Nissan Repair: Car wont start sometimes, volt ohm meter, positive cable

Question
Hello, i have been having a problem more and more with my car.  Sometimes when i drive short distances the car won't start after words, usually when the car is hot.  I asked many people about this but no one could help.  please give me your expertise advice. when i go to start the car, all i hear is the fuel injection turn on and it sounds like a buzzing noise, when i turn the key for it to start, thats all i hear, the engine does not even turn, but when i come back in a few hours in the next day it will start right up when it is cold, could it possibly be the starter, or maybe my key, it has a chip in it and i was wondering if it was fried?

PLEASE HELP.. thank you

Answer
Hi Bart,

Could be the starter but I think you have a bad alternator. The alternator is possibly putting out just enough to leave a low charge in the battery. The battery somewhat recovers after sitting for a bit. Also, there is more drag on a hot engine so the battery may not have enough to fire it. It's not your key. If your chip was fried then it would never start. To test alternator output, start the car and disconnect the positive cable. If it dies, then for sure you need an alternator. If it continues to run, takr a Volt/Ohm meter and connect it from the positive cable to the negative battery terminal. Read the voltage. Now you want to do this test with the alternator under a load, so turn on everything, the lights, a/c, radio, etc... The reading you get shouldn't be under 12.8 and that would be the lowest. If this passes then replace the starter. Sometimes starters will over heat and refuse to work. I personally think it's the alt having just done this same thing with mine.