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Test A - No Start

  1. Try to start engine. If engine does not crank, check for excess fuel in cylinders (hydraulic lock). Check the starting and charging systems. If engine cranks, but does not start or else stalls after starting, go to next step.
  2. With key OFF, wait 10 seconds. Set DVOM to 20 volt scale and disconnect the TPS. Turn key ON, leaving engine OFF, and measure voltage between voltage reference (VREF) and signal return at TPS harness connector. If voltage is less than 4.0 volts or greater than 6.0 volts, go to TEST C  . If voltage is between 4.0-6.0 volts, reconnect TP sensor and go to next step.
  3. Disconnect any spark plug wire and connect spark tester between plug wire and ground. Crank engine and check for spark. If spark exists, go to Step 13). If no spark, reconnect spark plug wire and go to next step.
  4. Remove high tension coil wire from distributor and install spark tester. Check for spark while cranking. If spark is produced, service or repair TFI ignition system. If no spark, reconnect coil wire to distributor and go to next step.
  5. Turn key OFF and wait 10 seconds. Install breakout box with timing switch in "Computed" position. Leave ECA disconnected. Set DVOM to 200 ohm scale and disconnect TFI. Measure resistance between test pin 16 and TFI harness connector ignition ground. If 5 or more ohms resistance is measured, repair wiring and run QUICK TEST again. If less than 5 ohms is measured, go to next step.
  6. Connect TFI and ECA. Move timing switch to "Distributor" position on breakout box. Try to start vehicle. If vehicle starts, go to Step 10). If vehicle does not start, go to next step.
  7. Move breakout box timing switch to "Computed" position. Set DVOM to 20 volt scale and measure voltage between test pin 36 and chassis ground while cranking engine. If voltage is between 3.0-6.0 volts, EEC is alright and TFI should be diagnosed. If voltage is more than 6.0 volts or less than 3.0 volts, go to next step.
  8. Turn key OFF and wait 10 seconds. Disconnect ECA and TFI. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 36 and test pins 16, 20, 26, 40, and 60 for short to ground. Measure resistance between test pin 36 and test pins 37 and 57 for short to power. Measure resistance between test pins 36 and 56 for short to PIP. If any reading is less than 10,000 ohms, repair short in harness and try to start vehicle. Repeat QUICK TEST if engine will not start. If all readings are 10,000 ohms or greater, go to next step.
  9. Turn key OFF and wait 10 seconds. Reconnect ECA and leave TFI disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 36 and test pins 37 and 57 for short to power. Measure resistance between test pin 36 and test pins 40 and 60 for short to ground. If any reading is less than 5.0 ohms, replace ECA and repeat QUICK TEST. If all readings are 5.0 ohms or greater, connect TFI and go to next step.
  10. Set DVOM to 20 volt scale. Measure voltage between test pin 56 and test pin 16 while cranking engine. If reading is 3.0-6.0 volts, remove breakout box. Replace ECA and repeat QUICK TEST. If below 3.0 volts or above 6.0 volts, go to next step.
  11. Install breakout box, turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Disconnect TFI and ECA. Measure resistance between test pin 56 and TFI connector on the PIP circuit. If reading is 5 ohms or more, repair open PIP circuit and repeat QUICK TEST. If less than 5 ohms, go to next step.
  12. Disconnect ECA and turn key OFF. Disconnect TFI and set DVOM to 200,000 ohm scale. Measure resistance between test pin 56 and test pins 16, 20, 26, 40, and 60 for short to ground. Measure resistance between test pin 56 and test pins 37 and 57 for short to power. Measure resistance between test pin 56 and test pin 36 for short to spark output (SPOUT). If any reading is lower than 10,000 ohms, repair PIP circuit and repeat QUICK TEST. If all readings are higher than 10,000 ohms, perform TFI diagnosis.
  13. Turn key OFF and wait for 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged, loose, or corroded pins or wires. Repair wiring and connect ECA. Set DVOM to 20 volt scale and make sure breakout box timing switch is set in "Computed" position. Measure voltage between test pin 36 and chassis ground while cranking engine. If between 3.0-6.0 volts, go to next step. If less than 3.0 volts or greater than 6.0 volts, go to step 10) of this test.
    CAUTION: Next 2 steps apply to EFI and CFI models. On all steps involving fuel testing, turn key OFF immediately if any fuel leaks develop. DO NOT  allow any smoking or open flame in area of vehicle being tested.
  14. Disconnect all electrical connections at injectors. Connect pressure gauge to fuel diagnostic valve (if equipped) on fuel rail. Note any initial pressure reading and then pressurize fuel system. (To pressurize system, turn key ON for 1 second, then turn key OFF. Wait 10 seconds. Repeat "ON, OFF, and wait" sequence 5 times. After final 10 second wait, reconnect all injectors.) If pressure reading did not increase, go to next step. If pressure reading increased, go to TEST S  .
  15. With key OFF and fuel pressure gauge hooked up, push button on fuel pump inertia switch to reset it to ON. If switch will not reset to ON, replace inertia switch and repeat step 14). If switch button was already ON, go to TEST V  . Observe pressure gauge as system is pressurized as in step 14). If pressure reading increases, repeat QUICK TEST. If pressure reading does not increase, go to TEST V  .
Fig 1: TFI Module Circuits
G2540
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