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Home >> Ford >> 2000 >> Contour SE, 2.5 L, Standard >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Self-Diagnostics - EEC-V (Bi-Fuel) >> System Tests (Bi-Fuel) >> Test Ad: No Start (Alt Fuel Switch Indicator Is On Steady) >> Diagnostic Aids

Diagnostic Aids

Enter this test only when all steps under QUICK TEST have been successfully completed and engine still does not start or if directed here from another test or chart. This test is only intended to diagnose:

NOTE: During bi-fuel diagnostics, intermittent failures are possible. Perform wiggle test and tap lightly on relays during testing. Ensure LPG fuel level is correct before continuing with diagnostics.
    NOTE: Before completing FRPREAB leakdown test, check for external fuel leaks before the compuvalve.

  1. 1) Monitor FRPREAB PID Leakdown
    Turn ignition switch to OFF position. Connect New Generation Star (NGS) scan tool to Data Link Connector (DLC). Using scan tool, access DIAGNOSTIC DATA LINK menu, and select AFCM. Highlight and select PID/DATA MONITOR AND RECORD. Highlight and select FRPREAB PID. Place ALT fuel switch in ALT position. Turn ignition switch to ON position (engine off). Record FRPREAB value. Wait 2 minutes. If FRPREAB value drops by 10 psi, replace compuvalve. If FRPREAB value does not drop by 10 psi, go to next step.

  2. 2) Confirm MAP Sensor Operation

    Disconnect MAP tap assembly from compuvalve. Turn ignition switch to ON position. Using scan tool, access AFCM MAP PID. If MAP PID value is about local barometric pressure, go to next step. If MAP PID value is not about local barometric pressure, replace compuvalve.

  3. 3) Confirm MAP Sensor Operation While Applying Vacuum

    Ensure MAP tap assembly is disconnected from compuvalve. Turn ignition switch to ON position. Using scan tool, access AFCM MAP PID. Apply vacuum to MAP sensor vacuum port of compuvalve. If MAP PID value changes with vacuum applied, go to next step. If MAP PID value does not change with vacuum applied, replace compuvalve.

  4. 4) Check Tach Signal

    Ensure ignition switch is turned to ON position and scan tool is connected. Place ALT fuel switch in GAS position. Start engine. Using scan tool, access AFCM RPM PID. If RPM PID value does not read engine RPM, go to next step. If RPM PID value is engine RPM, go to step  7).

  5. 5) Check Tach Circuits For Opens

    Turn ignition switch to OFF position. On Contour and F350 models, disconnect in-line harness connector C4037. On F150 models, disconnect in-line harness connector C4036. On all models, disconnect PCM 104-pin connector. On Contour and F350 models, measure resistance between PCM connector terminal No. 48 (White/Pink wire on F350 models, White/Black wire on Contour models) and in-line harness female connector C4037 terminal No. 5 (White/Pink wire on F350 models, White/Black wire on Contour models). See Figure and Figure . On F150 models, measure resistance between PCM connector terminal No. 21 and in-line harness female connector C4036 terminal No. 3 (Dark Blue wire). Also, measure resistance between PCM connector terminal No. 22 and in-line harness female connector C4036 terminal No. 4 (Gray wire). See Figure and Figure . If each measurement is less than 5 ohms, go to  CHECK TACH CIRCUITS FOR SHORTS. If any measurement is 5 ohms or more, repair open in affected circuit.

  6. Check Tach Circuits For Shorts

    On Contour and F350 models, measure resistance between in-line harness female connector C4037 terminal No. 5 (White/Pink wire on F350 models, White/Black wire on Contour models) and ground. On F150 models, measure resistance between in-line harness female connector C4036 terminals No. 3 (Dark Blue wire), 4 (Gray wire) and ground. If each measurement is more than 10 k/ohms, go to next step. If any measurement is 10 k/ohms or less, repair short to ground in affected circuit.

  7. 6) Check Compuvalve Harness For Opens

    Disconnect compuvalve harness connector C4025. Ensure in-line harness connector C4036 (on F150) or C4037 (on Contour and F350) is disconnected. On F150 models, measure resistance between compuvalve harness connector C4025 terminal No. 34 (White wire) and in-line harness male connector C4036 terminal No. 3 (White wire). Also measure between compuvalve harness connector C4025 terminal No. 38 (White wire) and in-line harness male connector C4036 terminal No. 4 (White wire). On Contour and F350 models, measure resistance between compuvalve harness connector C4025 terminal No. 27 (White wire) and in-line harness male connector C4037 terminal No. 5 (White wire). If each measurement is less than 5 ohms, replace compuvalve. If any measurement is 5 ohms or more, repair open in affected circuit.

  8. 7) Check Compuvalve Outlet Line For Blockage

    Turn ignition switch to OFF position. Release ALT fuel system pressure. See FUEL SYSTEM VENTING in REMOVAL, OVERHAUL & INSTALLATION - CNG/LPG (BI-FUEL) article. Disconnect compuvalve outlet line. Apply air pressure to compuvalve outlet line. Listen for air escaping from exhaust tailpipe. If air is heard escaping from exhaust tailpipe, go to next step. If no air is heard escaping from exhaust tailpipe, replace compuvalve outlet line. See COMPUVALVE under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - CNG/LPG (BI-FUEL) article.

  9. 8) Check High & Low Flow Injector Circuits For Opens

    Turn ignition switch to OFF position. Ensure compuvalve harness connector C4025 is disconnected. Disconnect in-line harness connectors C4013 and C4014. See Figure and Figure . Use HIGH & LOW FLOW INJECTOR CIRCUIT CHECK  table to measure resistances between in-line harness connectors C4013, C4014 and C4025 and ground. If all measurements are less than 5 ohms, go to  CHECK HIGH & LOW FLOW INJECTOR CIRCUITS FOR SHORT TO GROUND. If any measurement is 5 ohms or more, repair open in affected circuit.
    HIGH & LOW FLOW INJECTOR OPEN CIRCUIT CHECK

    In-Line Connector & Terminal No. Compuvalve Connector Terminal No.
    C4013 (1)
    1 (2) 53
    2 (3) 55
    5 51
    6 49
    7 47
    8 45
    C4014 (4)
    1 19
    2 17
    3 (3) 1
    (1) See Figure.
    (2) F150 and F350 only.
    (3) F150 and F350 LPG only.
    (4) See Figure.

  10. Check High & Low Flow Injector Circuits For Short To Ground

    Ensure ignition switch is turned to OFF position. Ensure in-line harness connectors C4013, C4014 and C4025 are disconnected. Measure resistance between in-line harness connector C4013 terminals No. 1, 2, 5, 6, 7, 8 and ground and between in-line harness connector C4014 terminals No. 1, 2, 3 and ground. See Figure and Figure . If all measurements are more than 10 k/ohms, go to next step. If any measurement is 10 k/ohms or less, repair short to ground in affected circuit.

  11. 9) Check Compuvalve Injector Circuits

    Inspect injector circuits for physical damage. If damaged, repair as necessary. If no damage exists, replace compuvalve.
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