When it comes to choosing the right oil for your old fuel injection pump, you should select one that is specifically designed for high-pressure fuel systems. This type of oil has a much higher viscosity than ordinary engine oil and is specifically formulated to protect against wear and tear in modern, high-pressure fuel injection systems. Additionally, because older pumps are prone to leakage, it’s important to choose an oil with a strong sealant quality that can help prevent leaks from damaging other parts of the vehicle. It’s always best to consult your owner's manual or a qualified technician when selecting the ideal oil for your particular make and model of vehicle.