60 gmc charging issues - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**AngryPirate** · 10-22-2016, 07:05 PM

So, I've replaced the battery with an exide agm, had the generator rebuilt and replaced the starter.

If I charge the battery up with a charger, it will start.

If I boost it from another vehicle, it will start.

If I drive it for a while, it doesn't have enough juice to turn over the 305 v6.

Thoughts?

I want to say it's the external voltage regulator, but I'm not sure how to test that theory.

Thanks for any tips or ideas!

shp4man · 10-22-2016, 07:22 PM

Do you have a voltmeter? The charging system test involves the use of a voltmeter, a wiring check and "full fielding" the generator to see if it it makes electricity.

**AngryPirate** · 10-22-2016, 07:24 PM

I do have a voltmeter.
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'63GENIII · 10-23-2016, 12:58 AM

You may need to polarize the generator. I believe its done by briefly touching a jumper wire between the battery terminal and one of the other terminals. Not sure which terminal though. Its been 30 years since Ive had a generator in a truck / car but had them in a few Harleys that I owned. Every time I had the generator out, it had to be polarized or it would not charge.

**AngryPirate** · 10-23-2016, 07:48 AM

Quote:

Originally Posted by '63GENIII

You may need to polarize the generator. I believe its done by briefly touching a jumper wire between the battery terminal and one of the other terminals. Not sure which terminal though. Its been 30 years since Ive had a generator in a truck / car but had them in a few Harleys that I owned. Every time I had the generator out, it had to be polarized or it would not charge.

Interesting. I'll read up on that. Thanks!
Posted via Mobile Device

10-22-2016, 07:05 PM	#1
AngryPirate Senior Member Join Date: Jan 2012 Location: Austin, TX Posts: 564	60 gmc charging issues So, I've replaced the battery with an exide agm, had the generator rebuilt and replaced the starter. If I charge the battery up with a charger, it will start. If I boost it from another vehicle, it will start. If I drive it for a while, it doesn't have enough juice to turn over the 305 v6. Thoughts? I want to say it's the external voltage regulator, but I'm not sure how to test that theory. Thanks for any tips or ideas!

10-22-2016, 07:22 PM	#2
shp4man Registered User Join Date: Oct 2016 Location: San Diego, CA Posts: 557	Re: 60 gmc charging issues Do you have a voltmeter? The charging system test involves the use of a voltmeter, a wiring check and "full fielding" the generator to see if it it makes electricity.

10-22-2016, 07:24 PM	#3
AngryPirate Senior Member Join Date: Jan 2012 Location: Austin, TX Posts: 564	Re: 60 gmc charging issues I do have a voltmeter. Posted via Mobile Device

10-23-2016, 12:58 AM	#4
'63GENIII Registered User Join Date: Sep 2008 Location: San Carlos, Ca. Posts: 3,048	Re: 60 gmc charging issues You may need to polarize the generator. I believe its done by briefly touching a jumper wire between the battery terminal and one of the other terminals. Not sure which terminal though. Its been 30 years since Ive had a generator in a truck / car but had them in a few Harleys that I owned. Every time I had the generator out, it had to be polarized or it would not charge. __________________ Chris '63 k15 long step Vortec 7.4 - L29 Blackbear tune, Five 0 Motorsports injectors, Chris Straub Cam, NV4500, divorced 205 52" front and 63" rear spring swap D44 / 14bff - disc axles Milemarker 9K and 10.5K hydraulic winches 63" & B52 Spring Install http://67-72chevytrucks.com/vboard/s...ng+swap+thread NV4500 Reverse Build Thread http://67-72chevytrucks.com/vboard/s...=reverse+build L29 - 7.4 Vortec Build http://67-72chevytrucks.com/vboard/s...&highlight=L29

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