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Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 12754
Experience:  Have owned a repair shop for 25 yrs.
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2004 s10 blazer 4x4: 4.3 70000 mi.-tach erratic..cuts..runs good

Customer Question

2004 s10 blazer 4x4 4.3 70000 mi.-tach erratic when above 2000 rpm, cuts out, goes crazy,on level runs 70 mph without any trouble. get code po335 clear out runs good until you step on it.
Submitted: 4 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 4 years ago.

hi

you seem to have a bad crank sensor

thanks

P0335

CIRCUIT DESCRIPTION
The Crankshaft Position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor is connected directly to the Powertrain Control (PCM) Module, and consists of the following circuits:

  • The 12-volt reference circuit.
  • The low reference circuit.
  • The CKP sensor signal circuit.

CONDITIONS FOR RUNNING THE DTC

  • DTCs P0101, P0102, P0103, P0341, P0342, or P0343 are not set.
  • The Camshaft Position (CMP) sensor is transitioning.
  • The Mass Air Flow (MAF) is more than 3 g/s in the crank mode.
  • The MAF is more than 5 g/s in the running mode.

CONDITIONS FOR SETTING THE DTC
The PCM determines no signal from the CKP sensor for more than 3 seconds .

ACTION TAKEN WHEN THE DTC SETS

  • The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC

  • The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  • Use a scan tool in order to clear the MIL and the DTC.

DIAGNOSTIC AIDS
The following conditions may cause this DTC to set:

  • Poor connection or poor terminal tension at the sensor-Refer to Testing for Intermittent and Poor Connections in Diagrams.
  • Crankshaft reluctor wheel damage or improper installation
  • Excessive air gap between the CKP sensor and the reluctor wheel
  • The engine running out of fuel
  • Foreign material passing between the sensor and the reluctor wheel

Excess crankshaft end play causes the CKP sensor reluctor wheel to move out of alignment with the CKP sensor. This could result in any one of the following:

  • A no start
  • A start and stall
  • Erratic performance

For an intermittent, Refer to Intermittent Conditions. See: Symptom Related Diagnostic Procedures\Intermittent Conditions

TEST DESCRIPTION

Steps 1-9
Steps 10-16
The numbers below refer to the step numbers on the diagnostic table.

 

  1. This step determines if the fault is present.
  1. This step simulates a CKP sensr signal to the PCM. If the PCM receives the signal, the fuel pump will operate for about two seconds .
  1. The CKP system variation learn procedure must be performed anytime the relationship between the CKP sensor and the CKP reluctor wheel is changed.
  2. The CKP system variation learn procedure must be performed anytime the relationship between the CKP sensor and the CKP reluctor wheel is changed.
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 .
Customer: replied 4 years ago.
I had crankshaft sensor replaced
Expert:  Tim's Auto Repair replied 4 years ago.

ok

lets check the fuel presure..these must have no less then 60psi at any time...these fuel pumps will get weak sometimes and do this

thanks

Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 12754
Experience: Have owned a repair shop for 25 yrs.
Tim's Auto Repair and 5 other Chevy Specialists are ready to help you
Customer: replied 4 years ago.
My man said it is not the fuel pump as it willcut out standing stil and revving engine
Expert:  Tim's Auto Repair replied 4 years ago.

this dont prove anything...you needto put a gage on it

thanks

Customer: replied 4 years ago.

My man put guage on-read 60 psi-?

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