Hard Start. Cadillac Concours 1997

For 1990-2009 cars

#### Hard Start Symptom

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately stalls.
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to the Powertrain (OBD) System Check

2

1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found, 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 | Was visual/physical check performed? | -- | Go to Step 4 | Go to Visual /Physical check .
4 | Check Engine Coolant Temperature (ECT) sensor for being shifted in value. With the engine completely cool, compare Engine Coolant Temperature to Intake Air Temperature. Are ECT and IAT within the specified value of each other? | 3°C (5°F) | Go to Step 8 | Go to Step 5

5

1. Using a Scan Tool, display engine coolant temperature and view value.
2. Check resistance of engine coolant temperature sensor.
3. Refer to Engine Coolant Temperature Sensor Temperature vs. Resistance table.

Is resistance value near the resistance for the temperature noted?

--

Go to Step 7

Go to Step 6

6 | Replace the ECT sensor. Is action complete? | -- | Go to Step 20 | --
7 | Locate and repair high resistance or poor connection in the ECT signal circuit or the ECT sensor ground. Is action complete? | -- | Go to Step 20 | --

8

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

Was a problem found?

--

Go to Step 20

Go to Step 9

9

1. Check for water or alcohol contaminated fuel using J 39383-A. Refer to Fuel Check .
2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 10

10

1. Perform Fuel System Pressure Test .
2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 11

11

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

• | Check all Ignition wire resistances; should be less than the specified value.

• | Ignition wires for cross firing.

• | Ignition wires arcing to ground.

• | Ignition wires for improper routing.

• | Spraying the secondary ignition wires with a light mist of water may help locate an intermittent problem. Ignition components will arc to ground when a secondary component is faulty.

2. If a problem is found, repair as necessary.

Was a problem found?

15K ohms

Go to Step 20

Go to Step 12

12

1. Check for proper ignition coil output voltage with spark tester J 26792 (ST 125):

1.1. | Clip the spark tester J 26792 to engine ground.

1.2. | Connect one end of a spark plug wire to the spark tester J 26792; connect the other end of the spark plug wire to the coil being tested.

1.3. | Connect one end of another spark plug wire to the other coil tower; connect the other end of the spark plug wire to ground.

1.4. | Crank the engine while observing the spark tester J 26792; a crisp blue spark should be observed.

1.5. | Repeat the above steps for each coil.

2. If adequate spark is not present at all coils, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 13

13

Important: If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.

1. Remove spark plugs, check for wet plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. Refer to Ignition System .
2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 14

14

1. Check for loose ignition control module ground. Refer to Ignition System.
2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 15

15

1. Remove ignition coils and check the ignition coils for cracks or carbon tracking.
2. If a problem is found, replace affected coil(s) as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 16

16

1. Check ignition coil secondary resistance.
2. Replace any coil(s) which are not within the specified values.

Did any coil(s) require replacement?

5K - 8K ohms

Go to Step 20

Go to Step 17

17

1. Check IAC operation. Perform procedure in DTC P1508 diagnostic table.
2. If a problem is found, repair 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.

• | Low compression,

• | Leaking cylinder head gaskets,

• | Worn or incorrect camshaft

2. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to Step 19

19

1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no malfunctions have been found, review/inspect the following:

• | Visual/physical inspection.

• | Scan Tool data.

• | Freeze Frame data/Failure Records Data.

• | All electrical connections within a suspected circuit and/or system.

3. If a problem is found, repair as necessary.

Was a problem found?

--

Go to Step 20

Go to the Powertrain (OBD) System Check

20 | Operate the vehicle to duplicate conditions present when the original symptom was noted. Is symptom still present? | -- | Go to Step 3 | Repair complete.