GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2002 🢒 Century 🢒 Engine 🢒 Engine Controls - 3.1L 🢒 Engine Cranks But Does Not Run

Description

The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks but Does Not Run diagnostic table directs the service technician to the appropriate system diagnosis.

The Engine Cranks but Does Not Run diagnostic table assumes the following:

    • The battery is completely charged. Refer to Battery Inspection/Test in Engine Electrical.
    • The engine cranking speed is within specifications. Refer to Engine Cranks Slowly in Engine Electrical.
    • There is adequate fuel in the fuel tank.

Diagnostic Aids

Inspect for the following conditions:

    • Mass air flow (MAF) is compared to a calculated mass air flow based upon the manifold absolute pressure (MAP), the throttle position (TP), and the engine RPM readings. A skewed or unresponsive MAP sensor at KEY ON will cause the predicted air flow value to be inaccurate. Compare the MAP and the TP sensor value to that of a known good vehicle.
    • Faulty engine coolant temperature (ECT) sensor. Using a scan tool, compare engine coolant temperature with intake air temperature (IAT) on a completely cool engine. The engine coolant temperature should be within 3°C (5°F) of the intake air temperature. If not, refer to DTC P0128 .

For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if the ignition relay is providing the listed fuses with voltage.

    2.

  2. If all the Cylinder Injector Circuit Status parameters display Fault, this indicates a condition with the injector supply voltage circuit.

    3.

  3. This step determines if the fuel pump is operating electrically.

  4. This step determines if the camshaft position (CMP) sensor is functioning properly.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Turn ON the ignition, with the engine OFF.
  2. With a scan tool, observe the DTC information.

Does the scan tool display DTC P0101, P0123, P0230, P0341, P0601, P0602, P1626, P1630, or P1631?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Probe both sides of the following fuses:
    3. • F/PMP
    • ELEK IGN
    • Fuel INJR

Does the test lamp illuminate on at least one side of all the fuses listed?

--

Go to Step 4

Go to Ignition Relay Diagnosis

4

  1. With a scan tool, monitor the Cylinder 1-6 Injector Circuit Status parameter.
  2. Crank the engine.

Do all of the Cylinder Injector Circuit Status parameters display OK?

--

Go to Step 5

Go to Fuel Injector Circuit Diagnosis

5

With a scan tool, command the fuel pump ON.

Does the fuel pump turn ON?

--

Go to Step 6

Go to Fuel Pump Electrical Circuit Diagnosis

6
  1. Turn OFF the ignition.
  2. Disconnect a spark plug wire.
  3. Install the J 26792 Spark Tester to the spark plug wire.
  4. Attempt to start the engine.

Does the J 26792 spark?

--

Go to Step 7

Go to Electronic Ignition (EI) System Diagnosis

7
  1. Turn OFF the ignition.
  2. Install all disconnected components.
  3. Install the J 34730-1A Fuel Pressure Gage. Refer to Fuel System Diagnosis .
  4. Turn ON the ignition, with the engine OFF.
  5. Command the fuel pump ON with a scan tool.

Is the fuel pressure within the specified range when the fuel pump is operating?

358-405 kPa

(52-59 psi)

Go to Step 8

Go to Fuel System Diagnosis

8
  1. Disconnect the fuel injector harness multi-way connector.
  2. Jumper the 3 camshaft position (CMP) sensor circuits between the fuel injector harness multi-way connectors.
  3. Probe the fuel injector control circuits, PCM side of the connector, with a test lamp connected to B+.
  4. Crank the engine.

Does the test lamp blink while cranking the engine?

--

Go to Step 9

Go to DTC P0341

9

Inspect for the following conditions:

    • Collapsed air intake duct
    • Restricted air filter element--Refer to Air Cleaner Assembly Replacement .
    • Spark plugs for being gas or coolant fouled--Refer to Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition.
    • Engine mechanical condition--For example, worn timing chain and gears, low compression--Refer to Symptoms - Engine Mechanical in Engine Mechanical.
    • Restricted exhaust system--Refer to Restricted Exhaust in Engine Exhaust.
    • The engine coolant temperature (ECT) sensor is NOT close to the actual engine temperature. Refer to DTC P0128 .
    • Compare the manifold absolute pressure/barometric pressure (MAP/BARO) parameters to another vehicle. The parameters should be close in value. Refer to Manifold Absolute Pressure Sensor Diagnosis .
    • Throttle position (TP) sensor for being stuck in range--Refer to DTC P0121 .

Did you find and correct the condition?

--

Go to Step 10

Go to Diagnostic Aids

10
  1. Clear the DTCs with a scan tool.
  2. Attempt to start the engine.

Does the engine start and continue to operate?

--

Go to Step 11

Go to Step 2

11
  1. Allow the engine to reach operating temperature.
  2. Observe the DTC information with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK