Cadillac 23120351 Fuel Tank Fuel Pump Module Kit (W/O Fuel Level Se)

Before you check fuel pump output and pressure in your Cadillac DTS, make sure the tank has enough fuel and release pressure from the fuel system. Pressurize fuel lines through a fuel pressure gauge that can release pressure with a bleeder valve and includes necessary fitting parts for your car. Start the engine but keep your foot off the pedal, and watch the gauge for two seconds as the fuel pump runs. The pressure reading should stay within the right limits. After starting the engine, it should naturally lower fuel pressure by 3 to 10 pounds per square inch. First, connect a vacuum source to the pressure regulator and put 12 to 14 inches of vacuum onto it. If the pressure drops now, find and fix the vacuum problem; if not, replace the regulator. When the fuel pressure is higher than recommended, check if vacuum is connecting to the fuel pressure regulator and inspect for crushed or blocked fuel return hoses. When fuel pressure shows less than the required amount, replace the fuel filter, and limit fuel return flow to test the regulator. When testing is done, let the fuel pressure escape before taking off the needle. To check electrical diagrams, have someone hold the car key in "On" position while you listen at the fuel filler neck for a whirring noise on top of the fuel filler cap. The whirring will confirm the fuel pump is working to pressurize the system. Make sure the fuel pump relay gets power from the battery at its cable while the ignition is OFF, and then again while the PCM is sending current. When no power reaches the relay connector, look into the fuel pump fuse and wires. Watch the relay and the fuel pump connector for voltage while the ignition key is turned ON. Turn power off from the pump and test it alone to see if it works. Also have a look at the oil pressure switch while checking if the fuel pump works after examining the circuit connections.