why am i not getting the mpg i should?

[ttjoey]

hi all thanks for taking the time to read my post
having owned a k11 1.3 slx auto for six years and being very happy with it i thought it was time for something a bit newer and less miles[the old one had 130k on the clock] so i purchased a 2001 1.0 se auto,with 41k on the clock. the problem is i am only getting 30 mpg when my 1.3 gave 44 anyone got any clues? the car runs and drives great if a little slow on acceleration many thanks

 

[pollyp]

winter will lower any cars mpg below norm

 

[r-reg-sr]

and code reader is 20 quid for your facelift

 

[ttjoey]

thanks, whats a code reader? and where do i buy one for £20 quid.

 

[Stani1029]

1.0ltr are mostly worse on fuel due to the lack of power. I.e. needing to step on it more uphills etc. my 1.3 is giving me poor fuel economy at the moment but ill need to get used to that soon anyway haha!

 

[Muniek]

your oxygen sensor (lambda) might be an issue. With age they start to read the o2 wrongly and thus the car might use more fuel...

 

[TheSam]

Ive just changed my lambda and its given me an extra 80 miles from a tank, cleaning the MAF and the Idle control valve also helped dramatically

 

[Muniek]

TheSam - perfect info... so what are you getting on full tank of gas and "normal" (not sport) driving?

 

[Muniek]

Did you feel that the motor has more power after new lambda and cleaning? Do you have a flat spot around 4K RPM or did that go away after new lambda etc?

 

[r-reg-sr]

thanks, whats a code reader? and where do i buy one for £20 quid.

http://www.ebay.co.uk/itm/CAR-FAULT...iagnostic_Tools_Equipment&hash=item4ab039185c

 

[ttjoey]

thanks to all

thanks for your time just ordered one now, will let you know how i get on when it arrives

 

[TheSam]

Setting the base timing correctly smoothed out the power band. It was pretty much dead above 4k before that.

 

[oldspike]

Have a look at your front brakes TT. Calipers tend to bind which would cause poor mpg and acceleration.

 

[ttjoey]

i have run the code reader as per the instructions and it says i have no fault codes stored . the brakes were my first thought and they were replaced at my local garage new discs, pads and one caliper replaced rear drums cleaned greased and adjusted. just going to take a look at the state of the plugs before it goes dark thanks

 

[r-reg-sr]

i wonder if the reader can be tested by pulling a plug, lambda sensor,,maf or temp sensor. the reader works on loads of cars i think.

 

[ttjoey]

hi all checked the plugs and they are the correct shade of brown, when i had a good look around the engine bay i noticed a breather pipe not connected to anything it comes from the crankcases/gearbox on the right as you look in the engine bay i looked for were it may be disconnected from and it apears to be from the top of the carbon cannister do you think this might have some affect on mpg,also what is the maf i have looked in my old haynes manual but no mention of it thanks again for your time

 

[r-reg-sr]

theirs one breather pipe comes of the gear box,its left alone to breath. mine is
what i ment is to disconnect a sensor plug then run the code machine again to see if it picks up on it.
have you checked temp sensor and oxygen sensor?

 

[davedaveld]

Tires all pumped up tracking good I know they are basic but worth a check lol also I agree with whoever put about the 1.0 working harder it is very true

 

[ttjoey]

thanks again i have disconnected the 02 sensor and run it round the block up to temp and the code reader works, picked up on 2 codes po130[02 sensor circuit malfunction bank one sensor one] and po135 [02 sensor heater circuit malfunction bank one sensor one] i deleted the codes replaced the sensor run it round the block and rerun the code reader all well again look's like i should have hung on to my 1.3 slx if the economy on the1.0 is so bad. i researched the car before i bought it and it's supposed to do about 46 mpg going to try to be as light with the right foot as possible untill i swap back to a 1.3 anyway thanks to all for your time especially r-reg-sr.

 

[r-reg-sr]

check wheels spin freely

 

[ttjoey]

hi did this as soon as i realized mpg was so bad, that is what led me to take it to the garage to get the brakes checked for binding. the mechanic said with all autos you get some gearbox drag and the front wheels do not spin as freely as a manual in neutral i will put the car up on the jack tomorrow and check again and check my tyre pressures just to be sure .thanks

 

[Muniek]

the auto should use maybe 0.5-1L more than manual. I guess most mpg issues are lambda connected.

 

[ttjoey]

hi i was not able to check the wheels and pressure's today as it has not stopped raining all day here in sunny manchester i was thinking maybe i should try a new lambda or take it to one of these specialist diognostic places. been out in the car today on a 40 mile trip and tried not to put my foot down much but to be honest if you dont the car is painfully slow

 

[TheSam]

Mpg has a lot to do with the driver.