Circuit Description
This table assumes that the battery condition and engine cranking speed are OK, and there is adequate fuel in the fuel tank (Main fuel tank if the vehicle is equipped with dual fuel tanks). Use this table on engines using the Model 295 throttle body.
Diagnostic Aids
If you do not find any trouble in the fuel pump circuit or the ignition system and the cause of an Engine Cranks But Will Not Run has not been found, check for:
| • | Fouled spark plugs |
| • | EGR valve stuck open |
| • | Low fuel pressure -- Refer to Fuel System Diagnosis . |
| • | Water or foreign material in the fuel system |
| • | A grounded IC control circuit may cause a No Start or a Start then Stall condition |
| • | Basic engine problem |
| • | IAC stuck closed |
| • | Check the fuel filter (partially plugged) |
Test Description
The numbers below refer to the step numbers on the Diagnostic Table.
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A Malfunction Indicator Lamp (MIL) ON is a basic test which determines if there is a battery feed and an ignition feed to the ECM.
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An ECM problem can cause a No DLC data and Malfunction Indicator Lamp (MIL) Inoperative will diagnose the ECM.
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If the TP sensor is over 2.5 volts the engine may be in the clear flood mode which causes starting problems.
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If the ECT sensor is below -30°C (-22°F), the ECM provides fuel for this extremely cold temperature which will severely flood the engine.
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A no spark indicates a basic ignition problem.
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While cranking the engine there should be no fuel spray with the injectors disconnected.
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A blinking lamp Indicates that the ECM is controlling the injectors.
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This test determines if there is fuel pressure to the injectors.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the On-Board Diagnostic (OBD) System Check? | -- | ||
2 | Was DTC 54 stored in memory? | -- | ||
Turn the ignition ON leaving the engine OFF. Does the MIL turn ON? | -- | |||
Install a scan tool. Does the scan tool display data? | -- | |||
Check the voltage for the Throttle Position (TP) sensor at closed throttle. Is the TP sensor voltage greater than the specified value? | 2.5 V | |||
Check the temperature for the Engine Coolant Temperature (ECT) sensor. Is the ECT below the specified value? | -30°C (-22°F) | |||
7 |
Does the fuel pump run? | 10 seconds | ||
Did a spark occur? | -- | |||
Does the fuel spray or drip from one or both injectors? | -- | |||
10 | Replace the injector seal or the injector. Is the action complete? | -- | -- | |
Does the test lamp blink on both tests? | -- | |||
12 |
Does the fuel spray from both injectors? | -- | Refer to Diagnostic Aids | |
13 | Does the fuel spray from one injector only? | -- | ||
14 | Replace the fuel injector. Is the action complete? | -- | -- | |
Turn the ignition OFF. Install a fuel pressure gauge. Refer to Fuel System Pressure Test . Is the fuel pressure within the specified value for the specific engine? | 179-220 kPa (26-32 psi) | Go to Fuel System Diagnosis | ||
16 | Replace the fuel injectors. Is the action complete? | -- | -- | |
17 |
Does the engine start and continue to run? | -- | ||
18 | Allow the engine to idle until it reaches the normal operating temperature. Are any DTCs stored? | -- | Go to the Applicable DTC Table | System OK |
