If you have a broken Nissan distributor cap in your ride, you can forget about starting your car. That's because Nissan distributor caps are vital when it comes to ignition operation. And if your cap has melted, then there's no way your plugs will be able to generate the well-timed sparks required to start engine operation. So if you have a busted cap in your ride, your best recourse is to replace it as soon as possible.