why am only getting 25 mpg

Anonymous · February 5, 2011, 11:37

bought this car in nov 2010 and since owning the car i have never acheived better than 25 mpg, the car dosnt burn oil and compression is very good in 180s bought the car as they are very good looking and great to drive and supposed to be very ecconomical unfortunatley mine gets nowhere near book figures.

Ilogik · February 5, 2011, 12:19

Quote from: "safron"bought this car in nov 2010 and since owning the car i have never acheived better than 25 mpg, the car dosnt burn oil and compression is very good in 180s bought the car as they are very good looking and great to drive and supposed to be very ecconomical unfortunatley mine gets nowhere near book figures.

Where do you drive it? stop start traffic? do you have the heating on? do you drive it hard? im getting far worse mpg driving short journeys 5 min journey takes up to 15 mins in morning due to traffic, and im getting roughly 16mpg i worked out. Also do you do it with the amount of litres your getting or you just going on £20 last year gets me less than £20 last week?

muffdan · February 5, 2011, 14:07

Is the check engine light on?

Anonymous · February 5, 2011, 14:13

Lots more info please.

stargazer30 · February 5, 2011, 19:15

Could be worse mine only get 19mpg. But then again it does have a 2.5L Petrol turbo engine in it s:lol: :lol: s:lol:

tomcoolj · February 6, 2011, 01:22

How badly does putting the heating on effect MPG? I didn't realise it would make a noticeable difference?

evileye_wrx · February 6, 2011, 02:34

First things I would do would be to clean the MAF with Carb Cleaner and take off the battery for 30 mins to reset the ECU

Phil

creamykiwi · February 6, 2011, 08:48

not that I've actually got round to cleaning my MAF yet s:oops: :oops: s:oops: (i will, honest!) but even without that, i notice a marked difference in fuel economy depending on if it's a week i drive proper journeys to friends/parents/work, or one of those weeks where all i do is drive to the hospital a mile away to collect julia in the middle of the night... i haven't worked out exact figures but it chews petrol doing tiny journeys...

evileye_wrx · February 6, 2011, 11:22

Check the tyre pressures as well. President Obama told you to

Phil

vatovey · February 6, 2011, 18:25

I thought the heater was using heat generated naturally by the engine, and didn't have any effect on MPG.

Having air-conditioning on would though.

frogger · February 6, 2011, 20:22

+1

Heater is using hot water from the car's cooling system, and even on full the matrix is not capable of dispersing enough heat to prevent your engine getting up to temperature - therefore no effect on mpg from this point of view. From the fan point of view, electrically driven, and altenator is always being driven, so no effect there either.

Air-Con though - has a clutch and will sap a tiny bit of economy/power when on and remove most of the load when off.

Tyre pressures and MAF are hugely influencial by comparison.

creamykiwi · February 6, 2011, 20:31

Quote from: "frogger"Tyre pressures and MAF are hugely influencial by comparison.

right, i'm spending an afternoon doing my MAF as soon as i can steal the garage again s:)

s:)

muffdan · February 6, 2011, 20:32

I have to agree, I don't think heaters on/off will have any noticeable effect on fuel efficiency. Minor point, but the alternator puts more drag on the engine when more electrical load is being pulled. With my car the revs drop slightly when I turn my headlights on.

JiMR2 · February 6, 2011, 21:43

let me know how you get on Carla! I took mine apart and to be honest, didnt have a clue what bit i was supposed to be spraying... the lil wire inside looked scarily fragile so i put it all back :S

tomcoolj · February 6, 2011, 21:47

In previous cars I've had, with air con, on it used to destroy the MPG and there was also a noticeable loss in engine power. But I haven't got air con my MR2 anyway, so its not a problem.

Personally, I'd recommend servicing the car too, especially oil wise

phillywilly69 · February 8, 2011, 15:35

little bit off topic but a couple of years ago on top gear when clarkson drove an audi to scotland and back on one tank of petrol ,he said about the heater using more gas and froze on the journey -i still dont believe him ,also he said when you come up to a junction or lights ,coast up to them and press clutch at last min and while you coast in gear you use NO fuel at all !!!,but surely the engine is still firing so its using fuel and if you coast at say 2000 rpm you would be better throwing it in neutral and ticking over at 800 rpm up to the junction

? s:crazyeyes: :crazyeyes: s:crazyeyes:

roger · February 8, 2011, 16:13

Quote from: "phillywilly69",also he said when you come up to a junction or lights ,coast up to them and press clutch at last min and while you coast in gear you use NO fuel at all !!!,but surely the engine is still firing so its using fuel and if you coast at say 2000 rpm you would be better throwing it in neutral and ticking over at 800 rpm up to the junction ? s:crazyeyes: :crazyeyes: s:crazyeyes:

We've had this conversation before. Fuel injection is different to the old fashioned carburation. When you are coasting in gear, no (or the tiniest amount) of fuel is sent because the engine is still running under the momentum of the car. Put it in neutral and it has to send more to keep it idling.

Our Civic has an Eco (spit) indicator which shows it perfectly.

aaronjb · February 8, 2011, 16:29

Quote from: "roger"
Quote from: "phillywilly69",also he said when you come up to a junction or lights ,coast up to them and press clutch at last min and while you coast in gear you use NO fuel at all !!!,but surely the engine is still firing so its using fuel and if you coast at say 2000 rpm you would be better throwing it in neutral and ticking over at 800 rpm up to the junction ? s:crazyeyes: :crazyeyes: s:crazyeyes:

We've had this conversation before. Fuel injection is different to the old fashioned carburation. When you are coasting in gear, no (or the tiniest amount) of fuel is sent because the engine is still running under the momentum of the car. Put it in neutral and it has to send more to keep it idling.

Yep, no fuel at all is used - the injectors are switched off when decelerating in gear and above ~1800rpm. Infinite fuel economy.

Quote from: "creamykiwi"
Quote from: "frogger"Tyre pressures and MAF are hugely influencial by comparison.

right, i'm spending an afternoon doing my MAF as soon as i can steal the garage again s:) s:)

It only takes 5 minutes! s:lol: :lol: s:lol: Ok, maybe 10 if you're very careful s;)

s;) Disconnect negative lead on battery (10mm nut), unplug MAF, unscrew two small phillips screws (don't drop them!), yank on MAF. Squirt carb cleaner 'up' inside the tube of the MAF and then all over the little bulb on the side (little bulb is air temperature sensor, the actual hot-wire element is barely 5mm long and 2mm diameter up inside the top of the 'tube'). Dry off outside, push back in, do up screws, plug back in, have cup of tea.

muffdan · February 8, 2011, 16:34

.. and then reconnect your battery s;)

s;)

aaronjb · February 8, 2011, 16:44

Quote from: "muffdan".. and then reconnect your battery s;) s;)

I always forget that bit! s:lol: :lol: s:lol:

muffdan · February 8, 2011, 16:46

How far down the road do you get before you notice?!

aaronjb · February 8, 2011, 16:48

Quote from: "muffdan"How far down the road do you get before you notice?!

Not that far, I run out of puff after about 25 yards s:lol: :lol: s:lol:

Thinking about it - Carla, if you're at one of the Essex meets and I'm there, I'll happily clean your MAF for you. (You've no idea how tempting it was to make that a double entendre!)

Anonymous · February 8, 2011, 16:54

Quote from: "aaronjb"Carla, if you're at one of the Essex meets and I'm there, I'll happily clean your MAF for you.

Quality Aaron, quality. s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:

aaronjb · February 8, 2011, 16:56

Quote from: "nelix"
Quote from: "aaronjb"Carla, if you're at one of the Essex meets and I'm there, I'll happily clean your MAF for you.

Quality Aaron, quality. s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol: s:lol: :lol: s:lol:

Oh c'mon.. this is me.. it could have been worse! s:lol: :lol: s:lol:

markiii · February 8, 2011, 16:58

so you'd have to incapacitate her first by disconnecting teh electrics then Aaron?

is this your normal approach?