DRIVE GP-FINAL 1953950 - Caterpillar

(5EK) Truck EnginesReference: Service Manual Module; Systems Operation, Testing And Adjusting, 3406E Diesel Truck Engine; SENR5578; Page 69; "Fuel Transfer Pump". Unnecessary replacement of the fuel transfer pump and check valve in the fuel block may have resulted from confusion about what is considered normal 3406E fuel system pressure.
With the engine at operating temperature, typical fuel pressure can vary from 310 kPa (45 psi) at low idle to 448 kPa (65 psi) at rated rpm. The 102-7535 Check Valve is designed to open between 413 and 448 kPa (60 and 65 psi) to control fuel system pressure. The fuel transfer pump contains an internal relief valve designed to open around 620 kPa (90 psi). This valve will not open during normal operation.
Electronic unit injector performance will start to decline when fuel pressure drops below 241 kPa (35 psi). Low power complaints and erratic operation can occur in this situation. Look for plugged fuel filter or air in the fuel lines as possible causes for these complaints before replacing major fuel system components.
Make note of this information in the Reference.