How to Check Fuel Pump Pressure
- 1). Remove the negative battery terminal from the battery's negative post with a wrench to prevent the risk of fire.
- 2). Locate the fuel pump's outlet line. Fuel pumps use two fuel lines. One line, called the inlet line, connects the fuel tank to the pump. The other line, called the "outlet" line, connects the fuel pump to the fuel delivery system. Locate this hose by tracing it to the engine.
- 3). Cut through the outlet line with a utility knife to create two separate ends.
- 4). Slide a hose clamp over the cut end of each fuel line.
- 5). Attach the cut fuel lines to the fuel pressure gauge. Either an arrow or the words "IN" and "OUT" will be stamped into the back of the gauge next to two metal fittings. If the gauge features an arrow, the gauge must be installed so that the arrow faces towards the fuel delivery system. Slide the fuel delivery line onto the fitting next to the point of the arrow, and slide the line connected to the fuel pump onto the remaining fitting. If the gauge instead has the words "IN" and "OUT," the fuel line connected to the fuel pump fits into the "IN" fitting, while the end of the cut fuel line slides onto the "OUT" fitting.
- 6). Slide each hose clamp to the end of its line, where the line enters the fuel gauge. Tighten the screw on the hose clamp with a standard screwdriver to secure the lines in place.
- 7). Reconnect the negative battery cable to the battery, then turn the engine on and observe the needle on the fuel gauge to determine the fuel pressure. Fuel pressure is rated in pounds per square inch (psi).
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