GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Controls - 8.1L 🢒 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 cranking speed is acceptable. Refer to Engine Cranks Slowly in Engine Electrical.
    • There is adequate fuel in the fuel tanks.

Step

Action

Values

Yes

No

1

Did you perform a 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. Observe the DTC information with a scan tool.

Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604, P0606, or P2610?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3
  1. Turn ON the ignition with the engine OFF.
  2. Probe the PCM 1 fuse with a test lamp that is connected to a good ground.

Does the test lamp illuminate on at least one test point of the fuse?

--

Go to Step 4

Go to Step 10

4

With the ignition switch in the CRANK position, probe the PCM 1 fuse with a test lamp that is connected to a good ground.

Does the test lamp illuminate on at least one test point of the fuse while cranking the engine?

--

Go to Step 5

Go to Step 11

5
  1. Turn ON the ignition with the engine OFF.
  2. Probe both sides of the following fuses with a test lamp connected to ground:
    3. • Eng 2
    • Eng 3

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

--

Go to Step 6

Go to Ignition B in Ignition Relay Diagnosis

6
  1. Turn OFF the ignition.
  2. Disconnect a spark plug wire from a spark plug.
  3. Install the J 26792 Spark Tester to the spark plug wire.
  4. Attach the clamp end of the spark tester to a good engine ground.
  5. Crank the engine while observing the spark tester.
  6. Repeat the test for the remaining cylinders.

Does the spark tester spark on all cylinders?

--

Go to Step 7

Go to Electronic Ignition (EI) System Diagnosis

7

Command the fuel pump ON with a scan tool.

Does the fuel pump turn ON?

--

Go to Step 8

Go to Fuel Pump Electrical Circuit Diagnosis

8
  1. Turn OFF the ignition.
  2. Install the J 34730-1A Fuel Pressure Gage.
  3. Turn ON the ignition, with the engine OFF.
  4. Command the fuel pump ON with a scan tool.

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

384-425 kPa (55-62 psi)

Go to Step 9

Go to Fuel System Diagnosis

9

Inspect for the following conditions:

    • A collapsed air intake duct
    • A restricted air filter element--Refer to Air Cleaner Element Replacement .
    • The spark plugs for being gas or coolant fouled--Refer to Spark Plug Inspection . If the spark plugs are fouled, determine what caused the condition.
    • An engine mechanical condition such as worn timing chain and gears, low compression, etc.--Refer to Symptoms - Engine Mechanical in Engine Mechanical.
    • A 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 Temperature Versus Resistance .
    • Compare MAP/BARO parameters to another vehicle. The parameters should be close in value. Refer to Manifold Absolute Pressure Sensor Diagnosis .

Did you complete the action?

--

Go to Step 13

--

10

Test the ignition 1 voltage circuit between the PCM 1 fuse and the ignition switch for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

11

Test for an intermittent and for a poor connection at the ignition switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

12

Replace the ignition switch. Refer to Ignition and Start Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

--

Go to Step 13

--

13
  1. Clear any DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Attempt to start the engine.

Does the engine start and continue to run?

--

Go to Step 14

Go to Step 2

14
  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