starting problem

[Littlebubba44]

so i have been having problems starting my 87 k10(it does have a computer if that makes a difference). ok so the truck starts great one time and the next it sounds/feels like the battery is dead. the starter will either click or it will engage but wouldn't roll the motor over. last week i put the charger on it or i could jump it. now to night the truck almost didn't start but got it home and tried to start it again and it wouldn't roll it over so my dad tried jumping me and that would even start it. it goes in streaks for a few days it works then nothing. so the battery is only 4 months old(also switched batteries with my dad to check), the alternator is believed to be good. other than maybe a ground what could it be? i'm stumped right now because ever other time at least jumper cables would start it but tonight the wouldn't. any suggestions that might help before i have to find a ride to school and therapy?

 

[JEBSR]

Have you had the chargind system checked? Is the alt light on? If you have a Gage, what does it read? You said you swapped in a known good battery, so I would check your main POS and Neg cables for a good, clean connection. If they are good I would have the starter tested. It sounds like you may have a bad starter.

 

[habitatxskate]

connectors, ground, charge, and the starter.

 

[Littlebubba44]

I have been out working in the cold for 2 hours on it the cleaned the connections,full charged battery, cleaned/tightened the ground on frame... and it does the same thing. i haven't taken the starter off and tested it yet but the last two times my starter went bad it slowly went and if you hit it right you could get it started but this just randomly dies and will work again with a couple hours of fiddling around in the cold.

 

[habitatxskate]

it could be the starter..try and run a jump to the starter wire itself maybe?..

 

[Blazin'4x4]

My 79 k10s starter did the exact same thing. That is the symptoms of the starter going out that your looking for.

 

[Littlebubba44]

we did run a jump off of the battery and it spun the starter but not engaged the spring.