Car won't start without jump

[S_Levatino]

So one day all of a sudden my car wouldn't start so i jumped it and thought nothing of it but it continued to happen so I replaced my alternator cause i knew it was bad (was doing it regardless) and figured it would help but didnt. The car only starts with a jump but always starts first crank and little things like moving my seat will drop the rpms a little and dim the lights so my best guess is a ground or power wire might be loose but I really have no clue where should I check first?

 

[Irish Pride]

You need a new battery. If not done soon you will need another alternator too.

 

[S_Levatino]

You need a new battery. If not done soon you will need another alternator too.

Should of mentioned that but I tried another battery that I know is good same problem

 

[SHOdded]

Which alternator did you use for replacement? I ask because this is an oft-mentioned headache in SHO history. General consensus is either rebuilt Motorcraft or NAPA Gold w lifetime warranty.

 

[Irish Pride]

If it takes a jump and starts/continues to run until it's shut off and then does not start it's because your battery is bad and not charging. It's running off the alternator. If the alternator was bad it would run until the battery ran out of charge and then would not be able to be jumped. Remove the battery and go get it tested.

 

[rubydist]

it could also be bad connections at the battery, or a bad wire from the battery to the alternator.

I have seen battery terminals get a coating of something clear on them such that they look clean but barely allow current to flow. I have also seen battery cables go bad.

So, you need to also check for connection / continuity issues as well as testing the battery.