GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Chevy C Cab/Chassis HD (GMT 400) 🢒 Engine 🢒 Engine Electrical 🢒 Engine Cranks But Does Not Run

Description

This 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.

This diagnostic table assumes the following conditions:

    • The battery is completely charged. Refer to Battery Inspection/Test in Engine Electrical.
    • The 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:

    • The 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 MAP and TP sensor values 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.
        For an intermittent condition, refer to Intermittent Conditions .

Test Description

The number below refers to the step number on the diagnostic table.

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

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 DTCs P0230, P0335, P0336, P0601, P0602, P0604, P0606, P1626, 1631, or P1683?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3
  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 4

Go to Electronic Ignition (EI) System Diagnosis

4

With a scan tool, command the fuel pump ON.

Does the fuel pump turn ON?

--

Go to Step 5

Go to Fuel Pump Electrical Circuit Diagnosis

5
  1. Turn OFF the ignition.
  2. Install the J 34730-1A Fuel Pressure Gage. Refer to Fuel Pressure Gage Installation and Removal .
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the fuel pump ON.

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

384-425 kPa

(55-62 psi)

Go to Step 6

Go to Fuel System Diagnosis

6
  1. Turn OFF the ignition.
  2. Disconnect an injector connector.
  3. Install the J 34730-405 Injector Test Lamp to the injector connector.
  4. Attempt to start the engine.

Does the test lamp blink while the engine is cranking?

--

Go to Step 7

Go to DTC P0200

7

Inspect for the following conditions:

    • Collapsed air intake duct
    • Restricted air filter element--Refer to Air Cleaner Element 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 (worn timing chain and gears, low compression, etc.)--Refer to Symptoms - Engine Mechanical in Engine Mechanical 8.1L.
    • Restricted exhaust system--Refer to Restricted Exhaust in Engine Exhaust.
    • The engine coolant temperature (ECT) sensor is NOT close to the actual engine temperature.
    • Compare MAP/BARO parameters to another vehicle. The parameters should be close in value.

Did you find and correct the condition?

--

Go to Step 8

Go to Diagnostic Aids

8
  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 9

Go to Step 2

9
  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 10

10

With a scan tool, observe 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