Diesel to WVO / SVO Conversion Fuel Starvation

List of possible causes and remedies for hard starting and loss of power

Running SVO puts an added strain on the fuel delivery system. This is primarily due to the increased viscosity of the fuel. Fuel starvation is probably the most common problem you will run into if you are running straight vegetable oil. No matter how much you filter or heat it is never going to be as thin as diesel fuel. Plugged filters and air in the fuel lines are the most common problems. If you are sure that is not the problem then consider the following:

Problem & Solution

Common among these chassis:


Here are some tips for troubleshooting a common fuel starvation problem where you absolutely know for sure your two or three engine compartment filters are clean. It could be that you have something wrong with the fuel tank or with the lift pump. There could be flow restrictions in the fuel tank. The lift pump could be working but not working well. Try troubleshooting in this sequence.

1. Maybe the tank is not venting properly. Try driving the car with the fuel tank cap removed and see if that does make any difference. If so take make certain that the vent line is not plugged. You would need to refer to the factory manual for your car for the location and hose routing of the vent.

2. If that does not help then remove the fuel tank screen. SVO has a wonderful scrubbing action and even though the tank was changed maybe the tank screen is now plugged up. Consider adding our over size outlet screen and hose. 

3. If neither of those make any difference then you should consider replacing the lift pump. If you are operating with heavy thick WVO that has not been thinned with diesel a new lift pump may not be the best solution. We have found that adding an electric boost pump at the back end of the system to help "PUSH" the heavier viscosity fuel up to the engine is a better solution and causes less strain on the engine driven lift pump. We have a complete easy to install boost pump that works great with vegetable oil. NOTE: The picture above shows our boost pump kit installed in a W123 chassis diesel.