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Home >> Ford >> 2000 >> Contour SE, 2.0 3, Standard >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (Engine Controls - Removal, Overhaul & Installation - CNG/LPG (Bi-Fuel)) >> Adjustments >> Fuel Rail (Tunable "T")

Fuel Rail (Tunable "T")

WARNING: This page is about a different variant/trim than selected.
  1. Park vehicle on flat surface, set parking brake and place wheel chocks both in front of and behind front wheels. Connect exhaust to a vacuum exhaust system and provide adequate ventilation. Turn ignition switch to OFF position. Place ALT/GAS switch to ALT position. Connect a vacuum gauge to intake manifold vacuum.
  2. Connect New Generation Star (NGS) Scan Tool (418-F048), to vehicle Data Link Connector (DLC). Turn the ignition switch to ON position. Select, monitor, and record Powertrain Control Module (PCM) PIDs; ECT, O2S11 and O2S21. Start and run engine while monitoring ECT PID. Allow engine to warm up until ECT PID reads 190°F (88°C).
    3. WARNING: The following step requires engine to be running, in gear and at high RPM. Ensure parking brake is fully set and wheels are chocked. Use all necessary precautions to avoid personal injury, or property and/or equipment damage.
  3. Select, monitor, and record Alternative Fuel Control Module (AFCM) MAP PID and engine vacuum. Place transmission in Reverse while applying brake pedal then slowly apply pressure to accelerator pedal. Continue to raise engine RPM until AFCM MAP PID reads 7.3 -7.4 psi (.5 kg/cm2 ) and record engine vacuum.
    4. WARNING: Never remove tuning "T" adjustment screws while low pressure fuel lines are pressurized. Use caution when setting adjustment screws. If adjustment screws become dislodged from tuning "T", serious personal injury may result.
    NOTE: Vacuum value will be used in the remaining procedures as "Tuning Point".
  4. Allow engine to return to idle position and place transmission in Park. Locate 2 adjustment screw holes on top of tuning "T" assembly, remove any sealant and access adjustment screws. See Fig 1. Using a screwdriver, position both tuning "T" adjustment screws to their "Neutral" position by turning screws until screw head tops are flush with top of tuning "T" and then turning them clockwise 2 complete turns.
  5. With engine running at idle speed and transmission in Park, select GRAPH on NGS scan tool. Record 10 seconds of data from PCM PIDs O2S11 and O2S21. Retrieve and record signal data and identify which HO2S signal displays longest "High State Time". See Fig 2.
    6. WARNING: The following step requires 2 people. Engine needs to be running in gear, and engine RPM raised. Ensure parking brake is fully set and wheels are chocked. Take all necessary precautions to avoid personal injury, property and/or equipment damage.
  6. Use an assistant seated in driver seat, and repeat steps  3 and  4 . Obtain and hold "Tuning Point" vacuum value. Select GRAPH on NGS and record 10 seconds of data from PCM PIDs O2S11 and O2S21. Allow engine to return to idle, and place transmission in Park. Retrieve and record signal data and identify which HO2S signal displays longest "High State Time" as in step  5. See Fig 2.
  7. Determine which tuning "T" adjustment screw requires adjustment. This screw is the only screw to be adjusted throughout entire tuning "T" adjusting procedure and is determined by the following:
    • PCM PID O2S11 data reflects upstream bank No. 1 HO2S and is adjusted with passenger's side tuning "T" adjustment screw.
    • PCM PID O2S21 data reflects upstream bank No. 2 HO2S and is adjusted with driver's side tuning "T" adjustment screw.

    To reduce PCM PID O2S11 or O2S21 "High State Time", corresponding tuning "T" adjustment screw is turned clockwise, and to increase PCM PID O2S11 or O2S21 "High State Time", tuning "T" adjustment screw is turned counterclockwise.

  8. Turn tuning "T" adjustment screw identified in step  6, one complete turn clockwise (reducing "High State Time") and repeat steps  5 and  6 . Retrieve and compare current graphed PCM PIDs O2S11 and O2S21 data with previous data.
  9. If PCM HO2S PID from previous graphed data continues to have longer "High State Time", repeat step  8. If PCM HO2S PID from previous graphed data now has a shorter "High State Time", turn corresponding tuning "T" adjustment screw counterclockwise 1/2 turn and repeat steps  5 and  6 .
  10. Retrieve and compare current recorded graphed PCM PIDs O2S11 and O2S21 data. If necessary, continue to turn same adjustment screw by 1/4 and 1/8 turn increments, clockwise or counterclockwise as described in step  7 repeating steps  5 and  6 with each adjustment until both HO2S PIDs display equal "High State Time". See Fig 3.
  11. When retrieved PCM PIDs O2S11 and O2S21 display equal "High State Time", alternate fuel system is correctly tuned and no further adjustment is required. Document following information:
    • VIN, date, lead technician and assistant.
    • HO2S bank number adjusted, required number of turns to adjustment screw (to nearest 1/8th turn).

    Turn ignition switch to OFF position and remove vacuum gauge and restore intake vacuum system to normal operating condition.

  12. Paint mark tuning "T" adjustment screw positions and seal access hole with manufacturer's sensor safe sealant. Cover and label adjustment screw cavities indicating alternative fuel system tuning procedure has been performed. Update all necessary vehicle inspection labels and placards.
Fig 1: Identifying Tuning "T" Adjustment Screws
G00018669Courtesy of FORD MOTOR CO.
Fig 2: Identifying HOS2 "High State Time" Signal (Example)
G00018670Courtesy of FORD MOTOR CO.
Fig 3: Identifying Normal HOS2 "High State Time" Signal (Example)
G00018671Courtesy of FORD MOTOR CO.
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