GM Service Manual Online
For 1990-2009 cars only

Hard Start Symptom

Step

Action

Value(s)

Yes

No

Definition: The engine cranks OK, but does not start for a long time. The engine eventually runs, or may start but then immediately stalls.

1

Did you perform the On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to the Powertrain On Board Diagnostic (OBD) System Check

2

  1. Perform a bulletin search.
  2. If a bulletin that addresses the symptom is present, correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

--

Go to Step 20

Go to Step 3

3

Did you perform a visual/physical check?

--

Go to Step 4

Go to Symptoms for Visual /Physical Check.

4

Check the Engine Coolant Temperature (ECT) sensor for being shifted in the value. With the engine completely cool, compare the Engine Coolant Temperature to the Intake Air Temperature.

Are the ECT and the IAT within the specified value of each other?

+/-3°C (+/-5°F)

Go to Step 8

Go to Step 5

5

  1. Display the engine coolant temperature and note the value with a scan tool.
  2. Check the resistance of the engine coolant temperature sensor.
  3. Refer to Temperature vs Resistance for the resistance specifications.

Does the resistance correspond with the temperature?

--

Go to Step 7

Go to Step 6

6

Replace the ECT sensor.

Is the action complete?

--

Go to Step 20

 

7

Locate and repair the high resistance or the poor connection in the ECT signal circuit or the ECT sensor ground.

Is the action complete?

--

Go to Step 20

 

8

  1. Check for a damaged, plugged, or incorrectly installed crankcase ventilation valve.
  2. If a problem is present, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 9

9

  1. Check for water or alcohol contaminated fuel with a J 39383-A tool. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
  2. If a problem is present, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 10

10

  1. Perform Fuel System Diagnosis .
  2. If a problem is present, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 11

11

Important: Spray the secondary ignition wires with a light mist of water in order to help locate an intermittent problem. The ignition components will arc to ground when a secondary component is malfunctioning. Refer to Ignition System Check .

Visually/physically inspect the secondary ignition wires. Check for the following conditions:

    • Measure the resistance of the spark plug wires. The resistance for cylinders 1, 3, 5 should be within the first range. Cylinders 2, 4, 6 should be within the second range.
    • Check the ignition wires for cross firing.
    • Check the ignition wires arcing to ground.
    • Check the ignition wires for improper routing.

If a problem is present, repair as necessary.

Was a problem found?

7-9K ohms

2-6K ohms

Go to Step 20

Go to Step 12

12

  1. Check for a proper ignition coil output voltage with the spark tester J 26792 (ST 125):
  2. • Clip the spark tester J 26792 to engine ground.
    • Connect one end of a spark plug wire to the spark tester J 26792 ; leave the other end of the spark plug wire connected to the coil being tested.
    • Disconnect the spark plug wire from the other spark plug on the same coil being tested, and ground the wire.
    • Crank the engine while observing the spark tester J 26792 ; a crisp blue spark should be observed.
    • Repeat the above steps for each coil.
  3. If an adequate spark is not present at all of the coils, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 13

13

  1. Remove the spark plugs. Check the spark plugs for the following conditions:
  2. • wet plugs
    • cracks
    • excessive wear
    • improper gap
    • burned electrodes
    • carbon tracking on the insulator
    • heavy deposits. Refer to Ignition System Check

    Notice: Determine the cause of the oil or gas fouled spark plugs in order to avoid damage to the new spark plugs.

  3. If a problem is present, repair the problem as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 14

14

  1. Check the primary connections at the ignition coil assembly. Refer to Electrical Diagnosis in Engine Electrical, and Troubleshooting Procedures for the proper procedure. Also, refer to Checking Terminal Contact in Engine Control Module Diagnosis .
  2. If a problem is present, repair the problem as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 15

15

  1. Check the ignition coils for any cracks or carbon tracking.
  2. If a problem is present, replace the ignition coil assembly.

Was a problem found?

--

Go to Step 20

Go to Step 16

16

  1. Check the ignition coil secondary resistance.
  2. Replace the ignition coil assembly if any of the coils are not within the specified values.

Was a problem found?

10-14 k ohms at 20°C (68°F)

Go to Step 20

Go to Step 17

17

  1. Check the IAC operation.
  2. If a problem is present, repair the problem as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 18

18

  1. Check for the following Engine Mechanical problems. Refer to Engine Mechanical :
  2. • A low compression
    • Sticking valves
    • A hydraulic valve lifter problem
    • Leaking cylinder head gaskets
    • A worn camshaft
    • An incorrect camshaft
    • Incorrect cam timing
    • A damaged timing belt
  3. If a problem is present, repair the problem as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 19

19

  1. Review all of the diagnostic procedures within this table.
  2. If all of the procedures have been completed and no malfunctions have been found, review/inspect the following:
  3. • Perform a visual/physical inspection.
    • The scan tool data
    • The Freeze Frame data.
    • All of the electrical connections within a suspected circuit and/or system
  4. If a problem is present, repair the problem as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 3

20

Operate the vehicle under the same conditions (as closely as possible) as when the original symptom occurred.

Is the original symptom still present?

--

Go to Step 3

The repair is complete. If another driveability symptom exists, refer to Symptoms .