04 mustang electrical problem

[am909]

So I got a problem! 04 mustang 3.9L V6
I got a check engine light for my mass air flow sensor
I cleaned it and I had cleaned up the corrosion on my battery terminals
Now my car starts, but it won’t start after an initial start.
For example, I started the car, drive it to get computer up to speed since it restarted, went to my girlfriends house, turned off the engine, stayed for an hour, was going to go home but the car immediately blacked out when I turned the key to start the car
I was able to get home by unplugging the terminal and plugging it back in. Once I got home, I shut the car off, opened the hood and my door, I tried to start the car again and all the lights blacked out on me again. Not sure what’s causing this problem

 

[wmburns]

I tried to start the car again and all the lights blacked out on me again. Not sure what’s causing this problem

The clue is in the reported symptoms. There simply has to be a weak electrical connection somewhere in the path.

Here's some information on how to perform voltage drop testing. If understood and followed voltage drop testing WILL narrow down where the problem is.

Howto perform charging system voltage drop test

Howto perform charging system voltage drop test

To anyone else reading any of my posts I usually include the line: Today's cars simply will not run right without a strong battery and charging system! Cut corners here at your own risk I'm a big believer in starting with the basics. As such I...

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What confuses most people is they don't fully understand how the voltage drop testing works. Yes it is correct that the leads of the VOM are placed on the same polarity.

Of course the other way to solve your problem is by performing a through visual inspection. Perhaps you don't fully understand the importance of just how tight and clean a high current electrical connection has to be to work.