GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Safari - 4WD 🢒 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.
    • There is adequate fuel in the fuel tank.

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

Value(s)

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. With a scan tool, observe the DTC information.

Does the scan tool display DTCs P0230, P0335, P0336, P0601, P0602, P0604 or P1683?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3
  1. Attempt to start the engine.
  2. Monitor the engine speed parameter while the engine is cranking with a scan tool.

Does the engine speed increment?

--

Go to Step 4

Go to Distributor Ignition (DI) System Diagnosis

4

Monitor the ignition 1 signal parameter with a scan tool.

Is the ignition 1 signal parameter at the specified value?

B+

Go to Step 5

Go to Step 10

5

Command the fuel pump ON with a scan tool.

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 Distributor Ignition (DI) System Diagnosis

7
  1. Turn OFF the ignition.
  2. Disconnect an injector connector.
  3. Install the J 34730-375 Injector Test Lamp to an injector connector.
  4. Attempt to start the engine.

Does the test lamp blink while the engine is cranking?

--

Go to Step 8

Go to Fuel Injector Circuit Diagnosis

8
  1. Turn OFF the ignition.
  2. Install the J 34730-1A Fuel Pressure Gage . Refer to Fuel System Diagnosis .
  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?

379-427 kPa

(55-62 psi)

Go to Step 9

Go to Fuel System Diagnosis

9

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, gears and 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 Temperature Versus Resistance .
    • Compare MAP/BARO parameters to another vehicle. The parameters should be close in value. This tests the ability of the MAP to correctly indicate barometric pressure (BARO). The value shown for the MAP sensor varies with altitude. The approximate BARO displayed at or near sea level is 103 kPa.
    • TP sensor for being stuck.

Did you find and correct the condition?

--

Go to Step 13

Go to Intermittent Conditions

10
  1. Test the ignition 1 signal voltage circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. Replace the fuse if necessary.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

11

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections or Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

12

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13
  1. Clear the 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 operate?

--

Go to Step 14

Go to Step 2

14
  1. Observe the Capture Info with a scan tool.
  2. Allow the engine to reach operating temperature.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK