Much has been written concerning possible vehicle improvements in order to achieve better fuel economy for the standard Series Land Rover engines. However, the greatest single factor in reducing fuel consumption is careful use of the accelerator pedal. Gradual acceleration and deceleration is the key to better fuel economy and nothing else can achieve comparable results.
The greatest obstacle to achieving better fuel economy is, sadly, often our fellow road users and our attitude towards them. Some drivers regard journey times as a modern day evil. They rarely, if ever, drive a vehicle based on old technology and whilst many delight in seeing classic vehicles, and Series Land Rovers in particular, they will not tolerate being behind one. Our greatest fuel consumption occurs in town areas and there is little to be gained in trying to save a few seconds journey per street, so on that basis, if we accelerate more slowly then we are doing our bit towards saving the planet. On the open road however, allowing space for others to pass, where safe to do so, is good road manners and tends to foster a better image of Series Land Rover drivers.
We can modify our accelerator use with practise, but to get reliable positive feedback on just how our foot is behaving, then we need to fit a vacuum gauge. Such a gauge can also be a valuable aid in engine problem diagnosis and tuning. A vacuum gauge can indicate problems with exhaust manifold leaks, cylinderhead leaks, valve timing, ignition timing, wrong spark plug gaps and more. Basically, the higher the manifold vacuum when driving, the less fuel is consumed.
A fuel leak can considerably raise apparent fuel consumption. Petrol leaks can easily go unnoticed in warm weather
and the main problem areas to check are the fuel tank seams and fuel pipe unions. Those perished rubber fuel pipes to the carburettor are a particular concern, as was noted on a 2009 USA homepage of this website (follow the link). The problem has not gone away and may become more of an issue as the percentage of ethanol increases in fuel in the UK.
If the ignition timing is incorrect then fuel economy can be seriously affected. It's important to remember that if a timing light is used to set ignition timing then the engine must be idling at no more than 600rpm else the distributor advance weights will operate and the static timing will be wrong. The dwell angle (or else the contact points gap) and the spark plug gaps need to be set correct also.
Solex, Zenith and Stromberg carburettors on Series Land Rovers each have their own faults that can lead to poor fuel economy and Zeniths are notoroious for such problems even when quite new.
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