Technical Petrol consumption for mk2b Punto

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Technical Petrol consumption for mk2b Punto

I am though assuming a car with computerised fuel injection can build a reliable comparison measure of fuel consumed so that last months similar driving can be compared to this months similar driving.

So for example did changing the coils make such a big difference? I am not so sure yet. Normally i make many small journies. Idling for example definately eats into the petrol MPG consumption surprisingly quickly.

Afaik the car uses the number and duration of injector pulses as an approximate measure of fuel usage and the odometer for distance. The calculation will be approximate and will change with age and tyres.
I consider the display to be a toy and a distraction and never put much trust in them.
Petrol engines are horribly inefficient at idle because to idle they have to close a throttle plate and are literally choking the engine.
 
Afaik the car uses the number and duration of injector pulses as an approximate measure of fuel usage and the odometer for distance. The calculation will be approximate and will change with age and tyres.
I consider the display to be a toy and a distraction and never put much trust in them.
Petrol engines are horribly inefficient at idle because to idle they have to close a throttle plate and are literally choking the engine.

Tyres do not change much if you only drive 5000km per year like I do and tyre inflation levels just give a variable odometer reading that meanders around a central point

So in principle the injectors should be able to provide a method of calculating the fuel used whatever the car is doing which can at least be used for my own personal comparison purposes. For example if the next time I travel at 80km per hour on a round trip and I am not using something like 4.7l per 100km i might suspect some issue with the engine drive chain brakes or tyres. and I do not have to wait to fill up to find out. That is at least my best current theory.

On the other hand if for the same journey in the same conditions the consumption is all over the place with no reason or rhyme to it then I will know it is just a toy. :)
 
If you think that the consumption is bad on short journeys, it could be a bad thermostat. Because the weather has become colder the car will not warm up quickly and you will run on the choke more (rich mixture).

The exhaust condition can affect engine running, for example if a leak near the manifold is letting air confuse the lambda probe reading, so it could read "exhaust mixture too weak" and the ECU will give more fuel to compensate.
 
Hiya Folks, Got a Punto 1.2 16v speedgear a few months ago for my daughter to learn in, while I run a 1.3 MJD 75hp Qubo with the duel-logic gearbox.
The Punto is blooming amazing on petrol, it pushes my diesel Qubo. According to the onboard computer, (checked using pen & paper), the cars doing 45.7 mpg. By paper 45.8 mpg...........its used on a 16 mile run, on easy roads which must help. But well impressed.

Cheers Qube O.
 
Hiya Folks, Got a Punto 1.2 16v speedgear a few months ago for my daughter to learn in, while I run a 1.3 MJD 75hp Qubo with the duel-logic gearbox.
The Punto is blooming amazing on petrol, it pushes my diesel Qubo. According to the onboard computer, (checked using pen & paper), the cars doing 45.7 mpg. By paper 45.8 mpg...........its used on a 16 mile run, on easy roads which must help. But well impressed.

Cheers Qube O.

I got the same for my first car, apart from a few small faults she's perfect
 
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