What indicators show a successful cold-start?

• A. Immediate loud banging
• B. No exhaust present
• C. High idle with smoke
• D. Oil pressure steady, fuel pressure stable, correct RPM, exhaust clean with no smoke

Answer: (D)

A successful cold-start means the engine is properly lubricated, fueled, and firing cleanly. The best indicators are that oil pressure comes up quickly and stays steady, confirming lubrication of moving parts; fuel pressure remains stable, showing reliable fuel delivery; the engine settles at the correct idle RPM, indicating proper ignition timing and air–fuel balance at startup; and the exhaust is clean with no smoke, meaning combustion is proceeding normally without burning oil or unburned fuel. Together, these signals demonstrate the engine started smoothly and is operating within normal parameters. Signs like immediate loud banging, no exhaust, or high idle with smoke point to problems (misfire, leakage, or abnormal combustion) and do not reflect a successful cold-start.