Technical Very poor fuel consumption, Fiat panda 1.1 active, where to look first

[varesecrazy]

Throttle body did look a bit mucky, generally oily, I didn't see a maf, although I don't know where it is.

Are these cars not rated for E10,

I haven't had a petrol car in 10 years, diesels my preference,

Will it do it harm running on e10

I have run all mine on Supermarkets cheapest offering for 20+ years.. mpg is still good.

Did the new plugs and leads sort your issues ?

 

[Revilo]

I have run all mine on Supermarkets cheapest offering for 20+ years.. mpg is still good.

Did the new plugs and leads sort your issues ?

Thanks, I believe a new set has made a difference,

I'm now getting around 300miles to a tank.
Fillup to fill up, so that's much better.

I don't feel it's quite as good as it could be but I can live with that.

I did notice a smoother idle, less missing,

A definite reduction in the stutter at low rpms when pulling away.

Power band has improved a little, it revs more freely.

I'm not sure there's much else can be done, maybe there's a little blowby or it's just a little tired old girl.

 

[DaveMcT]

300 miles to a tank in Exeter traffic is excellent fuel consumption.

 

[Yolanda]

I've just been watching an American video on utube the guy said that the correct air to fuel ratio was 14.7 to 1
Is that is that also correct for the UK This was for a petrol engine at idle.

 

[jrkitching]

I've just been watching an American video on utube the guy said that the correct air to fuel ratio was 14.7 to 1
Is that is that also correct for the UK This was for a petrol engine at idle.

Things aren't that simple. It depends on the type of fuel (adding ethanol changes the stoichiometric ratio), and whether you're trying to optimise for power or economy.

 

[timmycm850]

I would look at cam timing and has the air filter been checked/ changed

 

[koalar]

I've just been watching an American video on utube the guy said that the correct air to fuel ratio was 14.7 to 1
Is that is that also correct for the UK This was for a petrol engine at idle.

Not sure what the question is

But a O2 sensor at 0.45V is 14.7 to 1

The ECU is constantly add and taking away fuel to cross over this point

Under certain conditions it intentionally makes it rich and others such as deaccelerating it shuts off the injectors completely


I have no doubt there will be different strategies over time in the ECU for emissions . My eco averages .2V at idle slightly below the ideal .45V

 

[A3jeroen]

And the optimum is in Kg. So 1 Kg petrol to 14,7 Kg air...

gr J

 

[koalar]

My post is wrong

.45V is still correct

But 14.7 for petrol
And 14.1 for E10

 

[jrkitching]

The O2 sensor measures unburnt oxygen, not the fuel/air ratio directly. so should be controlling the mixture correctly whatever the stoichiometric ratio for the particular fuel you are using happens to be.

Just as well, given that the correct ratio for the fuel you buy depends on what percentage of ethanol happened to be put into that particular batch.

In the UK, fuel labelled E10 might be anywhere between E6 & E10, and some fuel labelled E5 is actually E0.

 

[Yolanda]

All good points, I didn't take note of what year the video was made

 

[DaveMcT]

Cars with catalysts run a stoichometic air/fuel ratio but its controlled by the ECU wording to O2 sensor values. It basically leaves a little unburnt hydrocarbon to drive the catalyst. Cold start is slightly richer until the O2 sensors are switched in as temperature comes up. A smelly black exhaust can be O2 sensors, failed catalyst or simply having the engine running too old. Check the thermostat. HOWEVER, a misfire will put excess oxygen down the exhaust. The ECU sees that as running too weak so it richens the air fuel ratio, making the misfire worse.

 

[steven toast]

25mpg isn't normal; I can't imagine how you'd have to drive one in good order to get this low.

Also check the thermostat is functioning correctly; there's a seal inside which often perishes and allows coolant to flow when it should be closed, so the engine never warms up properly. If the temperature gauge isn't at the halfway point after a couple of miles running, this is the likely cause. The Panda uses a LOT more fuel until it reaches normal operating temperature.

Double check by placing your hand on the top hose after starting the engine (be careful); it should stay stone cold for a few minutes, then warm quickly once the thermostat opens.

Hi jrkitching,

I did not realise that I even had a problem until I read your comment quite by chance,
The guage stays at the quarter mark; the fuel economy does not seem great, (I put that down to the horrendous fuel prices).

I will change my thermostat at the first opportunity.

Thanks for the heads up.

 

[DaveMcT]

Fuel prices don't worry me. I only put in £20 worth.
Trigger.