I was washing the car and went to start it and thought it slow cranked it seemed. then went to restart after drying and it wouldnt. (lights and radio were on while drying) maybe 10 mins.

came back and it barely started and worked fine. checked voltage and its 15 volts.

i know alternators fail 2 ways. 1. Completely dead 2. Overvolting

either bad battery or 15 volts is too much.

opinions?

oh and i got home shut off for few mins and came back it started right up

 

Battery is probably on the way out,have it load tested.

 

alt is prob going out... id still check batt just in case bc its so much easier to replace

 

hmmm...ill have them tested tomorrow

 

id bet its your battery. if the car is hard to start you likely have a cell going bad, it will suck a lot of current trying to keep it charged to the alternator has to overwork and itll often see higher than normal voltage.

try this: start the car and while its running unhook the negative battery cable, then check the voltage between the voltage. if it goes back to normal, you know whats causing the issue.

 

ok cool

 

what ended up being the issue? i'm having the same problem but i replaced my battery at the beginning of this year, so i was leaning more towards the alternator.i have a system in my car and have noticed the lights flicker while i'm stopped and while i'm driving as well.

 

battery tested at 250 cold crank amps...its rated for 590. Time for a new battery.

i think the problem is i cant leave a load while its not charging.

 

ok...heres the rule of thum on batteries....you should have the car where it WILL NOT start but crank ONLY....take a digital multimeter and hook up the leads on the battery....crank for 15 sec and if the voltage drops BELOW 10.6 volts then the battery is bad....DONT DISCONNECT the battery while the car is running...you could have a surge and screw up the ECU.....also....how old is the battery....any extra loads on the car....Ive had the stock stereo going while it was charging my iphone...and I killed my battery....but that was on for like 3 hrs...if your alternator was @ 15V....its ok...its a lil high...but normal alternators run around 14.2-14.6 volts...depending whats needed while its running and the charge state of the battery or how hot or cold it is....also....where did you get the 15 volts from...if you used a DMM..what brand....some brands are no that accurate...

 

^^ bingo the disconnect the alt and see what happens works but its not really a good idea especially with newer cars. some old clunker maybe but that's about it. our cars start at 14.4 then drop to 13.8 for economy or whatever reason gm decided

 

Nhanson or mrgrinch,

I understand that a trip to the dealership may not be your plan of attack on the situations you're describing with your vehicles. If, however, you do decide to work with a dealership towards a diagnosis, I'm happy to be of assistance.

Enjoy the last few bits of 2011!
Sarah
GM Customer Service

 

I used a voltmeter. I'll check crank volts sometime

 

Definitely the battery. Voltage dropped to 14.5