1987 Ford Bronco that won't start The engine turns but the engine doesn't engage Battery cables have been checked replaced and cleaned Could it be the voltage regulator or something more complicated?

could be anything, no the altanator will not keep it from starting but if it was bad the battery would die after running for a while. first see if your getting spark by removing a plug connect it to the wire, ground it and crank, look for a spark, if you have it then you probably have a fuel problem, or no fuel :( don't rely on your gauge). on way to tell if the pump is working is remove the gas cap and liston when someone else turns the key on, you should hear a hum for a few seconds the it will shut off.