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Tim's Auto Repair
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Experience:  Have owned a repair shop for 25 yrs.
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1999 Chevy Suburban K1500 4WD 5.7 Litre (R) Gas engine. Starts

Resolved Question:

1999 Chevy Suburban K1500 4WD 5.7 Litre (R) Gas engine. Starts but immediately stalls.
Submitted: 7 years ago via OnlineAutoRepair.
Category: Chevy
Expert:  Tim's Auto Repair replied 7 years ago.


first.check the fuel presure,,these must have no less then 60psi at all times..even while turning the starter,,the fuel pump may be weak also,check the crank sensormmake sure it is plugged up well,it may also be bad,,,check the fuel presure first


fuel presure Testing and Inspection


Diagnostic Chart
Diagnostic Chart
Diagnostic Chart
Diagnostic Chart
Diagnostic Chart
Diagnostic Chart

Circuit Description

When you turn ON the ignition switch, the Vehicle Control Module (VCM) turns ON the in-tank fuel pump. The pump remains ON as long as the engine is cranking or running and the VCM is receiving reference pulses. If there are no reference pulses, the VCM shuts the fuel pump OFF within 2 seconds after you turn the ON the ignition or if the engine stops.

An electric fuel pump pumps the fuel through an in-line filter to the Central SFI unit. The pump is attached to the fuel level meter assembly inside of the fuel tank. The pump is designed in order to provide fuel at a pressure above the regulated pressure needed by the injectors. The pressure regulator keeps the fuel available to the injector at a regulated pressure. Unused fuel is returned to the fuel tank by a separate line.

Diagnostic Aids

Tools Required


  • J 34730-E Fuel Pressure Gauge.
  • J 34730-1A Fuel Pressure Gauge with J 34730-250 Fuel Pressure Adapter Kit.
  • d 42873-1 3/8 Fuel Feed Pipe Shutoff Valve and the J 42873-2 5/16 Fuel Return Pipe Shutoff Valve.

Test Description

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

  1. Wrap a shop towel around the fuel pressure connection to absorb any small amount of fuel leakage that may occur when installing the fuel pressure gauge. Turn ON the ignition leaving the engine OFF, the fuel pressure should be 415-455 kPa (60-66 psi). This pressure is controlled by a spring pressure within the regulator assembly.
  1. The fuel pressure that continues to fall is caused by one of the following items:
    • The in-tank modular fuel sender is not holding pressure.
    • The fuel pressure regulator valve is leaking.
    • A Central SFI injector is leaking.
    • Fuel line is leaking.
  1. When the engine is idling, the manifold pressure is low (high vacuum) and is applied to the fuel pressure regulator diaphragm. This will offset the spring and result in a lower fuel pressure. This idle pressure will vary somewhat depending on the barometric pressure; however, the pressure at idle should be less indicating the pressure regulator control.
  1. If the fuel pressure is less than 415 kPa (60 psi), it falls into the following 3 areas:
    • The pressure is regulated but less than 415 kPa (60 psi).The amount of fuel reaching the injector is sufficient, but the pressure is too low. The system will run lean, hard starting cold, no start, overall poor performance, and may set a DTC.
    • A restricted flow causing pressure drop-Normally, a vehicle with a fuel pressure of less than 300 kPa (44 psi) at idle is inoperable. However, it the pressure drop occurs only while driving, the engine will normally surge then stop running as the pressure begins to drop rapidly. This is most likely caused by a restricted fuel line or plugged filter.
    • A leaking or contaminated pressure regulator valve or seat interface may not allow the regulated pressure to be achieved.

Notice: Do not allow the fuel pressure to exceed 517 kPa (75 psi). Excessive pressure may damage the fuel pressure regulator.

  1. Restricting the fuel return line allows the fuel pressure to build above regulated pressure. With the battery voltage applied to the fuel pump test terminal, the pressure should rise above 455 kPa (66 psi), as the valve in the return line is partially closed.
Engine Cranks, But Will Not Run


Diagnostic Chart
Enhanced Ignition System

Circuit Description

This table assumes that the battery condition and the engine cranking speed are OK, as well as having adequate fuel in the tank.

Diagnostic Aids

If no trouble is found in the fuel pump circuit or the ignition system and the cause of an Engine Cranks But Will Not Run has not been found, check for the following conditions:


  • Fouled spark plugs
  • An EGR valve stuck open
  • Low fuel pressure.
  • Water or foreign material in the fuel system
  • A grounded Ignition Control (IC) signal circuit may cause a No Stan or a Start then Stall condition
  • Basic engine problem

The Vehicle Control Module (VCM) has integrated IC circuits that are fault protected; therefore, if a circuit has failed, the integrated IC may not be damaged. If that is the case, the IC will keep the circuit open until the fault in the circuit has been corrected.

When the fault has been corrected, reinstall the VCM and check the circuit. Replace the VCM only if the circuit is still inoperative.

Test Description

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

  1. If the signal is over 2.5 volts, the engine may be in the clear flood mode which will cause starting problems.
  2. If the engine coolant sensor is below -30°C, the VCM provides fuel for this extremely cold temperature which will severely flood the engine.
  1. Use the injector test lamp J 34730-350 in order to test the injector circuit. A blinking lamp indicates that the VCM is controlling the injector.
  2. Voltage at the spark plug is checked using the spark plug tester tool J 26792. No spark indicates a basic ignition problem.
  3. This test will determines if there is fuel pressure at the fuel injection unit and holding steady
Description and Operation


The Crankshaft Position (CKP) Sensor is located in the front engine cover and is perpendicular to the crankshaft target wheel. The air gap between the sensor and the wheel is preset and not adjustable. The target wheel has three slots 60°apart and is keyed to the crankshaft. As the target wheel rotates, the slots passing by the sensor create a change in the magnetic field of the sensor which results in an induced voltage pulse. One revolution of the crankshaft results in three pulses (3x signal). Based on these pulses, the VCM is able to determine crankshaft position and engine speed. The VCM then activates the fuel injector and provides a spark to the Distributor. The relation between the crankshaft position sensor and the target wheel is crucial. The sensor must be exactly perpendicular to the target wheel with the correct air gap.

The crankshaft position sensor provides the VCM with crankshaft speed and crankshaft position. The VCM utilizes this information to determine if an engine Misfire is present. The VCM monitors the Crankshaft Position Sensor (CKP) sensor for momentarily drop in crankshaft speed to determine if a misfire is occurring. When the VCM detects a misfire, a Diagnostic Trouble Code (DTC) P0300 will set. The VCM also monitors the CKP sensor signal circuit for malfunctions. The VCM monitors CKP signal and the High and Low resolution signals. The VCM calculates these signals to determine a ratio. When the VCM detects that the ratio is out of normal operating range, the VCM will set a Diagnostic Trouble Code (DTC) P0337 or a DTC P0338.

Crankshaft Position Sensor Replacement


IMPORTANT: The CKP System System Variation Learning Procedure will need to be performed whenever the Crankshaft Position (CKP) sensor is removed or replaced. Refer to CKP System Variation Learn Procedure.



  1. Remove the electrical connector.
  2. Remove the sensor hold down bolt.
  3. Remove the sensor from the timing cover. NOTE : When installing or removing a crankshaft position (CKP) sensor make sure the sensor is fully seated and held stationary in the front cover before torquing the hold down bolt into the front cover. A sensor which is not seated may result in erratic operation and lead to the setting of false codes.
  4. Inspect the sensor O-ring for wear, cracks or leakage. Replace if necessary. Lube the new O-ring with clean engine oil before installing.


NOTE : Make certain that the Crankshaft Position (CKP) sensor mounting surfaces are clean and free of burrs before installing the CKP sensor.

  1. Install the sensor into the timing cover.
  2. Install the sensor hold down bolt. Tighten
    • Tighten the hold down bolt to 8 Nm (71 lb. in.) .
  1. Install the electrical connector.
Customer: replied 7 years ago.

I had replaced the fuel tank and fuel pump and had the battery disconnected. The engine would start and then stall. I let it sit for a day and yesterday, temperature got up to 50 degrees with sunshine. While you were diagnosing the problem, the car started. So I ran it for a while. I appreciate all the info you provided and will "accept" for payment.

The information and charts alone are worth it. Any more info you would like to provide would be appreciated. Again Thanks. - Larry

Expert:  Tim's Auto Repair replied 7 years ago.


when you remove the battery on this may need to reset the passlock..this may have been why it didnt start


PASSLOCK Reprogramming Auto Learn



  • The body control module (BCM) must be programmed with the proper RPO configurations before performing learn procedures. See BCM Programming/RPO Configuration.
  • If replacing the BCM with a GM Service Parts Operations (SPO) replacement part, the module will learn passlock(TM) sensor data code immediately. The existing PCM however, must learn the new fuel continue password XXXXX the BCM is replaced.
  • If replacing a PCM with a GM Service Parts Operations (SPO) replacement part, after programming, these modules will learn the incoming fuel continue password XXXXX upon receipt of a password XXXXX Once a password XXXXX is received, and a password XXXXX XXXXX a learn procedure must be performed to change this password XXXXX A PCM which has been previously installed in another vehicle will have learned the other vehicle's fuel continue password XXXXX will require a learn procedure after programming to learn the current vehicle's password.

Use this procedure after replacing:

  • Passlock(TM) Sensor
  • BCM
  • PCM

30 Minute Re-Learn Procedure

  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to start the engine, then release the key to ON (vehicle will not start).
  3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
  4. Turn OFF the ignition, and wait 5 seconds .
  5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock(TM) Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK). IMPORTANT: The vehicle learns the Passlock(TM) Sensor Data Code and/or password XXXXX the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
  6. Start the engine (the vehicle has now learned the Passlock(TM) Sensor Data Code and/or password).
  7. With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles


Tim's Auto Repair and 5 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.
Thanks - Very Much appreciated. The info you provided is going to help me now and in the future. I will be sure to use your services in the future as I need them. Thanks again - Larry
Expert:  Tim's Auto Repair replied 7 years ago.

you are welcome

thanks for useing justanswer....