How to get good fuel economy from your car No Comments

This blog is about helping the serious car owner on how to get good fuel economy out of their car.

We will talk about why fuel is so expensive.  & a general overview how the dynamics of a car engine with a little technical understanding- from this you can adapt your driving style.

Why is petrol so expensive now?


1/ Vladimir Putin and his pyrrhic war on UKRAINE. – Russia was the world biggest exporter of oil & gas- this has now been severely capped.

2/ Arab based OPEC deliberately capping oil production keeping Prices high designed bigger profit margin referred to as price gouging.

Why doesn’t Australia makes its own petrol?


Our business structure with high wages, Unions makes us too expensive- where countries like Indonesia, Malaysia and Thailand have a cheaper labour rate & work force thus producing fuel far cheaper than we can.

Vital Components on your car which determine the consumption of fuel:

The fuel injector

 Is computer controlled- The injector (injects) sprays precise metered fuel at a precise time, Proper maintained & cleaned injectors every 100 000km deliver precise spray patterns making combustion efficient

The Battery

The heart of electrics- volts (electrical pressure) and current (electrical flow) a poor performing battery reduces the ability of the injector to spray @ the right time- The precise window when the injector is supposed to energize & spray may be missed especially when starting the vehicle- A proper charged battery is vital.

The computer

The computer is a data calculator- it takes all the signals from inputs- works out the equations & then energizes or activates the fuel injector to switch on at a precise moment for a precise time- its essential that the correct data gets to the computer to do its job. If the data is wrong its impossible to tune the vehicle referred to as GARBAGE IN- GARBAGE OUT.

Air flow meter, Map Sensor, Air Temperature sensor

The computer must know the correct amount of air that is entering the engine, not only the volume of air, but the density- which is measured by air temperature- the ideal equation is 14.7 parts of air to one part of fuel this has been calculated as the ideal ratio & gives best fuel economy in cruise condition & idle.

Temperature sensor

The temperature sensor measures the coolant temperature- when temperature is cold the computer calculates this & keeps the injectors on longer until the correct temperature is achieved.

The throttle position sensor & accelerator position sensor

The throttle position sensor & accelerator pedal sensor are the only sensors that are controlled by the driver- In diesels the throttle is on controlled by the injector injecting more fuel from the accelerator sensor data- while in petrol there is a air flow throttle or flap which controls air flow- the position of the accelerator when pressed is referred as “ tip in” or when relieving pressure from the accelerating pedal this is known as “tip out”- its here when load dramatically changes.

Crank shaft & camshaft sensor correlation

The Crankshaft & camshaft sensors tell the computer the exact position when to inject the fuel- these sensors enable the computer to see & tell the injector to fire!

Exhaust oxygen sensor

After combustion has occurred, the gases are then moved to the exhaust- oxygen content is measured in the exhaust by a narrow band or wide band oxygen sensor- too much oxygen- too lean- too little oxygen to rich this information is fed back to the computer which is referred to as closed loop.

These sensors are the main data the computer looks- if any one of these sensors play up then everything else goes south- you cannot get good fuel economy with a fault in any of these sensors & there are others I have not mentioned- this why you must get your car scanned when you have a service.

Driving Characteristics

Do not use e10 its cheap & that’s about it- its like going to a five-star restaurant only to eat McDonalds.

Let your car warm up when cold starting- let the heat get to the engine try to avoid driving straight away- in cold start mode the injectors are spraying excessive unmetered fuel – let the car warm up and reach close loop mode. Keep constant vigil of overheating- this can have a disastrous effect on the engine. Correct engine temperature is vital for good fuel economy

Cruise control- when you are travelling at consistent speed over 80 kmph hit the cruise control button- the cruise control sends the car into a sort of steady state- once in cruise mode the computer activates the Egr- exhaust gas recirculating which is an inert gas- this inert gas takes a lot of combustion space where the air & fuel would be- it keeps the engine combustion cooler & produces far better fuel economy.

Excessive throttling & braking- listen to your engine speed- avoid excessive tip in state (accelerating) listen to your engine have consistent note & of course watch your vehicle speed- it’s important to keep in tune with your car for correct gear changes. Avoid excessive braking- when you brake too much unnecessarily you lose momentum- which means you must accelerate to get up to speed this is where you burn up most of your fuel.


 ITS ALL ABOUT A FLOW- A CONSTANT FLOW OF POWER- sudden changes cause enrichment- listen to your engine you will feel the sweet spot & keep it that spot. There equally vital components like tyres- but the focus on this blog is to drive in a steady progressive state-The accelerator pedal is the tap for fuel delivery & you have control

Regardless of you cannot get good fuel economy with a poorly maintained car,

Call Manny 0411496621

 To get you car in tip top condition for Xmas & the New year

Please do not hesitate to call if there are any questions about this blog

To Serve, To Perform to Guide- I`m on Your Side.

  • Manny