Why does the small engine (650cc) of my Pajero Mini consume a lot of fuel?

Thursday December 5 2013

The engine of a Mitsubishi Pajero Mini. Despite being liked for its small

The engine of a Mitsubishi Pajero Mini. Despite being liked for its small engine size, which would automatically translate into less fuel consumption, someone feels otherwise. Some motorists forget to factor in certain issues and end up spending more even with small engines. Net Photo 

By Paul Kaganzi

Why does Mitsubishi Pajero Mini 1995 of 650cc consume more fuel for example 14-15km per litre yet a Toyota Tercel 1996 with 1330cc consumes 15-17km per litre? I thought that the small cc consumes less per litre Please kindly advise. Richard Olele.

There are several factors that affect the fuel consumption of a vehicle and engine size is only one of them. It seems logical that the smaller 1995 Pajero Mini 650cc (cubic capacity) engine should consume better than bigger 1996 Toyota Tercel 1,330cc 4EFE engine.

However, there are other dynamics which affect fuel consumption and override the engine size factor. In this case, the engine technology influences the fuel economy of the Mini and Tercel.

The electronic fuel injection with the double overhead camshaft drive train make the Tercel’s bigger engine more fuel efficient because the fuel amounts delivered are electronically determined. While the DOHC valve system ensures sufficient and timely delivery of air to guarantee better power of 66 kilowatts using lower engine revolutions of 5,500 rpm.

On the other hand Pajero Mini’s 4A30 engine has the less efficient old electro carburetor with the single overhead camshaft drive train. As a result, it provides a smaller engine power of 37 kilowatts at higher engine revolutions of 7,500 rpm. This makes the engine less efficient. The four wheel drive transmission type on the Pajero Mini adds load on the engine and the consumption of fuel.

The canopy like shape or design of the Pajero meets a lot of dynamic wind resistance which increases vehicle load on the small engine and fuel consumption. On the other hand,Tercel’s more aero dynamic saloon body meets less wind resistance and has better fuel economy.

The engine and tyre condition will also affect fuel consumption. If the engine spark plugs, air filter and throttle body of either car are not well maintained then it will not be fuel efficient. Over inflated or wrong tread type tyres may increase the fuel consumption of a vehicle regardless of its engine size.
Driving style also affects your fuel economy. Aggressive take offs, delay to shift from lower gears, idling for long in traffic jams and overloading may also make a vehicle with a smaller engine less fuel efficient.

To help improve the fuel consumption of your Pajero Mini, you ought to switch to Shell FuelSave unleaded petrol which lasts longer. It cleans your engine valves to prevent energy loss through accumulation of deposits which absorb and waste fuel. Fuel save unleaded has additives which lubricate the upper piston to allow less frictional loss of energy during piston movement to improve your fuel economy. Finally your driving style can also help save on fuel.

I am looking for a cylinder head for my vehicle, a Toyota Wish with engine no.1ZZ-1669996, chassis ZNE 10-0113322. I will appreciate any recommendations for either a new or used one. Thanks.

There are a couple of dealers for used but quality spare parts for Japanese vehicles. If you call me directly, I will provide their details so that you can secure the cylinder head you are looking for.
Let me hasten to add that it is important that you read the engine number where the used cylinder head is to be removed and match it with your engine number. That way, you will be sure you are getting the right part.

My Toyota Premio consumes water yet the temperature does not rise up and the radiator is clean. What is the cause of water loss?

Loss of vehicle engine coolant fluid can happen even in situations where there is no apparent overheating or failure of the radiator. However, in the long run, persistent coolant fluid loss will lead to overheating and damage of vital engine components such as the radiator or cylinder head.

In your case, your technician should carefully examine all rubber or plastic coolant hoses between the radiator, expansion coolant reservoir and the engine. Sometimes these hoses develop hairline cracks due to age and leak coolant when the engine is very hot. In situations where you take too long to renew the coolant and drive your car with plain water, corrosion accelerates this sort of situation.
Corrosion will also damage the water pump and thermostat seals leading to leakages. Unfortunately, water without coolant dries quickly and may not be easy to spot and pinpoint the leak.

Carefully examine the water pump, thermostat or sometimes depending on your Toyota engine type, check below the engine throttle chamber where coolant is used to help with performance.
Examine the colour of your engine oil using the dipstick to confirm that it is not chocolate brown, a sign of cylinder head gasket damage and loss of coolant as it mixes with engine oil. The colour of coolant in the reservoir might also be the chocolate brown. Lastly, confirm that the in cabin ventilation system with the heater does not leak coolant on the passenger floor.
If you check all these components, you will find the source of coolant leak on your Premio.