2011 Kia Optima SX Turbo, fluctuating voltage, fuel pressure

I have a 2011 Kia Optima SX turbo that blew a high pressure fuel pump 7 months ago. Now fluctuating voltage and pressure

My 2011 Kia Optima SX turbo blew its high pressure fuel pump 7 months ago. Now it is rough starting in the morning (it's winter here).

The fuel pressure fluctuates between 30psi and 3000psi. The alternator voltage also fluctuates between 7 volts and 14 volts.

I had changed the fuel pressure sensor, and was considering changing the low pressure fuel pump in the gas tank when I found the fluctuating alternator voltage. It has 93000 miles on it. Is there any way to know whether it is primary alternator failure, or could this be due to something else? The only other thing that I can think of is that I replaced all of the bulbs with LED bulbs about two years ago, and the license plate bulbs are flashing on and off/failing.

Also, do you think that dielectric grease in a mated pin connector is a terrible idea, or are the old farmers correct, that the pins will displace the grease and make a weatherproof seal?


never buy a GDI kia, they are junk. And don't put grease on computer connectors, they only use milliamps and 5 volts. I would have auto zone load test alt and battery and pray it's one of those though, they do it free