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Test A1 - No Start

To prevent replacement of good components, ensure that the following non-EEC related areas are not at fault: fuel quantity and quality, ignition system damage, cracks, moisture, etc., engine mechanical conditions such as bad valves, timing belt, etc. Also included are starter and battery circuit problems.

  1. Starting System. Try to start engine. If engine does not crank, check vehicle starting and charging systems. Ensure fuel pump inertia switch is set (button pushed in). If engine cranks, but does not start or stalls after starting, go to next step.
  2. Checking VREF Signal at TPS. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position Sensor (TPS). Turn key on, leaving engine off (KOEO). Measure voltage at TPS harness connector between VREF and SIGNAL RETURN. See Fig 1 or appropriate wiring diagram. If reading is less than 4 volts or more than 6 volts, go to TEST A3 - REF  . VOLTAGE, step 1). If reading is between 4 and 6 volts, reconnect TPS and go to next step.
    Fig 1: TFI Module Circuit Diagram
    G120713
  3. Checking For Spark At Plugs. Disconnect any spark plug wire. Connect a spark tester between plug wire and engine ground. Crank engine. If spark exists, connect spark plug wire and go to step 12). If no spark, connect spark plug wire and go to next step.
  4. Checking For Spark at Coil. Remove high tension coil wire from distributor and install spark tester. Check for spark while cranking engine. If spark exists, connect coil wire and service or repair TFI ignition system. If no spark exists, connect coil wire and go to next step.
  5. Ignition Ground Continuity. Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Disconnect TFI connector. Measure resistance between test pin 16 of the breakout box and TFI harness connector Ignition Ground circuit. If reading is greater than 5 ohms, repair harness and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
  6. Isolating SPOUT Circuit Fault. Install breakout box and connect TFI connector. Connect ECA to breakout box. Set breakout box switch to "DISTRIBUTOR" position. Try to start vehicle. If vehicle starts, go to step 10). If vehicle does not start, go to next step.
  7. Checking SPOUT Signal. Connect breakout box and ECA. Move breakout box timing switch to "COMPUTED" position. Turn key on with engine off. Set DVOM on 20-volt scale and measure voltage between test pin No. 36 of breakout box and negative battery post while cranking engine. If voltage is between 3 and 6 volts, EEC system is NOT at fault. TFI ignition system should be diagnosed. If voltage is not between 3-6 volts, go to next step.
  8. Checking SPOUT and PIP For Shorts. Turn key off and wait 10 seconds. Install breakout box and disconnect ECA. Disconnect TFI connector. Set DVOM on 200K-ohm scale. For SPOUT circuit, measure resistance between test pin No. 36 (SPOUT) and test pins No. 16, 20, 40, 46, and 60 (short to ground), Nos. 26, 37 and 57 (short to power) and then No. 56 (short to PIP) at the breakout box. For PIP circuit, measure resistance between test pin No. 56 and test pins No. 16, 20, 40, 46, and 60 (short to ground), Nos. 26, 37 and 57 (short to power) and No. 36 (short to SPOUT). If any reading is less than 10K ohms, repair short in harness, reconnect components and repeat QUICK TEST. If engine still does not start, go to next step. If all readings are greater than 10K ohms, go to next step.
  9. Isolating Shorts In Processor. Turn key off and wait 10 seconds. Install breakout box and connect ECA to breakout box. Disconnect TFI. Set DVOM on 200K ohm scale. On SPOUT circuit, measure resistance between test pin No. 36 (SPOUT) and test pins No. 37 and 57 (short to power) and Nos. 40 and 60 (short to ground) at the breakout box. On PIP circuit, measure resistance between test pin No. 56 (PIP) and test pins No. 37 and 57 (short to power) and Nos. 40 and 60 (short to ground) at the breakout box. If any reading is less than 500 ohms, remove breakout box, replace ECA and repeat QUICK TEST. If all readings are greater than 500 ohms, reconnect all components and go to next step.
  10. Checking PIP Signal. With key off, install breakout box. Set DVOM on 20-volt scale. Measure voltage between test pins No. 56 and 16 at breakout box. Crank engine and record reading. If reading is between 3 and 7 volts, remove breakout box, replace ECA and repeat QUICK TEST. If reading is not between 3-7 volts, switch breakout box timing switch to "COMPUTED" position and go to next step.
  11. Continuity of PIP Circuit. Turn key off and wait 10 seconds. Install breakout box and disconnect ECA. Disconnect TFI connector. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 56 at breakout box and TFI connector PIP circuit. If reading is not less than 5 ohms, repair open PIP circuit, remove breakout box and repeat QUICK TEST. If readings is less than 5 ohms, remove breakout box, reconnect all components and see appropriate IGNITION SYSTEM article in ENGINE for further diagnostics.
  12. Verifying SPOUT Signal. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box and connect ECA to breakout box. Switch breakout box timing switch is in "COMPUTED" position. Set DVOM on 20-volt scale. Measure voltage between test pin No. 36 and test pins No. 40 and 60 at breakout box, while cranking engine. If reading is between 3-6 volts, go to next step. If reading is not between 3-6 volts, go to step 8).
    CAUTION: Use safety precautions when working on fuel system. No smoking or open flame. If fuel starts leaking, immediately turn key off.
  13. Fuel Pump Check. Connect pressure gauge to vehicle. Note initial pressure reading. Pressurize fuel system by turning key to "RUN" for one second and note pressure reading. Turn key off, and wait 10 seconds. Repeat sequence 5 times. If pressure increased, go to TEST D19 - SYSTEM CHECK  , step 1). If pressure did not increase, turn key off and go to next step.
  14. Inertia Switch Check. Locate and disconnect fuel pump inertia switch. Set DVOM on 200-ohm scale. Measure resistance of switch. If resistance is greater than 5 ohms, ensure inertia switch is reset. If switch will not reset, replace switch, remove breakout box, reconnect components and repeat quick test. If resistance is less than 5 ohms, go to TEST C2 - INERTIA SWITCH  , step 1)
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