Drop In Fuel Economy

[hopper]

Hi

Since my car has come back from its service, my aygo's fuel economy has dropped my nearly 10%, so much so i ran out of fuel on reserve tank run (20miles) that i have done with no problem at least 10x before. i used to get about 112miles from the first blob, now in only getting 98mile at best. anyone experianced this before or have any ideas what the problem may be.

The 98mile blob run is the same a the one i get 112miles, its 90% A roads and motoways. Tyre's are 34psi on both runs.

thanks

hopper

[Parts-King]

There are no settings your dealer can change to improve/worsen your fuel economy, so don't rush to blame him just yet

It is most likely down to the cold weather we are having/had

Never rely on a fuel tank's reserve feature, it is not an exact science, and one day you WILL run out

There is a possibility they have used a slightly thicker oil, but I doubt it would make that much difference, the weather is the most likely cause

Kingo

[Demonic Angel]

I experienced the same thing recently (quickly depleting reserve tank while on the motorway), where just before I got on it beeped to say it was low and then when I got off 12 miles later it was flashing faster than I'd ever seen it flash before. But it was just after the very bad weather so that's what I put it down to.

My first blob also went down by about 10% on the last fill up, but I assumed it was more down to my "dramatic" driving style

My service was in October so not to blame.

[Unklian]

There are no settings your dealer can change to improve/worsen your fuel economy, so don't rush to blame him just yet

It is most likely down to the cold weather we are having/had

Never rely on a fuel tank's reserve feature, it is not an exact science, and one day you WILL run out

There is a possibility they have used a slightly thicker oil, but I doubt it would make that much difference, the weather is the most likely cause

Kingo

Or.........

With the current financial mess......

The dealer has cut an extra key for your car and they pop by

of an evening and syphon a little bit of fuel out.

Ian.

*this is not helpful, sorry*

[Parts-King]

Unklian: *this is not helpful, sorry*

.......But amusing

[gordonh]

If it's the first fillup since the service there is a chance that the car was left running in the workshop etc whilst they were messing with it.

[hopper]

thnaks for the reply, its had atleast 6 fill ups since then and the results have been around the same, at first i thought it was just down to my driving style but on the last couple of tanks i've been driving like a saint, the whole running out of fuel thing is the thing thats really made me think something is wrong, as i've made that trip so many times, and i've managed 35-40 mile on reserve before with out a problem..

Not sure the weather is much of a factor as it was just as cold before the service, maybe its the oil they have use though.

Thanks

Hopper

[gordonh]

Have you checked the tyres are inflated correctly ?

[johnan]

Hi

Since my car has come back from its service, my aygo's fuel economy has dropped my nearly 10%, so much so i ran out of fuel on reserve tank run (20miles) that i have done with no problem at least 10x before. i used to get about 112miles from the first blob, now in only getting 98mile at best. anyone experianced this before or have any ideas what the problem may be.

The 98mile blob run is the same a the one i get 112miles, its 90% A roads and motoways. Tyre's are 34psi on both runs.

thanks

hopper

Have you checked for excessively hot brake drums/discs after a run?

Maybe something in the service caused a brake to start binding, or not release fully...just a long shot.

[adilmon]

Coolant temperature really does affect fuel economy. Heat transfer is greatest where there's a big difference between the coolant and combustion chambers/cylinders. The heat robbed from the burning fuel reduces the power output and therefor reduces efficiency.

Simply, a warm engine is running efficiently and the colder it is, the longer it will take to get the coolant up to temperature.

If all else is equal, I suggest checking the air filter isn't too dirty and suffocating the engine. I've had a filter change ignored by Mr T simply because they didn't have it in stock.

[Jan van de Wouw]

If it really is since it went in for a service, I'd go back.

May even be such a simple thing as a plug to a sensor that's loose...

[Cokeman]

I too have noticed a drop in economy, which I have just put down to the extra cold weather. If and when it was used, we sometimes left it running to warm up and thaw out the windows etc, so expect it to come back to "!normal" levels now it has warmed up a tad. I have noticed that on this latest fill, the first blob disappeared after 108 miles, whereas over the last couple it was going at about 85 miles.

The 41 mpg is the worst it has achieved.

date mileage since last fill cost litres MPG Fuel Cost ppl

02/07/2008 8594 409 £40.92 35.00 53.12 £1.169

23/07/2008 8865 271 £30.19 26.51 46.47 £1.139

29/08/2008 9227 362 £10.04 9.22 short fill £1.089

13/09/2008 9351 124 £37.37 34.00 51.12 £1.099

15/10/2008 9745 394 £38.65 36.50 49.07 £1.059

26/11/2008 10099 354 £31.47 35.00 45.98 £0.899

31/12/2008 10450 351 £30.07 35.00 45.59 £0.859

14/02/2009 10774 324 £31.36 35.68 41.28 £0.879

you'll notice the way the cost of the fuel has come down too. The £1.169ppl is the dearest fuel I have ever had to buy, and the cheapest has been £0.829 ppl.

[ViR2]

well maybe it's a bit offtopic, but my cars mileage has improved gratefully by just changing oil from 5w40 to 5w30 ;)

[Wild west Drifter]

Currently getting 47mpg, never dropped below 44mpg yet and that has included some serious up and down the box on nice twisty roads

[mela]

I feel the same about my car. It is 12950 km in the clock and 7 months. Recently I feel my car is not as economical as it used to be. Maybe I'm wrong but I'll tell it to Toyota when I go there for the first change of oil that is soon.

Other thing I notice is that when I'm acelerating I hear the normal brrr but there's some different noise with it also which I never noticed before like a ssss.

Sorry for explaining the sounds this way but that's what it is. Do you notice the same?

[Bigmo]

Hello folks. New on here and this is my first post. Having owned Aygos for 3 years now getting on average anything from 310 to 400 miles per tank, I turned to super unleaded when consumption fell by 10%. Now I'm averaging 380 to 400, all town roads, no motorways (the car is strictly a town car.....also, hardly ever use the aircon).

[Smoothound]

If it really is since it went in for a service, I'd go back.

May even be such a simple thing as a plug to a sensor that's loose...

^^^ What he said.

If they changed the spark plugs, could be a faulty plug/loose HT. Or as he says, a loose plug to the lambda or airflow/pressure sensor

[Rotten Ali]

I feel the same about my car. It is 12950 km in the clock and 7 months. Recently I feel my car is not as economical as it used to be. Maybe I'm wrong but I'll tell it to Toyota when I go there for the first change of oil that is soon.

Other thing I notice is that when I'm acelerating I hear the normal brrr but there's some different noise with it also which I never noticed before like a ssss.

Sorry for explaining the sounds this way but that's what it is. Do you notice the same?

hope it's not that slipping clutch "ssss?" if it is then watch out for the brake-down routine:-

"somethings wrong"

"i'll take it to the dealer soon"

"better take it now"

"oh-dear it's broke!"

[gordonh]

If its a slipping clutch you will be able to smell it when you stop.