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 MANUALSCHEVROLET1983CHEVELLE/MALIBU V8-305 5.0LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSBAROMETRIC PRESSURE SENSORTESTING AND INSPECTION
1983 Chevrolet Chevelle/Malibu V8-305 5.0L
Barometric Pressure Sensor: Testing and Inspection
1983 Chevrolet Chevelle/Malibu V8-305 5.0LSECTION Testing and Inspection
Fig. 008 - Chart C-1D Map and Baro Output Check:
NOTE: MAP and BARO sensors are essentially the same device--one--MAP--measures the difference between pressure in the manifold and atmospheric pressure, and the other--BARO--measures atmospheric pressure.
1. Check that sensor voltage is highest when manifold pressure is highest--output normally is in the middle range for specific altitudes.
- Low voltage increases spark advance.
- High voltage decreases spark advance.
2. Check to see if the rate of change of the output VS change in pressure is correct--normal change would be about the middle of the range listed.
- The voltage should change as soon as the vacuum is changed.
- If it doesn't, it could result in detonation or a sag on acceleration which could also be caused by fuel or a restriction in the hose to the sensor.
RENDER: 1.0x
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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.