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 MANUALSCHEVROLET1985STEP VAN P20, 4.8 T, AUTOMATIC, 475/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCEIGNITION SYSTEMIGNITION SYSTEM - HEI (FEDERAL)TESTING - COMPONENT TESTSTESTING PRECAUTIONS
1985 Chevrolet Step Van P20, 4.8 T, Automatic, 475/M40
Testing Precautions
1985 Chevrolet Step Van P20, 4.8 T, Automatic, 475/M40SECTION Testing Precautions
The following precautions MUST be observed during testing procedures:
- DO NOT ground tachometer terminal of distributor connector. Damage to the electronic module or ignition coil can result.
- Disconnect ignition switch connector at distributor before making compression checks.
- When using a timing light, connect at plug end of number 1 spark plug wire. DO NOT pierce plug boot.
- Remove spark plug wires, twist boot 1/2 turn and pull on boot (not on wire).
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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.