Wrangler L4-150 2.5L VIN P MFI (1993)
Fuel Pressure: Testing and Inspection
Fuel Pressure Test
NOTE: The fuel system employs a vacuum assisted pressure regulator. System fuel pressure should be approximately 214 kPa (31 psi) with the vacuum
line connected to the regulator. With the vacuum line disconnected from the regulator, fuel pressure should be approximately 269 kPa (39 psi). This is
55-69 kPa (8-10 psi) higher.
Fuel Pressure Test
PROCEDURE
1. Connect the 0-414 kPa (0-61 psi) fuel pressure gauge (from Gauge Set 5069) to test port pressure fitting on fuel rail.
2. Remove vacuum line from pressure regulator.
3. Start the vehicle.
4. Note gauge reading. With vacuum line disconnected, fuel pressure should be approximately 269 kPa (39 psi).
5. Connect vacuum line to pressure regulator. Note gauge reading. Fuel pressure should be approximately 214 kPa (31 psi).
6. Fuel pressure should be approximately 55-69 kPa (8-10 psi) higher with vacuum line removed from regulator. If not, inspect pressure regulator
vacuum line for leaks, kinks or blockage.
Fuel Return Line
7. If fuel pressure is low, momentarily pinch shut the hose section of the fuel return line.
CAUTION: Fuel pressure will rise to as much as 95 psi when the fuel return line is pinched shut. Shut engine down immediately after pinching
off fuel return line.
If fuel pressure remains low, inspect the fuel supply line, fuel filter, and fuel rail inlet for blockage. If fuel pressure rises, replace fuel pressure
regulator.
8. If fuel pressure is above specifications, inspect the fuel return line for kinks and blockage.
