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HOMESERVICE MANUALSCHEVROLET1987HI-CUBE 6.2 J, 400/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMFUEL INJECTION SYSTEM - 6.2L DIESELADJUSTMENTSTHROTTLE POSITION SWITCH (TPS)
1987 Chevrolet Hi-Cube 6.2 J, 400/M40

Throttle Position Switch (TPS)

1987 Chevrolet Hi-Cube 6.2 J, 400/M40SECTION Throttle Position Switch (TPS)
  1. Loosely assemble throttle position switch to fuel injection pump with throttle lever in closed position. Disconnect throttle position switch connector. Attach an ohmmeter between Ignition (Pink wire) and EGR (Yellow wire) of TPS switch.
  2. Insert proper "switch-closed" Gauge Block (J-33043-A) between gauge boss on injection pump and wide open stop screw on throttle shaft.
    NOTE: Always refer to Emission Control Label for correct gauge block size.
  3. Rotate throttle lever and hold wide open throttle stop screw against gauge block. Rotate TPS until there is continuity between terminals. Hold switch body at this position and tighten mounting bolts to 53 INCH lbs. (6 N.m).
    NOTE: Switch point must be set only while rotating switch body in clockwise direction.
  4. Release throttle lever and allow it to return to idle position. Remove "switch-closed" gauge block and insert "switch-open" gauge block. Rotate throttle lever against "switch-open" gauge block. There should be no continuity between terminals.
  5. If no continuity exists, switch is set properly. However, if there is continuity, then switch must be reset by returning to step 1 and repeating entire procedure. See Fig 1.
Fig 1: Throttle Position Switch Adjustment Rotate clockwise until continuity occurs. Courtesy of General Motors Corp.
G11499
RENDER: 1.0x

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
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  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
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