Starter or Alternator-guess which is messed up
 

tonite i go to get some gas for my truck and i put the key in-turn the key-turns over but weakly.tried it again and it wouldnt turn over at all.the battery is 5 months old i replaced it in july so i really doubt its the battery but it is possible.i feel its the starter myself but i want to get a second set of opinions.give me your thoughts and opinions on it.thanks in advance guys

does the starter sound like its trying to turn over at all? click? do the lights dim? does it go completely dead? do the lights/accesories work at all? if it sounds weak sounds to me like a bad battery, there is a chance it might have a bad cell.... i am by no means and expert here, just my observations...

turned the lights on and they all seem to be bright.didnt seem to dim when i cranked it either.all lights and accessories seem to work.last night on my way home my truck stalled out and when i cranked it over it seemed weaker than normal.it could be the battery but i dont know since i replaced it just 5 months ago

ok i went outside to double check.i turned the lights on and to me they seemed to be as bright as they normally are.i turned the key and surprise it started but only stayed running for about 10 seconds...its cold outside and my truck hates cold weather.then i hit the key to try and restart it and nothing.so it may be the battery or it may be the starter or alternator.who knows.anyone have this problem happen to them before.oh yeah the lights didnt go dim during cranking

Check connections for corrosion & make sure all grounds are solid. If everything looks OK, I would pull the starter & take it to the local parts house that can bench test the unit. If it's weak, replace the starter & solenoid as a unit. Put a voltmeter on the battery & see what kind of voltage you have while your at it.

most places that sell batteries can load test it for you. The alternator can be tested by starting the truck and disconnecting the battery. If the truck still runs strong, the alternator is the problem. As fot the starter, they are known to be weak when hot, so if your timing is advanced a bit too much, then when the truck is hot the starter just doesnt work well enough.

(WOOOHOO!! 100 legitimate posts!!.... avatar for me....:) )

J-Spec that method of checking alt output is not definite. One or more of the diodes in the alt can be bad & it will still convert some of the current (usually enough to keep it running). A voltage check would be more accurate.

scoti: sorry,I forgot that part, the voltage should stay at 14.6 right?

I've also heard that if you do this with an internally regulated alternator, you can quickly burn it up. Not sure on this, just something I read somewhere.

But you are right, it used to be if you took the positive battery cable off, and it died, it was good sign the alternator was bad.

May not be the case anymore though.

From what I remember it can damage the diodes, but it's been a long time since I wrenched for a living. Maybe someone else w/more recent experience can add to this post??

100+100=200

Just adding to the post!! hahaahah:p :rolleyes:

Or 5+4=9???? j/k

Hey, that's not adding to the post, it's adding in the post.

Clowns. :)

10,000 comedians are out of work, and you two are trying to be funny. LOL

LOL! :)

Sometimes laughter is the only solution to lifes "problems" :)