LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 89 (Engine Self-Diagnostics - EEC-V - Bi-Fuel) >> System Tests >> Test Ac: No Start - Alt Fuel Switch Indicator Is On, Then Off >> Testing

Test Ac: No Start - Alt Fuel Switch Indicator Is On, Then Off: Testing

WARNING: This page is about a different car, the 2002 Ford Pickup and 2002 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
    CAUTION: Always disconnect bi-fuel relay module power supply 3-pin harness connector C495 before disconnecting or reconnecting compuvalve main harness connector C1294 to avoid damaging compuvalve or connectors. See Figure.

  1. 1) Check For DTCS
    Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access PCM and retrieve any stored DTCs. Using scan tool, access AFCM and record any stored DTCs. If any PCM DTCs are present, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article. If any AFCM DTCs are present, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS  and repair as necessary. If no DTCs are present, go to next step.
    2. NOTE: Ensure EEC system calibration is for current Bi-Fuel code. On LPG equipped vehicles, Engine Coolant Temperature (ECT) must above 20°F (-7°C) or ALT fuel system may default to GAS mode.

  2. 2) Verify No-Start Concern
    Place ALT fuel switch is in ALT position. Attempt to start engine. If engine starts with ALT fuel switch in ALT position, ALT fuel system is operating properly at this time. If concern is intermittent, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - EEC-V - BI-FUEL article. If engine does not start with ALT fuel switch in ALT position, go to next step.
    3. NOTE: Minimum FRPREAB PID values required to illuminate ALT fuel selector switch indicator is 26 psi (LPG) and 96 psi (CNG).

  3. 3) Access AFCM FRPREAB PID
    Connect scan tool to DLC. Using scan tool, access AFCM and select FRPREAB PID from PID/DATA MONITOR & RECORD menu. Turn ignition off, then on. Select FRPREAB PID from PID/DATA MONITOR & RECORD menu and record value. Monitor FRPREAB PID. If FRPREAB PID value is less than 26 psi (LPG) or less than 96 psi (CNG), go to next step. If FRPREAB PID value is 96 psi or more (CNG), or 25 psi or more (LPG), go to step  10).
    4. NOTE: Before beginning leakdown test, check all fuel connections at vaporizer, regulator, and compuvalve for leaks. See REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.

  4. 4) Monitor FRPREAB PID Leakdown
    Ensure scan tool is connected to DLC. Using scan tool, access AFCM and monitor FRPREAB PID from PID/DATA MONITOR & RECORD menu. Turn ignition off, then on. Record FRPREAB PID value at ignition on. Wait 2 minutes. If FRPREAB PID value drops 10 psi or more, go to step  10). If FRPREAB PID drops less than 10 psi, go to next step.
    5. NOTE: For testing purposes, fuel level must be more than 25 percent (LPG) or 900 psi (CNG). Add fuel if necessary. Check service history on LPG fuel filter. Replace LPG fuel filter if scheduled maintenance interval has not been followed.

  5. 5) Check Fuel Level, Tank Valve & Fuel Filter
    On LPG models, close tank valve and then fully open tank valve (open slowly to ensure excess flow valve does not close). Tank valve is located on LPG fuel tank. On CNG models, ensure manual lockoff of solenoid valve is in normal operating position. Solenoid valve is located on CNG fuel tank. For additional information, see LIQUEFIED PETROLEUM GAS FUEL TANK EVACUATING or COMPRESSED NATURAL GAS FUEL TANK EVACUATING under FUEL SYSTEM PRESSURE RELEASE in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article. On all models, turn ignition on. Using scan tool, access AFCM and select FTP PID from PID/DATA MONITOR & RECORD menu. Monitor FTP PID. Proceed as follows:
    • If FTP PID value is less than 900 psi (CNG and LPG), go to next step.
    • If FTP PID value is 900 psi or more (CNG), replace CNG regulator. See FUEL PRESSURE REGULATOR under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.
    • If FTP PID value is 900 psi or more (LPG), start engine in ALT fuel mode to ensure concern is no longer present.
    6. CAUTION: When connecting test light, DO NOT short across terminals as damage to compuvalve may occur.
    NOTE: This circuit is powered from inertia switch. Test light will only illuminate momentarily.

  6. 6) Check Vaporizer Lockoff Solenoid (LPG)/Solenoid Tank Valve (CNG) Signal
    Turn ignition off. Disconnect in-line harness connector C4002 (LPG) or C4125 (CNG). On CNG models, connect a test light between in-line harness connector C4125F terminal "D" (Pink wire) and terminal "F" (Yellow wire). On LPG models, connect a test light between in-line harness connector C4002F terminal "D" and "F" (both White wires). See Figure and Figure . On all models, observe test light and turn ignition on. If test light illuminates momentarily when ignition is turned on, go to next step. If test light does not illuminate when ignition is turned on, go to step  8).
    7. CAUTION: DO NOT bend diode or flex wires more than 30 degrees.

  7. 7) Check Lockoff Solenoid (LPG)/Solenoid Tank Valve (CNG) Coil Resistance
    Turn ignition off. Ensure in-line harness connector C4002 (LPG) or C4125 (CNG) is disconnected. Gently wiggle connection and flex wires around diode splice. Diode is located in harness near connector. Resistance value must remain within one ohm while wires are being flexed and connection wiggled. Proceed as follows:

    1. CNG Models

      Using DVOM, measure resistance between in-line harness connector C4125M terminal "D" (Red/Light Blue wire) and terminal "F" (Yellow wire). See Figure. If resistance is 15-25 ohms, replace mechanically stuck fuel tank solenoid valve. If resistance is not 15-25 ohms, replace fuel tank solenoid valve for internal open circuit. See FUEL TANK SHUTOFF SOLENOID VALVE under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.

    2. LPG Models

      Using DVOM, measure resistance between in-line harness connector C4002M terminal "D" (White wire) and terminal "F" (Yellow wire). See Figure. If resistance is 8-18 ohms, replace mechanically stuck lockoff solenoid. If resistance is not 8-18 ohms, replace lockoff solenoid for internal open circuit. See LOCKOFF SOLENOID under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.
    8. NOTE: This circuit is powered from inertia switch. Test light will only illuminate momentarily.

  8. 8) Check Fuel Pump Intercept Harness
    Turn ignition off. Ensure in-line harness connector C4002 (LPG) or C4125 (CNG) is disconnected. On CNG models, connect a test light between chassis ground and in-line harness connector C4125F terminal "D" (Pink wire). On LPG models, connect a test light between chassis ground and in-line harness connector C4002F terminal "D" (White wire). See Figure and Figure . On all models, observe test light and turn ignition on. If test light illuminates momentarily when ignition is turned on, go to next step. If test light does not illuminate when ignition is turned on, repair or replace circuit between inertia switch and connector C4002 or C4125 as necessary. Start engine in ALT fuel mode to ensure concern is no longer present.
    9. CAUTION: Always disconnect bi-fuel relay module power supply 3-pin harness connector C495 before disconnecting or reconnecting compuvalve main harness connector C1294 to avoid damaging compuvalve or connectors. See Figure.

  9. 9) Check Compuvalve Main Harness
    Turn ignition off. Disconnect bi-fuel relay module power supply harness connector C495. Disconnect compuvalve harness connector C1294 and in-line 8-pin harness connector C406. Ensure compuvalve in-line harness connector C4002 is disconnected. On CNG models, measure resistance of White wire between compuvalve harness connector C1294 terminal No. 3 and in-line harness connector C406M terminal "F". On LPG models, measure resistance of White wire between compuvalve harness connector C1294 terminal No. 3 and in-line harness connector C4002F terminal "F". See Figure, Figure and Figure . If all resistance measurements are less than 5 ohms, go to next step. If any resistance measurement is 5 ohms or more, repair or replace compuvalve main harness as necessary. Reconnect all connectors, connecting bi-fuel relay module power supply connector C495 last. Start engine in ALT fuel mode to ensure concern is no longer present.
    10. CAUTION: DO NOT bend diode or flex wires more than 30 degrees.

  10. 10) Check Lockoff Solenoid (LPG)/Solenoid Tank Valve (CNG) Coil Resistance
    Turn ignition off. Ensure in-line harness connector C4002 (LPG) or C4125 (CNG) is disconnected. Gently wiggle connection and flex wires around diode splice. Diode is located in harness near connector. Resistance value must remain within one ohm while wires are being flexed and connection wiggled. Proceed as follows:

    • CNG Models

      Using DVOM, measure resistance between in-line harness connector C4125M terminal "D" (Red/Light Blue wire) and terminal "F" (Yellow wire). See Figure. If resistance is 15-25 ohms, replace mechanically stuck fuel tank solenoid valve. If resistance is not 15-25 ohms, replace fuel tank solenoid valve for internal open circuit. See FUEL TANK SHUTOFF SOLENOID VALVE under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.

    • LPG Models

      Using DVOM, measure resistance between in-line harness connector C4002M terminal "D" (White wire) and terminal "F" (Yellow wire). See Figure. If resistance is 8-18 ohms, replace mechanically stuck lockoff solenoid. If resistance is not 8-18 ohms, replace lockoff solenoid for internal open circuit. See LOCKOFF SOLENOID under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - F150 PICKUP - BI-FUEL article.
scientia non olet · About LEMON Manuals