Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1984VALUE VAN P3500, 6.2 J, AUTOMATIC, 475/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEADJUSTMENTTUNE-UP - 5.7L V8 VIN [L]THROTTLE POSITION SENSOR (TPS) ADJUSTMENT
1984 GMC Value Van P3500, 6.2 J, Automatic, 475/M40
Throttle Position Sensor (TPS) Adjustment
1984 GMC Value Van P3500, 6.2 J, Automatic, 475/M40SECTION Throttle Position Sensor (TPS) Adjustment
NOTE:
This procedure only applies to California models. DO NOT
use for Federal vehicles as they don't have a TPS
- DO NOT readjust the TPS unless the TPS is not adjusted correctly or it is necessary to replace the air horn assembly, float bowl, TPS sensor or TPS adjustment screw.
- Using a 5/64" drill bit, drill a 1/16" to 1/8" deep hole in aluminum plug covering TPS adjustment screw. Use care not to damage screw head. See Fig 1 .
- Start a No. 8 1/2" long self-tapping screw in drilled hole turning screw in only far enough to ensure good thread engagement. Using a screw driver between screw head and air horn, pry out plug.
- Using tool (J-28696), remove TPS adjustment screw. Connect digital voltmeter from TPS connector center terminal (B) to bottom terminal (C).
- Turn ignition on, engine stopped, and A/C off. Install TPS adjustment screw to obtain specified TPS voltage.
- Install new plug in air horn. If new plug not available, use Delco Threadlock Adhesive X-10 on screw threads. Adjust voltage, as in step 5).
TPS VOLTAGE ADJUSTMENT
| Engine | Voltage |
|---|---|
| TPS | .41V |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.