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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 13262
Experience:  Have owned a repair shop for 25 yrs.
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I have a 2000 Chevrolet 2000 Silverado 4.3 V6. It wont start

Customer Question

I have a 2000 Chevrolet 2000 Silverado 4.3 V6. It won't start when it rains. It did a have a problem related to the distributor venting, so the vent screen was removed. At that time the plug wires and plugs and cap and rotor were replaced. Two weeks ago a strange starting problem occured. Won't start when it rains. When it is not raining, it starts but idles roughly at first, BUT after a 1/2 mile of driving runs completely smooth. So I replaced the cap and rotor AGAIN (3rd time in 2 years and removed the screens this time). I thought maybe water in gas so added dry gas. Ran Ok until today (still had 1/2 mile issue), now today NO START. I am now wondering if it could be coil? Other things I have read suggested TPS and CPS and MAF sensors but I fail see how rain would affect those? Any help would be appreciated. Thanks
Submitted: 5 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 5 years ago.

hi

you need to check the crank sensor plug.where it plugs into the harness.also check and clean the harness that plugs into the pcm[computer]...also,if it is getting hard to start even when it isnt raining..you may want to check the fuel presure,these must have no less then 60psi at all times

thanks

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General Description

 


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 four slots 60 degrees 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 four pulses (4x 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 CKP sensor and the target wheel is crucial. The sensor must be exactly perpendicular to the target wheel with the correct air gap.

Crankshaft Position (CKP) Sensor Replacement

REMOVAL PROCEDURE

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


 

  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. If the vehicle is equipped with the underbody shield package, then remove the steering linkage shield mounting bolts.

 


 

  1. Remove the steering linkage shield.

 


 

  1. Disconnect the CKP sensor harness connector.

 


 

  1. Remove the CKP sensor mounting bolt.

 


 

  1. Remove the CKP sensor.

INSTALLATION PROCEDURE

IMPORTANT:

  • When installing the CKP sensor, make sure the sensor is fully seated before tightening the mounting bolt. A poorly seated CKP sensor may perform erratically; possibly setting false DTCs.
  • Do not reuse the original O-ring.

 


 

  1. Replace the CKP sensor O-ring.
  2. Lubricate the O-ring with clean engine oil before installing the CKP sensor. IMPORTANT: Make sure the CKP sensor mounting surface is clean and free of burrs.
  3. Install the CKP sensor. NOTE: Refer to Fastener Notice in Service Precautions.

 


 

  1. Install the CKP sensor mounting bolt. Tighten Tighten the CKP sensor mounting bolt to 20 N.m (15 lb ft) .

 


 

  1. Connect the CKP sensor harness connector.

 


 

  1. Install the steering linkage shield.

 


 

  1. Install the steering linkage shield mounting bolts. Tighten Tighten the bolts to 33 N.m (24 lb ft) .
  2. Lower the Vehicle. Refer to Lifting and Jacking the Vehicle .
Testing and Inspection
Vehicle Control Module (VCM)
Component Locations
icon_note_blank.gif Notes Locations View
icon_note_blank.gif Notes Locations View

CIRCUIT DESCRIPTION
When you turn ON the ignition, the vehicle control module Vehicle Control Module (VCM) energizes the fuel pump relay which powers the fuel pump ON. The pump remains ON as long as the engine is cranking or running and the VCM receives reference pulses. If there are no reference pulses, the VCM shuts the fuel pump OFF within 2 seconds after the ignition was switched to the ON position or if the engine stops. The VCM also turns ON the fuel pump for 2 seconds when you turn OFF the ignition.

An electric fuel pump pumps the fuel through an in-line filter to the fuel meter body assembly. The pump attaches to the fuel level sender assembly inside of the fuel tank. The fuel pump provides fuel pressure above what is needed by the fuel injectors. The pressure regulator keeps the fuel available to the injectors at a regulated pressure. Unused fuel returns to the fuel tank by the fuel return pipe.

Diagnostic Chart (Part 1 Of 5)
Diagnostic Chart (Part 2 Of 5)
Diagnostic Chart (Part 3 Of 5)
Diagnostic Chart (Part 4 Of 5)
Diagnostic Chart (Part 5 Of 5)

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

 

  1. When the ignition is ON and the fuel pump is running, the fuel pressure indicated by the fuel pressure gauge should read 414-455 kPa (60-66 psi ). The spring pressure inside the fuel pressure regulator controls the fuel pressure.
  2. A fuel system that drops more than 34 kPa (5 psi ) in 10 minutes has a leak in one or more of the following areas:
    • The fuel pump check valve
    • The fuel pump flex pipe
    • The valve or valve seat within the fuel pressure regulator
    • The fuel injectors
    • A fuel pipe
  1. A fuel system that drops more than 14 kPa (2 psi ) in 10 minutes after being relieved to 69 kPa (10 psi ) indicates a leaking fuel pump check valve.
  2. Fuel pressure that drops-off during acceleration, cruise or hard cornering may cause a lean condition. A lean condition can cause a loss of power, surging, or misfire. You can diagnose a lean condition using a scan tool. If an extremely lean condition occurs, the heated oxygen sensors will stop toggling. The heated oxygen sensor output voltages will drop below 300 mV . The fuel injector pulse width will increase. IMPORTANT: Make sure the fuel system is not operating in the Fuel Cut-Off Mode. This can cause false indications by the scan tool.
  3. When you open the throttle quickly, the manifold pressure increases (low vacuum). The fuel pressure regulator increases the fuel pressure as the engine vacuum drops in order to compensate for engine load.
  1. A rich condition may result from the fuel pressure being above 455 kPa (66 psi ). A rich condition may cause a DTC to set. Driveability conditions associated with rich conditions can include hard starting followed by black smoke and a strong sulfur smell in the exhaust.
  2. This test determines if the high fuel pressure is due to a restricted fuel return pipe or if the high fuel pressure is due to a faulty fuel pressure regulator.
  1. A lean condition may result from the fuel pressure being below 414 kPa (60 psi ). A lean condition may cause a DTC to set. Driveability conditions associated with lean conditions can include hard starting (when the engine is cold), hesitation, poor driveability, lack of power, surging, and misfiring. NOTE : Do not. allow the fuel pressure to exceed 517 kPa (75 psi ). Excessive pressure may damage the fuel pressure regulator.
  2. Restricting the fuel return pipe with the fuel pipe shut-off adapter causes the fuel pressure to rise above the regulated fuel pressure. Using a scan tool to pressurize the fuel system, the fuel pressure should rise above 455 kPa (66 psi ) as the valve on the fuel pipe shut-off adapter connected to the fuel return pipe becomes partially closed.
  1. If the injectors are not grounded, check the spark plug associated with a particular fuel injector for fouling or saturation in order to determine if that particular fuel injector is leaking. If checking the spark plug associated with a particular fuel injector for fouling or saturation does not determine that a particular fuel injector is leaking, use the following procedure:
  1. Remove the fuel meter body assembly. Refer to Fuel Meter Body Assembly Replacement
  2. Reinstall the engine compartment fuel feed and return pipes to the fuel meter body and the chassis fuel pipes. Refer to Fuel Hose/Pipes Replacement (Engine Compartment).
  3. Lift the fuel meter body assembly just enough to leave the fuel injector poppet nozzles in the ports.
  4. Pressurize the fuel system by using the scan tool fuel pump enable.
  5. Visually and physically inspect the fuel injector poppet nozzles for leaks.

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Tim's Auto Repair
Tim's Auto Repair
Mechanic
7881 Satisfied Customers
Have owned a repair shop for 25 yrs.