Golf won't turn over, but boosts without issue.

[Kjonus]

So I'll try to explain this the best that I can as it's never happen to me with the car. The car will be operating fine without issue for 99% of the time, she'll turn it of after a drive and when she goes to start it the car won't turn over, she can get a boost and the car will start fine. This first happened during the colder part of the winter so I put it up to a 8 year old battery which was getting weak. Battery was replaced and seemed to fix the issue, fast forward 5 months and now its happening again. The voltage output of the alternator seems to be normal, she tells me that there is no lights that come on the dash before this happens. There is a dash light for the alternator if there is low voltage output from the alternator, or if charging has failed. Could it be an alternator that is starting to fail, I don't see it being a starter as it starts fine off of another car, I've seen on youtube a video about an alternator fuse. Anyone have anything thoughts on where to start.

[BaggedGLI]

Re: Golf won't turn over, but boosts without issue.

What kind of battery? Have seen issues with broken plates in the battery.

[Kjonus]

Re: Golf won't turn over, but boosts without issue.

What kind of battery? Have seen issues with broken plates in the battery.

Kirkland battery from Costco

[Kjonus]

Re: Golf won't turn over, but boosts without issue.

Alright so here's some of the troubleshooting numbers that I got. With the car idling the voltage is sitting at 13.46 and when the car is brought to 2500 rpms it reaches 13.71 with little load, this seems low to me. With lights/ac/stereo on at idle voltage read 12.83 volts and at 2500 rpm 12.93. Do these numbers seem low to you guys, seems a little bit low to me.

[syncrovan]

Re: Golf won't turn over, but boosts without issue.

Is it possible to have the battery fully charged overnight? Number seems low when you apply a load but again, with a battery fully discharged it doesn't help to get the full picture unless you have access to a Ampmeter (clampmeter) to know how much current you are getting out of the alternator.
If you are in the SE or willing to pass by, I have one to test your alternator output.

[VagWrench]

Re: Golf won't turn over, but boosts without issue.

When the alt is charging it should be high 13’s and even can be in the 14v range. If voltage is dropping into the 12’s then the voltage regulator or alt os failing.


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