Waste Vegetable Oil Conversion for Diesel Bus

Step 9 Temperature Sensor and Starting Fuel Pump

This bus starts on diesel or biodiesel when the engine is cold. There is a separate small fuel tank for the starting fuel. I don't have a picture of it. It's a 20 gallon red plastic tank strapped under the bus.

Once the engine and veggie oil have heated up to 170 farenheit this temperature sensor switches to the other fuel pump and the engine runs on veggie oil.
There's a manual fuel selector switch in the cab also. When shutting down the engine they switch back to the starting fuel tank for a few minutes before turning off the engine. That way there's no cold veggie oil in the engine or injection system the next time they start it.

When veggie oil is cool, it can put pressure on the fuel pump, doesn't atomize well, doesn't burn completely, and can leave carbon deposits in the engine.

Also it's too thick for the fuel injection pump to move it. In the former inadequate heatling and filtering system that came with the bus when they bought (which has since been replaced by the one being described). Their injector pump broke and had to be replaced once because the veggie oil going into it wasn't hot enough.