GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 Century 🢒 Engine 🢒 Engine Electrical 🢒 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 is compared to a calculated mass air flow based upon the manifold absolute pressure (MAP), throttle position (TP), and engine RPM readings. A skewed or unresponsive MAP sensor at KEY ON will cause the predicted air flow value to be inaccurate. Compare MAP and 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. 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. If all the Cylinder Injector Circuit Status parameters display Fault, this indicates a condition with the injector supply voltage circuit.

    2.

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

Step

Action

Value(s)

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, P0601, P0602, P1626, P1630, or P1631?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Attempt to start the engine.
  2. With a scan tool, monitor the engine RPM Parameter while the engine is cranking.

Does the engine RPM Parameter display cranking RPM?

--

Go to Step 4

Go to Electronic Ignition (EI) System 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 spark tester 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 Gauge. Refer to Fuel System Diagnosis .
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the fuel pump ON.

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

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 MAP/BARO parameters to another vehicle. The parameters should be close in value. Refer to Manifold Absolute Pressure Sensor Diagnosis .
    • TP sensor for being stuck in range. Refer to DTC P0121 .

Did you find and correct the condition?

--

Go to Step 9

Go to Diagnostic Aids

9
  1. With a scan tool, clear the DTCs.
  2. Attempt to start the engine.

Does the engine start and continue to operate?

--

Go to Step 10

Go to Step 2

10
  1. Idle the engine.
  2. Allow the engine to reach operating temperature.
  3. With a scan tool, observe the DTC information.

Are any DTCs displayed?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 11

11

With a scan tool review the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK