I've got a manual 115cdti zt with synergy2 and replaced MAF sensor and I also get around mid thirties mpg mixed driving!

Having read a few threads I've decided to try replacing the PCV valve...and EGR clean will be done soon. I'm hoping that will improve the MPG a bit!?!?!?!

Any other suggestions would be welcome tho!

 

I have cleaned out the EGR valve when i got the car at 63k miles (now done 80) but i've not replaced the PCV.

 

Air intake mod?

http://forums.mg-rover.org/showthread.php?t=214388

 

I get mid 30's from my manual CDTi with synergy2 fitted, it is very smokey though so overfueling a bit.

 

Or under airing

 

my mpg must be pretty normal then.

Teadrinker you must have an extremely light foot!!

 

Not especially ! I prefer to think I drive carefully and always planning ahead.

A bit of background info on my car, its an 03 auto tourer, had 92,000 miles when I bought it end of last March, now almost 104,000.

The previous owner had used it mainly on motorways and it has been serviced as per the recommended intervals.

I have had an interim oil and filter change done, now due another oil change ( I prefer to do them about every 6000 miles).

I also fitted a new air filter and fuel filter when I fitted the Synergy unit, (setting 10) apart from that the car is standard, no other mods to air intakes or anything. I did take apart the egr valve to check but found it to be fine.

For a while I was running on "home made bio" (recycled veggie oil) without any problem, in fact seemd to prefer it! I did try adding Millers additive for a while but dont bother now.

My main journey is about 80 miles which consists of about 2 miles steep down hill , then a mile on B roads before joining an A road dual carriageway.
Approx 10 miles to the first roundabout, then 2 more roundabouts within the 4 miles or so. After that, its dual cway for over 40 miles, no stops.

Two junctions with traffic lights then 15 miles motorway, finishing with the last 5 miles through city traffic, slightly uphill to finish. Then return!

So, the majority of the journey is steady cruising, usually about 60 - 65mph unless I am in a hurry. I have tried it at 55 mph but was fed up being overtaken / chased by big wagons!

The start of the journey is downhill and I dont rev the engine until its warmed up. I try not to brake when approaching junctions, I plan ahead and slow down if needed but maintain momentum through roundabouts whenever possible. I tend to keep the revs below 2000 rpm and ease off the throttle until the next gear kicks in.

I also disengage cruise control when going uphill and maintain revs myself, speed might drop slightly but saves the revs rising.

I have measured fuel consumption a few times "brim to brim" and found the computer to be slightly optimistic, but even allowing for 10% error, as stated originally 45-50mpg is normal without trying (50-55mpg on computer).

For comparison, my other car is a Jag Sovereign 4.0 litre, doing the same journey will return about 22-25mpg, dropping dramatically around town and up the hills!

I used to put £30 of fuel in the Jag for each return journey, I now put £30 diesel into the 75 and get 2 return trips and a bit more.

I suppose its fair to say that my car has spent most of its life cruising on motorways and is now "run in", probably much better than stop start around town. I dont consider the fuel consumption to be abnormal, pretty much what I had hoped for!

 

Wonder what the normal running temperature is? I'm running around the forum shouting 'too low, too low' whenever a question about diesel economy comes up. From what I'm reading, most diesels are running too cool to get best economy. You need to be seeing 90-95 Degrees C. I'm sure that applies whatever bells and whistles are fitted.

I'm not jokin'!

 

Wonder what the normal running temperature is? I'm running around the forum shouting 'too low, too low' whenever a question about diesel economy comes up. From what I'm reading, most diesels are running too cool to get best economy. You need to be seeing 90-95 Degrees C. I'm sure that applies whatever bells and whistles are fitted.

I'm not jokin'!

Mine only goes above 85 degrees in traffic.

 

I'd be wary of MPG claims form some people. Some of the figures quoted are not only suspect, they are downright impossible under normal driving conditions. I get 34 MPG with a mix of "A" roads and town, mostly town. On a recent trip from Aberdeen to Woking in Surrey, I averaged 45 MPG. I think some of these guys put the car on a rolling road at a steady 40 MPH on cruise, then publish the figures.
I maen, a one and a half ton car doing over 50 MPG with normal driving? Come on, we didn't arrive from mars yesterday.

 

I maen, a one and a half ton car doing over 50 MPG with normal driving? Come on, we didn't arrive from mars yesterday.

If your "normal driving" is 400 miles of motorway I think that's quite possible.

 

I got 50mpg, only once I'll admit, on a round trip to Manchester. 400 miles, left at the right times to get roads as clear as possible, never went over an indicated 70mph which is a true speed of 65 in mine. Won't do it again as it drove me nuts but I wanted to see if I could do it.

 

Mpg

I too have a CDT auto, with a Synergy 1 set on 5. I do a regular run down the A2 and, on the round trip of about fifty miles I always got just over 50 mpg indicated. When I compared that with a brim to brim check the MPG were within 1 mpg. I never saw any smoke and never had to wipe black soot from the rear bumper.
(Doesn't apply at the moment due to a problem).
Do you see smoke? because if you have a new Maf you may be overfuelling if you have your Synergy 2 maf compensator set too high?

 

I have the maf compensator on low

with the synergy 2

High power = 3, 6, 9 and 10(very high)
mid power = 2, 5, 8
low power = 1, 4, 7

with

High maf = 7,8,9
mid Maf = 4,5,6
Low Maf = 1,2,3,10

So I am running high power and low maf.
I could try turning the Maf compensation off and see what happens I suppose.

I dont get soot on bumper due to shape of pipes thankfully. But If i rev when stationary I mark the road!

 

Well, what I'd give to be getting 34 whole miles a gallon locally from my '51 (120k) 'new (to me) CDT Tourer!! Today my consumption readout was 24.3mpg- over a 135-mile distance, BUT at an average speed of 16.7mph! Methinks there may be a connection! No, I don't have a lead right foot; yes, I do try to use the overrun fuel-cutoff facility, and occasional coasting! But after reading and learning from these pages, I've even tried 'keeping it on the turbo' during acceleration. And this from a guy who just disposed of an old xj40/xj6 Jag Auto- and regularly got 4mpg better than his friends in similar cars! Three thoughts:- ONE: though my Tourer's in beautiful condition, with an immaculate service history, I'm guessing nobody's ever thought of checking/servicing/replacing the MAF/PCV/EGR's- and possibly the thermostat, too! I will be, however! TWO: My FBH's packed in- and with recent frigidity, this does NOTHING for warm up! THREE: I've been mainly running to and from my daughter's during the cold snap; fairly traffic-free- but only 2 miles one-way!! Anybody still surprised- or even got WORSE suggestions/consumption to confess??!!

 

The problems with Diesels is that without a FBH you get crap MPG in the cold and with one... oh, you get crap MPG in the cold due to the extra fuel burnt :lol:

 

FBH uses very little fuel in reality and gets the coolant heated quicker.

 

i have to admit that my CDTi vary rearly gets to warm up fully as i only tend to be going to the supermarket or to uni (all less than 2 miles away). The odd motorway trip does seem to get reasonable mpg but my average is still pretty bad.

I'm starting to worry that the oil never really gets to warm up properly and I may be damaging the engine. Takes so bloody long to warm up though!!!

 

Been thinking a bit more about fuel consumption and reading a few old posts, its obvious that consumption can vary by a large amount dedpending upon the use and style of driving.

As I have said, 80-90% of my 75 driving is steady speed mway / dual carriageway, i.e. perfect conditions for economy, so to be fair, may not be truly representative of "average / normal "driving.

A friend with a Volvo S70 diesel was recently complaining that he only manages mid 30s mpg, but most of his driving is around town, short journeys, possibly more like the average driver.

To put it into perspective, another person I know told me recently that their Renault Megane did 35mpg on a trip to Scotland and seemed happy with that!

Give me my 75 anyday for all the extra comfort and style!

Would it be fair to say that 50+ mpg is likely on a steady run at sensible speeds, but figures will drop to mid 30s if you spend most of our time in town driving ?

 

I think the "combined" Rover 75 figure was 48 MPG
The phrase that springs to mind is, :- You're 'avin a laugh!

 

I love that you're getting crap fuel economy, it just makes me feel so much better about my 47mpg average

 

i have a 2002 rover 75 cdt with a sinergy2 set on 3 and the other switch on ( lost the papers from ron, cant remember if it have to bo on or off!) i have a very heavy foot and the average speed on my 20 miles daily trip to work is 99 mph! my car dont tell the mpg but i belive is not over 30! i drive to romania every year and with a full tank going at 110mphonly on motorway i get around 380-400 miles! it is good or bad i dont know and i still drive the same every day and i have to admit some times i cant belive i have to fill the tank again so soon! i will say.. this is life! by the way when i put my foot down i cant see nothing in the back only a huge cloud of smoke! regards viorel

 

I'm getting 35 mpg at the moment thats for nearly all short journeys, i.e. 6 miles each way to work + a few start stop trips in the day. Once the weather warms up that figure usually increases to 39-40 , if I throw a few longer runs(150 miles+) then it goes up to 46 ish.

Last year we had a couple of weeks in Cornwall and I averaged just short of 50mpg , the best I ever saw was 55mpg on a very steady run to Scarborough and back for a family day out.I get between 450 and 550 mile from a tankful depending on the time of year (presumably down to ambient temperatures)

All I've done to the car is the air intake mod and cleaned the EGR out , it's a 2001 cdt with 97K on the clock and very probably needs a new maf but I'll replace it when funds allow me to buy a synergy and pierburgh.

 

hi all

i have an zt auto 2.0 diesel and now get between 38.7 -39.2 mpg no more i take it easy at 70mph , as the zt is the best motor in the world .

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I should have know I'd start another deluge with a thread like this - I though it had all been done before!!

Seems there's a lot of variety in there. Firstly the manual gearbox people above need to declare themselves - there's a big difference between what you'll get and us autos - auto box + heavy car = mucho fuel.

But the variety is predictably down to how you drive and where you drive. My own weekly commute is mostly town with about 10 miles of A-road, which includes a steep hill and several roundabouts. Seems my 34mpg is about right.

Which as I said in my other thread, makes a 27mpg petrol engined car (Omega, S80, 5-series) pretty tempting.

 

tell you what grandtourer , my manual gave 60mph at 2k revs in fifth , the auto gave 70mph at 2k revs coming up the motorway [that surprised me not having driven an auto] flyer:eyes:

 

I have a manual cdt and my trip is 18 miles into london at rush hour, stop start most of the way ,i've not done a brim to brim calculation but the computer tells me 24 to 27 depending on my mood! on the odd occasions that i have been on motorway i normally cruise at 65 to 70 ( to many points to go faster )and on the level get 50 to 55 but this normally drops to high 40's on the incline

 

i had the yellow fuel light when i took delivery of the 75 auto today , so after i have emptied my wallet filling it i will do a milo test and post back , still to clean egr , do air mod etc etc etc so i will do a before and after . flyer.:run!: oh and will service the monster at weekend [ah its first service from me ]

 

I'll await the result eagerly. Seems like the near 50 MPG guys are well in the minority, so your trial run should be very interesting. Normal driving remember, no coasting down hills.

 

maybe the gearing is set up to try and compensate for the aditional fuel used by the auto.

 

whole new learning curve for flyer , Flyer.:slap:

 

you gone idle have then flyer , you`ll be telling us it has cruise next

 

you gone idle have then flyer , you`ll be telling us it has cruise next

never mind that , i am also drinking TIGER , £2 for 4 at morrisons , yahoo . flyer [hic]:=p:

 

Just for the record it is possible to obtain an average mileage of around 50 mpg from the diesel. It does rely on driving sensibly and at reduced speed and so is not for everyone.
I drive a 2003 75 cdt Tourer round the West of Scotlands Motorways and A roads doing up to 18,000 miles a year in the course of travelling for my work.
"Normal" motorway or A class road speed 50-56mph on the cruise control. (apologies if you come across me on the M77, M8 or A737)
On "30" roads with light traffic and reasonably long stretches cruise set to 35 actual speed 30/31.
Harsh acceleration and braking avoided by reading road ahead and lifting foot well in advance of junctions, lights, roundabouts etc
If I get caught in traffic (I avoid rush hours if at all possible) I will get 49/50mpg. If I have a good week (tank filled brim to brim every 7/8 days) I will get 52/53mpg. Best result 54.9 mpg, worst 42 mpg.
This all started when fuel prices soared last year, being me I have become addicted to trying to better my best result despite fuel dropping down below £1.00 litre.
As I say this type of driving style won't suit all but there are some comments made in previous posts which I felt required a balanced response.
Just as a footnote I had a Montego 2.0 Turbo Diesel estate for 5 years and without trying would average 51-53mpg. The car was easily 350Kg lighter so I can only imagine what it would have done if I tried. Miss the car but it was a pile of junk compared to the 75.