During one of our many trips through Fiji, I am replacing a fuel filter. This is no fun job as afterwards, everything smells of diesel fuel. During replacement, you need to fill the new filter with fuel, otherwise you cannot de-air the system properly.
A number of times I had blockage of the strainer inside the fuel tank and the only thing to do is empty the whole tank, remove it and clean it. Once you start filling bottles, you realise how much fuel actually goes into a tank (65 litres). If you don't have garage equipment to do this job, there is a lot of work involved in getting the tank empty.
The fuel tank is now empty and can be cleaned. The fuel is all over the place and it turned out that the inside strainer was blocked. This repair cost me 4 hours to complete.
This is the strainer that I found in the tank. It is clogged with fatty greasy particles. They are part of the crushed shell of copra during the process and caused by lack of filtering.
Once cleaned, I also punctured some holes in the strainer so as to minimise the chances that I will ever have to remove the tank again. After this, I always filtered oil before pouring into the tank.
This is my first fuel heater that I made from copper tubing, wound around the rubber hose of the cooling system. It never really worked well, because I could not de-air it properly.
The second problem was that it became really hot once I shut the engine down, as the fuel stops streaming through, but the engine is still very hot. I am not sure how hot, but I reckon it could get close to the spontaneous burning temperature of diesel.
It is also not very effiicient and can damage the rubber hose over time, So I removed it again.
My second fuel heater is a design from Tony Deamer in Vanuatu. It contains of a spiral of copper tube inside a larger pipe. The cooling liquid flows through the pipe and the fuel through the copper spiral. It works very well and the emissions are visually less than without.
After using it one day, a hose blew, causing a leak and subsequent overheating of the engine.
After three days the injector pump started leaking significantly. After removing the heater and lowering the coconut oil blend, it has ceased leaking.
When using this heater with a mixture of 40% diesel, 10% kerosene, 50% coconut oil, the injectorpump started leaking like hell. It was at the point where you could follow the car around the city, with the black spots of coconut oil on the road. Especially immediately after a cold start, it would easily create a pool of fuel under the engine. No good.
I visited some injector specialists here in Suva and they told me they can only replace the upper seal and have a standard set of replacement rubbers for the pump. It was going to cost over $600 just to get it out and work on it. Then I decided to finish the blend in the tank and get real; Why am I wrecking a good car with the juice of the nuts on the waving coconut trees?
Still, the question haunted me, why did it leak? Was it because of the increased temperature of the fuel? Was it because of the composition of the fuel? You would expect the fuel to leak through the seals if it gets too hot, but why would it leak the fiercest when the engine was still cold?
A lipid specialist from the local university offered a theory based on the chemical-electrical properties of coconut oil, causing some types of rubber seals to 'open' when diesel would keep them closed. Well, it could be, but it's is difficult to ensure whether this theory is correct. What would be too bad is when this means I cannot utilise coconut oil and it also implies that many other cars would get problems with coconut oil in their diesel blend.
In the period Jul/Aug/Sep I have not been able to run on coconut oil because it solidified in the drums in our yard and because I was away on duty travel. My wife does not mind the trouble I go throug in getting the fuel blends prepared, but she'd rather just fill up at Shell, and I don't blame her for that.
Now it's heating up again (spring is in the air!) and I managed to get my coconut pumped out of the drums again.
This time I tried it without kerosene (see page "what fuel has the coconut hilux used") and to my big surprise, at a blend of 60% coconut oil and 40% diesel the injector pump does not leak.
New theory: perhaps the heated kerosene caused the leaks?
Update on tech problems 2006:
The Hilux continues to run fine. It started more and more difficult with oodles of black clouds and thus I replaced the glow plugs. Of course, the electrical connections and the plastic nuts on top gave way so this turned out into a one-day operation. Nevertheless, with the 'original Japanese' replacements, the Hilux still starts great.
If the coconut oil content is above 10%, we need to glow until the hilux starts beeping to avoid excessive long starting or black smoke. Do not forget in the morning in Fiji these days it is still 25 Deg C.
Fuel filters have been replaced so many times, I lost count. But they actually never blocked on me during the last year. I just try to avoid any issue with my wife getting stuck somewhere. So every 10,000 kms there will be a flashing new filter under the hood. I used the old filter to pre-filter the coconut oil before it goes into the tank.
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