Let's say you have fresh fuel, oil, engine coolant, battery, and the fuel filter is clean. You turn the key and-nothing. Check your battery cables at both ends. Corrosion can rob enough amperage to keep the engine from cranking, and a corroded ground strap at the engine or chassis can often be the culprit. If everything is clean or new, get out your test light and check for power at the starter solenoid terminals.