very very bad mpg

[leet5r]

what can cause bad mpg appart from my driven , cheers

[t5_monkey]

there seems to be a few posts up about bag MPG at the moment - maybe the weather isn't helping?

[leet5r]

yeah .but does bad weather cause it to go to around the 15 mark in town

[Hallsy]

I wouldn't say 15mpg is very, very bad for town driving, unless it is mixed.

Mine is averaging 24.5mpg with relatively short journeys, but no town driving (stop/starting), and is an auto on 215k.

[LiamT4]

I know this might sound daft, but have you checked the tyre pressures, do you have your A/C on all the time, heated window/seats etc. But 15mpg around town don't seem to bad, mines prob around that mark in town, i'm getting 22.4mpg at the min, a mixture of driving.

[nobananas]

Ask a local garage to do an emissions test at various different constant rpm's and at idle. Might be that your Lambda sensors up the stick and causing it to over-fuel, an emissions test would show if there is any over-fueling issues.

[p fandango]

have you checked for any air leaks recently mate?

[siamblue]

My auto V70R AWD used to get 16 around town,

Gary

[cameron]

My HLM'd T5 is doin about 17.9 around town at the mo and its an auto :D

[p fandango]

and its an auto :D
you can't have everything mate :biggrin:

[Flatout Phil]

yeah .but does bad weather cause it to go to around the 15 mark in town

That sounds quite acceptable - nature of the beast. But when you consider that, as I followed a flat-out 350Z up a long motorway slip road today and there was absolutely nothing in it, it ain't a bad compromise on the pounds for poke. My R averages 15mpg, the T5 17.5mpg and the old 2.5 20v GLE about 20 I seem to recall.
These are motorway cars and as such, on a long level cruise at 55-60 I can get toward 40mpg. But not much fun.

[WOODY T5]

my mte'd t5 doing 23.4 around town its manual

[leet5r]

so i guess its about right then lol

[t5_monkey]

That sounds quite acceptable - nature of the beast. But when you consider that, as I followed a flat-out 350Z up a long motorway slip road today and there was absolutely nothing in it, it ain't a bad compromise on the pounds for poke. My R averages 15mpg, the T5 17.5mpg and the old 2.5 20v GLE about 20 I seem to recall.
These are motorway cars and as such, on a long level cruise at 55-60 I can get toward 40mpg. But not much fun.

350Z's don't seem that quick unless the driver is spanking the nuts off it - I had one try to overtake me coming out of a village 30 limit, he got alongside but then what can i say - epic Fail :) he ended up about 3 car lengths behind - Wonder what MPG they get tho??

[p fandango]

That sounds quite acceptable - nature of the beast. But when you consider that, as I followed a flat-out 350Z up a long motorway slip road today and there was absolutely nothing in it, it ain't a bad compromise on the pounds for poke.


350Z's don't seem that quick unless the driver is spanking the nuts off it - I had one try to overtake me coming out of a village 30 limit, he got alongside but then what can i say - epic Fail :) he ended up about 3 car lengths behind - Wonder what MPG they get tho??
not many people know the 350Z uses an updated version of the old Volvo/Renault V6 that was used in the 240/760 & 960. When you think Volvo stopped using the engine in 1991 no wonder they struggle with it lol

be good to do a 350Z engine transplant back into a Volvo tho :dgrin:

[PNuT]

what can cause bad mpg appart from my driven , cheers

is it getting up to temprature & staying there?

[danny-R]

is it getting up to temprature & staying there?


if not, does that mean coolant temp sensor or themostat??

ever since we had the bad snow up here, mine has been sat at about 4 o'clock on the temp guage, where it has always been bang on level at 3 oclock??.

i have also seen a decrease in mpg. usually aound 27 but lately it's been averaging low 20's.

cheers

[PNuT]

if not, does that mean coolant temp sensor or themostat??

ever since we had the bad snow up here, mine has been sat at about 4 o'clock on the temp guage, where it has always been bang on level at 3 oclock??.

i have also seen a decrease in mpg. usually aound 27 but lately it's been averaging low 20's.

cheers

yep, most likely the thermostat, especially if its taking a while to get there

[leet5r]

is it getting up to temprature & staying there?

yeah it reaches normal temp and dosent move m8

[thebadger]

Are you using an external BOV? (dump valve) Also might I suggest a broken Lambda sensor or maybe a bad spark plug?

If you are on a standard recirc valve it may be shot & loosing you boost under acceleration, or if it's a bad spark plug you may be burning fuel in the exhaust system which may mess the lambda (O2) sensors reading. (means it may keep putting in more fuel to compensate & give you the low figures)

[LiamT4]

I know someone with a 98 v70 2.5t awd auto, checked his mpg this morning and it reads 18.2mpg. The last time he reset it was months ago, his car is in good condition its just that 95% of his driving is around town with short journeys. Heavy+awd+auto+big engine+short journeys=crap fuel consumption!

[leet5r]

Are you using an external BOV? (dump valve) Also might I suggest a broken Lambda sensor or maybe a bad spark plug?

If you are on a standard recirc valve it may be shot & loosing you boost under acceleration, or if it's a bad spark plug you may be burning fuel in the exhaust system which may mess the lambda (O2) sensors reading. (means it may keep putting in more fuel to compensate & give you the low figures)

i think the recirv has a split in it m8

[thebadger]

Then replace it or blank it!

My "dead dump valve" post in the P2 section has a link to the very pretty Forge replacement unit that will skin you for £140 (inc post & vat) which could never fail as it's an all alloy unit!

I went from 16mpg average to over 19mpg average in 3 days! Though I still need to sort my O2 sensor!

[jez.w]

I agree that 17mpg around town driving seems normal, and is what i get. I get low to mid 30's on a motorway run, and 28mpg as an overall average. My car is an auto (with Rica 280) and uses a little more fuel around town than my old manual 850 t5 did, not much difference on a steady run between manual and auto though. Rica remap improved my mpg if driven sensibly, it is a little worse if driven harder (20mpg).

When i first got this (auto) car I got 460miles from a full tank on a motorway run with a fully loaded car at steady 70mph, i was trying to drive as carefully as poss to see how many miles i could get. Sadly It can be quite addictive looking at the mpg computer. I dont worry about mpg too much now as i love the car and dont mind, i leave my fuel computer on miles to zero and just drive according to the conditions.


Auto is the best drive by the way!!!!

[TenaciousC]

Don't know if it's relevant on Volvos, nut on my Nissan, the lambda sensor was not properly grounded and as a result failed the MOT emissions test. Was also getting poor MPG. You might want to check electrical continuity between the lambda casing and the rest of the car.

You can read more here:

http://www.sxoc.com/vbb/showthread.php?t=444243