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
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.
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.
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).
1) The tyres are at the correct pressure. -and-
2) The brakes are not binding -and-
3) Assuming that it has no particulate filter and it's not smoking -and-
4) The engine management light isn't on -and-
5) There is no major loss of torque -and-
6) You're not towing a barn or driving @90mph 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 Midgley ( snipped-for-privacy@maps.maps.chrismi-maps.co.uk.maps) gurgled happily, sounding much like they were saying :
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...
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!
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.