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Old 14th April 2019, 23:58   #1
roy 1953
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Hi again,
had my rover diesel connoiseur se now for a week and love it. checked plenum drains all dry and clear. drivers door card was loose, now re-fitted with new clips, rear nearside footwell found to be wet, on removing rear seat found two large puddles of water under there and wet foam insulation, checked sunroof drains and found three leaking into car, these fixed.
Nothing on engine has yet been checked except levels, had a run today on motorway and found fuel consumption to be high at 33 mpg on computer.
Temp gauge never went up over the 7 o clock mark, will this affect fuel consumption?, [ I have ordered an inline thermostat ].
Roy
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Old 15th April 2019, 00:10   #2
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My CDT manual has the standard stat, the gauge rises to 9 o'clock after a couple of miles, and stays there, whatever the conditions. Over the 16 months and 28,000 miles I've had it, it has averaged 45mpg, and I know others average closer to 50mpg. I take it that the brakes aren't binding, and that the oil, fuel and air filters have been changed? Might be worth booking one of the forum mechanics on here to give it the once-over, and connect it to T4 diagnostics.
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Old 15th April 2019, 01:43   #3
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Forget the 'computer' until you do a brim to brim fill. It is notoriously inaccurate. My own one reads 10% low.

Similarly the temp gauge is only a guide, however 7oclock is too low. 9 o'clock position is anywhere between 75 and 105. Use the obd display. (Search for 'wip' in the search facility, and that will bring up the how to).

The stat will affect the mpg negatively, and it does read like yours is faulty, however do not panic regarding mpg until you get the brim to brim. If you find your mpg display is inaccurate, then it can be adjusted using the how to mentioned above.

Incidentally mine is an auto, which displays 33 to 36mpg, allowing for the 10 % lower, for my commute it is about right. 10 miles from cold with mix driving. The autos on our cars are roughly 10mpg less than the manuals. (Last longish run I had, the car did about 45 mpg)

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Old 15th April 2019, 08:22   #4
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The cool running engine will drop your mpg by a few miles each gallon, once the stat is fitted you should see an improvement.
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Old 15th April 2019, 11:36   #5
roy 1953
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The brakes are not binding and the filters and oil have not been changed yet, service due next month according to the service history.
Once I receive and fit the inline thermostat I will do a brim to brim and a correction in the computer as stated.
Also mot due in a month so will carry on from there.
Thanks everyone
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Old 15th April 2019, 21:21   #6
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Quote:
Originally Posted by roy 1953 View Post
The brakes are not binding and the filters and oil have not been changed yet, service due next month according to the service history.
Once I receive and fit the inline thermostat I will do a brim to brim and a correction in the computer as stated.
Also mot due in a month so will carry on from there.
Thanks everyone
Roy

Also worth getting the MAF and MAP sensors checked to be sure they are in spec. If your inlet manifold is gunked up, chances are the MAP sensor will be too. I cleaned mine when I bypassed the EGR. Check the PCV too. A bit of Miller's Ecomax diesel has helped the car run a bit more economically too.

That said, my ZTT CDTi manual only seems to do 42 combined, and I've developed a pretty light foot. Even on long manly motorway journeys I can't improve it, and the mpg is best when I do 50mph ish, so A roads are a blessing! If you find a magic bullet to improve mpg any further I'll definitely be interested!
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Old 15th April 2019, 21:34   #7
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Not really relevant to you but my petrol does about 31 on my normal commute during the summer and about 29 during the winter. Getting the engine up to temperature is key and on a run, when the engine is hot for most of the journey its running 35+mpg
I'd start with the thermostat.
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Old 15th April 2019, 21:48   #8
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I got 16 mpg out of my V8 ZTT yesterday....................
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Old 15th April 2019, 22:27   #9
roy 1953
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How do I get the map and maf sensors checked?, and where are they?, is it a check for cleanliness or an electrical check, can I just blank off the egr valve as I have done on my ford transit mk 7 without any ill effects or will I need the by-pass pipe I have seen for sale. I am new to these engines and don't know the layout yet, haven't even taken the engine cover off until I receive the thermostat.
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Old 17th April 2019, 20:32   #10
roy 1953
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Received and fitted the in line thermostat, now the temp gauge is at 8 oclock
and 84 degrees.
Will see if this makes a difference to the mpg, found the info on maf and map sensors in how to section.
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