1991 Ford Probe GL, AutomaticFACTORY OEM SERVICE PROCEDURE

Fuel System Pressure Test

  1. Using jumper wire, connect fuel system test connector. See Figure and Figure . Turn ignition on (engine off) to activate fuel pump. Remove fuel pump wiring harness connector. Measure voltage between connector Black/Pink wire (1.8L) or White/Yellow wire (2.2L) and ground.
  2. Voltage should be greater than 10.5 volts. If voltage is less than 10.5 volts, turn ignition off and release fuel system pressure. Remove fuel filter and inspect for restriction or contamination. Replace fuel filter if necessary. If fuel filter is okay, go to step 3).
  3. With fuel pressure released, install fuel pressure gauge between fuel filter and fuel rail with main valve open and drain valve closed. Start engine and run for 10 seconds. Stop engine and wait for 10 seconds. Start engine and run for 10 seconds.
  4. Stop engine and remove vacuum hose from pressure regulator. Check pressure regulator for fuel leakage through diaphragm. If fuel is present, replace pressure regulator. If fuel is not present, start engine and run for 30 seconds. Stop engine and wait 5 MINUTES. If fuel pressure is less than 21 psi, start engine and run for 30 seconds.
  5. Stop engine and wait 5 MINUTES. If fuel pressure is still less than 21 psi, replace pressure regulator. If fuel pressure is greater than 21 psi, remove fuel pressure regulator. Check "O" ring, gasket and mounting surface for excessive wear or damage. See Fig 1 . Repair or replace as necessary. Attach vacuum pump to fuel return line.
  6. Apply 20 in. Hg for 10 seconds. If vacuum drops below 10 in. Hg, replace pressure regulator. If vacuum does not drop below 10 in. Hg, put fuel pressure gauge drain hose into an empty metal container. Using jumper wire, connect fuel system test connector to activate fuel pump. Turn ignition on (engine off) for 10 seconds. Measure fuel volume and compare to specification. See FUEL VOLUME SPECIFICATION  .
  7. If fuel volume is less than specification, service fuel pump inlet screen and repeat fuel volume test. If fuel volume is still less than specification, replace fuel pump. If fuel volume is as specified, jumper test connector test lead and turn ignition on to activate fuel pump. Operate fuel pump for 30 seconds. Observe fuel pressure gauge for 3 MINUTES. If fuel pressure decreases more than 2 psi, replace fuel pump.
FUEL VOLUME SPECIFICATION

Application (1) Ounces (cc)
1.8L 5.5 (167)
2.2L 7.4-12.9 (220-380)
(1) Fuel pump volume after 10 seconds of operation.
Fig 1: Identifying Fuel Pressure Regulator Components
G91I08175Courtesy of FORD MOTOR CO.
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