Poor MPG

[2003bluecat]

Ok, so I've had my '2 for nearly 4 weeks now, doesn't time fly!!

So far so good, but I'm having issues with the fuel consumption, by my calculations I've been getting between 22-26mpg (off the top of my head, the calculations aren't with me at the moment). It is mainly city driving, short trips, so I never expected it to be great but this is pretty poor. I've been running of vPower and do around 150 miles a week, there are no warning lights and my right foot isn't THAT bad   s:roll: :roll: s:roll:  

So, I've done a little search and decided I need to do the following before spending money trying to find the problem:

1. Clean the MAF sensor
2. Clean the injectors
3. Clean the O2 sensors

Would this be a sensible place to start? And is there anything else anyone could recommend that might help.

I know this topic has been done to the death so any help would be appreciated   s:bounce: :bounce: s:bounce:

[uktotty]

Sounds good to me, not aware of anyone cleaning the O2s however!
Have you tried an Wynns type treatment also?

[Goeman]

The MR2 has the largest span of MPG out of any car I've ever driven. I usually get between 28 - 32mpg but the extremes have been between 15.6 - 42.3mpg for me. I honestly wouldn't expect anything better than the high 20's for town driving.

No harm in doing the things you mentioned but I wouldn't use any sort of cleaner on the O2 sensors.

[kentsmudger]

Might be worth looking at the air filter, does that need replacing?
I get around 30 most of the time and up to 40 on a long constant 70mph.
Click below to compare what other Roadsters are getting on Fuelly

[loadswine]

I've never got more than mid to high 20s round town from a stock 2either, so if a lot of stop start, then there may not be much to worry about. Take it on a run and see what you get there. My old 2 used to get high 30s to low 40s depending on how hard I went. Some get more than that.

[Anonymous]

I tried vPower a couple of times and found that my mpg DROPPED from mid 30's to low 20's!
Unless you are chipped anmd mapped I do not think that there is anything to gain by using vPower or similar.  Run a few tanks of regular unleaded and see how it goes.

[2003bluecat]

Thanks for the quick and useful responses. I will have a go at what you've said and see what happens.

The o2 sensor cleaning came up in this thread, although it is rather old http://www.mr2roc.org/phpBB3/viewtopic.php?f=11&t=3973&p=50095&hilit=high+fuel+consumption#p50095

In all fairness it's not really that much city driving. I imagine that to mean a lot of stop start driving but when now I think about it I'm driving on a and b roads probably more both in terms of miles and time.

But it's reasurring to know it may not be too unusual, if slightly more expensive. I don't really mind if it is, it's worth it for the fun and I was only getting 22-25mpg on my old car anyway   s:bounce: :bounce: s:bounce:  

With regards to the vpower I had seen it recommended by many on here so automatically went for that, I've always found it more responsive in other cars I've driven. But is it recommended on here mainly by tuned car owners? Could be interesting to try something else though to see if it does make a difference, thanks.

[Mad Matt]

On all the other cars I've owned I've had better mpg by using higher octane. However on the MR2 I didn't notice such a big difference. Unfortunately I went Unichip before I had time to do more than a couple of runs, so now I have to use 98! My theory was going to be that it might be because the MR2 is direct injection but I can't see why that'd make a difference.

I get a low of about 36 if I drive hard and a norm of about 39. That means two hours at around 75mph and an hour crawling through traffic, then a few days of two times four miles in traffic, then the long run again.

[SteveJ]

the MR2 is direct injection

Errr - No it isn't   s:roll: :roll: s:roll:

[Mad Matt]

Do you know what? You're right  :-) :-) :-)

Now what made me think that? Oh I know, the MR2 seems to have better torque than the 1.8 Fiat engine in the Barchetta (170Nm vs 158Nm) yet they're both 1.8s with variable valve timing and similar bhp (138 vs 132) and I thought I'd read somewhere..... Oh well, that'll teach me to pay attention to what I'm typing instead of telling the kids off at the same time!

Anyway, I did two or three tanks on 95 with very little difference in mpg when the car was in standard form. Whereas the Fiat, for example, showed a marked increase in mpg if ran it on 98 (as did my last several cars).

[Thudd]

Has it got any oil in?
Check fluids, check filter, clean maf, give it an italian tuneup.

[2003bluecat]

Just a quick update on the petrol usage.

I checked all fluid levels and the air filter, everythin looked fine. I've continued to use vPower and have perhaps been thinking a little more about when I change gear in general driving. I've been changing at around 3k but trying to keep the revs above 2k so as not to labour the engine.

Over the last few tanks I did notice a little improvement (possibly due to having the roof up more and the air con on less  s:cry: :cry: s:cry: ), and the overall average mpg since I got the car is now just over 26mpg.

This week I have ran a redex fuel injector cleaner through and today I cleaned the MAF, so we'll see how it goes.

I must add that cleaning the MAf has made a noticable difference to the responsiveness of the throttle; when easing off it is much smoother and seems to down change gears smoother too (it's an SMT gearbox). The cleaner I used came out filthy brown when cleaning, so it looks like it needed it.

So if I don't see any improvements from now, at least I have a better driving car and know there doens't appear to be any problems with how it runs. Thanks for all your input   s:bounce: :bounce: s:bounce:

[Anonymous]

Measured mine over two tanks, first time was just over 45mpg, second was over 46! Though this is 70% motorway.

[Chris_h]

Measured mine over two tanks, first time was just over 45mpg, second was over 46! Though this is 70% motorway.

Who needs diesel! - you'll probably leave yourself wide open to some ribbing by achieving those figures  s:) s:)

[normanh]

Exactly what I get jcrossi, nothing wrong there.


norman

[chuckie]

Normal for me is about 40mpg on most types of driving, nothing too excesive as the car has bigger ba@!!s (and mor ability tha I do)

Chris

[Anonymous]

I don't know if it is just me but kentsmudgers ling doesn't work   s:? :? s:?  

So try...........THIS.......Mine is top one (not the best) for the 2002 vintage   s:wink: :wink: s:wink:

[trickyD]

I'm getting 15-20 at the mo!!! :O
Town driving and some MWay...

I do have an ECL light for the O2 so maybe that's the next step then clean the air sensor...

Got to see 30 on a run!

[AndyM]

I'm getting 15-20 at the mo!!! :O
Town driving and some MWay...

I do have an ECL light for the O2 so maybe that's the next step then clean the air sensor...

Got to see 30 on a run!

Definitely get that sensor checked and clean the MAF. I did a very fast and revvy 300 mile trip a few days ago and it only dropped to 28!

[trickyD]

My ECL error was the P0135 (heater) error, so apparently doesn't effect operations I will change it anyway.
Calculated ~20mpg today  s:( s:(