badly around town either).
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on the motorway -then-
My guess is that the mass air flow meter is broken and its reporting more air flowing into the engine than really is, that's causing the ECU to over compensate which inturn is over fuelling the injectors. However, check that there are no air intake pipes that have holes in them or are loose as that may effect air metering. The other possibility that comes to mind is that the EGR valve is stuck or incorrectly controlled. Both items are fairly common failures in all makes of modern cars.
Chris
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Chris Midgley ( snipped-for-privacy@maps.maps.chrismi-maps.co.uk.maps) gurgled happily, sounding much like they were saying :

<long list of perfectly valid points>
A 2.0HDi 110 C5 *ought* to produce similar figures to a 2.0HDi 110 407 - they're the same damn car, ffs. Same floorpan, same engine, same gearbox, same manufacturer - hell, they probably follow each other down the production line...
<silly question>
When was the air filter last changed?
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Have you carried out a consumption test "the old fashioned way" or are you relying on the on board computer? If the latter, I would suggest a brim to brim check before spending any money!
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Er, thats a point, i'm using the on board computer, I'll do a neck to neck test & get back to you all. Thanks for the input guys. Ray

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Any news yet olddog? I'm interested 'cause we've just got one and it's giving piss poor consumption on the 'puter. Doing a neck to neck at the moment.
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