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Home >> GMC >> 2001 >> C3500 HD 6.5 F, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 6.5L - Troubleshooting >> Engine Cranks but Does Not Run >> Test Description

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 6:  This step checks for proper cranking speed (see Diagnostic Aids).
  2. 8:  This step will check the ground wire on the injection pump (wire located on top of pump).
  3. 12:  This step will determine if the injection pump or wiring is at fault.
  1. 13:  This step will determine if the fuel injection control voltage is present by probing at the black/gray 4 wire connector jumper harness instead of at the 6-wire pump connector.
Engine Cranks but Does Not Run

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
1
IMPORTANT: Before clearing DTCs use the Scan Tool Capture Info to record Freeze Frame/Failure Records for reference, as data will be lost when Clear Info function is used.
Did you perform the Diagnostic System Check-Engine Controls?		 - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 Check for proper condition of batteries. Refer to Battery Inspection/Test in Engine Electrical.
Is the condition of the batteries OK?		 - Go to Step 3  Go to Step 22 
3 Check for adequate fuel in the tank.
Is the fuel at an adequate level?		 - Go to Step 4  Go to Step 22 
4 Check the quality of the fuel. Refer to Contaminants-in-Fuel Diagnosis .
Is the fuel quality OK?		 - Go to Step 5  Go to Step 22 
5 Check the glow plug system operation. Refer to Glow Plug System Diagnosis .
Are the glow plugs operating OK?		 - Go to Step 6  Go to Step 22 
6  Check for the proper cranking speed. Refer to Diagnostic Aids.
Is the cranking speed OK?		 - Go to Step 7  Go to Step 22 
7 Check the fuel supply system. Refer to Fuel System Diagnosis .
Does the fuel system operate properly?		 - Go to Step 8  Go to Step 22 
8  Check the injection pump ground wire (located on top of the injection pump).
Is the ground OK?		 - Go to Step 9  Go to Step 22 
9 Install a scan tool.
Does the scan tool display data?		 - Go to Step 10  Go to Scan Tool Does Not Communicate With Class 2 Device in Data Link Communications
10
  1. Monitor the VTD Fuel Disabled parameter on the Powertrain Engine Data 1 list.
  2. Crank the engine.
Does the VTD Fuel Disabled parameter display Active while the engine is being cranked?		 - Go to Diagnostic System Check - Theft Deterrent in Theft Deterrent Go to Step 11 
11
  1. Loosen the injector line at the injector.
  2. Crank the engine.
  3. Repeat the procedure for the remaining injectors.
Is there fuel at each injection line?		 - Injection System is OK Go to Step 12 
12  Disconnect the optical/fuel temperature sensor.
Does the vehicle start?		 - Go to Step 16  Go to Step 13 
13 
  1. Reconnect the optical/fuel temperature sensor.
  2. Disconnect the fuel solenoid driver at the fuel injection pump 4 wire jumper harness.
  3. With DMM connected to ground, probe the fuel injector control circuit (terminal A) at the 4 wire jumper harness connector (PCM side).
  4. Crank the engine.
Is the voltage more than or equal to the specified value?		 1.2 V Go to Step 14  Go to Step 17 
14
  1. Verify the fuel solenoid driver 4 wire jumper harness is still disconnected.
  2. Probe the fuel solenoid closure ground circuit (terminal B) with a test lamp connected to B+ at the harness terminal (PCM side).
Does the test lamp illuminate?		 - Go to Step 15  Go to Step 18 
15
  1. Turn ON the ignition, with the engine OFF.
  2. Verify the fuel solenoid driver 4 wire jumper harness is still disconnected.
  3. Probe the ignition feed circuit (terminal C) at the fuel solenoid 4 wire jumper harness connector (PCM side) with a test lamp connected to ground.
Does the test lamp illuminate?		 - Go to Step 16  Go to Step 20 
16 Replace fuel injection pump. Refer to Fuel Injection Pump Replacement .
Did you complete the replacement?		 - Go to Step 24  -
17 Check the fuel injection control circuit for an open or short to ground between the fuel solenoid driver and the PCM.
Was a problem found?		 - Go to Step 21  Go to Step 19 
18 Check the closure ground circuit for an open between the fuel solenoid driver and the PCM.
Was a problem found?		 - Go to Step 21  Go to Step 19 
19 Inspect the fuel solenoid driver connector and the PCM connector for a proper connection.
Was a problem found?		 - Go to Step 21  Go to Step 23 
20 Repair the open in the ignition 1 voltage circuit.
Did you complete the repair?		 - Go to Step 24  -
21 Repair the circuit as necessary.
Did you complete the repair?		 - Go to Step 24  -
22 Make the appropriate repairs.
Did you complete the repair?		 - Go to Step 24  -
23 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 24  -
24
  1. Using the scan tool, select DTC, Clear Info.
  2. Attempt to start the engine.
Does the engine start and continue to run?		 - Go to Step 25  Go to Step 2 
25 Using the scan tool, select Capture Info, Review Info.
Are any DTCs displayed that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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