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 MANUALSCHEVROLET1990STEP VAN 5.7 K, AUTOMATIC, 3L80/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEENGINE CONTROLS - SPECIFICATIONSFUEL SYSTEMTHROTTLE POSITION SENSOR (TPS)

1990 Chevrolet Step Van 5.7 K, Automatic, 3L80/M40

Throttle Position Sensor (TPS)

1990 Chevrolet Step Van 5.7 K, Automatic, 3L80/M40SECTION Throttle Position Sensor (TPS)

NOTE: TPS is adjustable only on 2.8L (VIN R) and 6.2L Diesel (VIN C) engines. For further testing, refer to appropriate TESTS W/CODES article.

TPS ADJUSTMENT VOLTAGE

Application

⁽¹⁾⁽²⁾ Voltage

2.8L (VIN R)

.42-.45

6.2L Diesel (VIN U)

1.2

⁽¹⁾	At idle RPM or closed throttle.

⁽²⁾	This is a TPS Voltage Ratio. For adjustment procedure see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

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.