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 MANUALSCHEVROLET1987HI-CUBE 6.2 J, 400/M40REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 24 (ENGINE CONTROLS - TESTS W/CODES - 6.5L DIESEL)SELF-DIAGNOSTIC SYSTEMDIAGNOSTIC PROCEDUREPRELIMINARY INSPECTION
1987 Chevrolet Hi-Cube 6.2 J, 400/M40
Preliminary Inspection
1987 Chevrolet Hi-Cube 6.2 J, 400/M40SECTION Preliminary Inspection
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
- Check all vacuum hoses for correct routing, restrictions, cuts or other damage. Inspect difficult-to-see vacuum hoses beneath air cleaner assembly and other engine components.
- Inspect all engine compartment wiring for proper connections. Also check wires for pinched or chafed spots, as well as contact with sharp edges or exhaust manifolds.
- The preliminary inspection is very important and should be performed carefully and thoroughly, as it can often fix a problem without requiring further diagnosis.
NOTE:
Begin all diagnosis with DIAGNOSTIC SYSTEM CHECK chart. After any DEC system repair, repeat diagnostic system check.
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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.