O.t., Need Help!! Please!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1985K10 · 06-21-2004, 10:01 PM

Ok, sorry that its not a truck, but i need help. I just bought a 70 Chevelle, with a 307. When I got it it wasnt charging. I replaced the alternator and regulator both twice. I also changed the battery. We ran tests that would run the alternator unregulated and therefore bypass and eliminate the regulator. Nothing. With 4 different alternators.

The only possible thing I can think of is the battery cables. Is it at all possible that the either or both the cables can be crappy? It cranks over perfect, fast, no problem, so I dont know how it could be the cables.

What do you guys think? I've been working on this for 3 days and I'm really gettin mad!

plumbcut · 06-21-2004, 10:29 PM

I would double check the regulator and related wiring. Sure its possible that its the battery cables but the cables from the battery to the starter shouldnt affect it. As long as there is a good ground (which there should be if its cranking fine)... Did you put a volt meter on the alternator + output? Battery voltage is the SAME with the engine running and when its off? What happens to voltage when you rev it to about 3K rpm?

I think going to a one-wire, internally regulated alternator would be an excellent decision, especially right now. Are you sure that bad alternators werent frying perfectly good regulators, and/or vice versa? Did you ever put a NEW alternator AND regulator in at the same time? If that didnt fix it, I think its the related wiring. Most of that wiring is probably 35 years old....

keep us posted, good luck

plumbcut

1985K10 · 06-21-2004, 11:04 PM

Not running and running the voltage is the same, we checked it at the alternator output, and I changed the alternator and regulator at the same time. Also, following instructions from a Haynes manual, I jumpered the "F" terminal to the bat. terminal, which bypasses the regulator and all wiring, and lets the alternator run at max. output. So i should have gotton like 15V at the battery during this test, and nothing.
My dad has worked on cars for the past 30 years, and him and I are stumped. We tried a couple newer style alternators too, one was known good, and we did the test to bypass all wiring, and nothing. I just ohm checked the battery to alternator, and alternator to block. 0 ohms. I also ohmed out the bat. terminal on the alternator to the pos. bat. terminal, 0 ohms.
I really have no clue anymore....

jimfulco · 06-22-2004, 01:06 AM

Is the idiot light working? Sometimes they won't charge if the idiot light is burned out.

1985K10 · 06-22-2004, 12:19 PM

Yea the light works.
Oh, I posted this in the truck section cuz I THOUGHT id get some help there,not get moved, cuz the two Chevelle forums i tried are like dead.

cdowns · 06-22-2004, 12:43 PM

is there a red wire coming off the +batt terminal like the trucks have? that's where the charge comes from ,i'd trace that out and look for an open circuit

busterwivell · 06-22-2004, 03:13 PM

I'd do the one wire thing, myself. Just one wire from the alternator to the battery. It doesn't get any simpler.

06-21-2004, 10:01 PM	#1
1985K10 Registered User Join Date: Oct 2003 Location: CT Posts: 315	O.t., Need Help!! Please!! Ok, sorry that its not a truck, but i need help. I just bought a 70 Chevelle, with a 307. When I got it it wasnt charging. I replaced the alternator and regulator both twice. I also changed the battery. We ran tests that would run the alternator unregulated and therefore bypass and eliminate the regulator. Nothing. With 4 different alternators. The only possible thing I can think of is the battery cables. Is it at all possible that the either or both the cables can be crappy? It cranks over perfect, fast, no problem, so I dont know how it could be the cables. What do you guys think? I've been working on this for 3 days and I'm really gettin mad! __________________ Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~

06-21-2004, 11:04 PM	#3
1985K10 Registered User Join Date: Oct 2003 Location: CT Posts: 315	Not running and running the voltage is the same, we checked it at the alternator output, and I changed the alternator and regulator at the same time. Also, following instructions from a Haynes manual, I jumpered the "F" terminal to the bat. terminal, which bypasses the regulator and all wiring, and lets the alternator run at max. output. So i should have gotton like 15V at the battery during this test, and nothing. My dad has worked on cars for the past 30 years, and him and I are stumped. We tried a couple newer style alternators too, one was known good, and we did the test to bypass all wiring, and nothing. I just ohm checked the battery to alternator, and alternator to block. 0 ohms. I also ohmed out the bat. terminal on the alternator to the pos. bat. terminal, 0 ohms. I really have no clue anymore.... __________________ Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~

06-22-2004, 12:19 PM	#5
1985K10 Registered User Join Date: Oct 2003 Location: CT Posts: 315	Yea the light works. Oh, I posted this in the truck section cuz I THOUGHT id get some help there,not get moved, cuz the two Chevelle forums i tried are like dead. __________________ Anthony 07 Tahoe LT 70 Chevelle 450HP 383-TH400 77 GMC Royal Sierra~Resto in progress~

06-22-2004, 12:43 PM	#6
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	is there a red wire coming off the +batt terminal like the trucks have? that's where the charge comes from ,i'd trace that out and look for an open circuit __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

06-22-2004, 03:13 PM	#7
busterwivell Registered User Join Date: Jan 2002 Location: Sahuarita, AZ USA Posts: 2,033	I'd do the one wire thing, myself. Just one wire from the alternator to the battery. It doesn't get any simpler. __________________ Bill - Tucson, AZ 47 Chevrolet 2 dr sedan 56 Chevrolet 210 2 dr sedan 66 Chevrolet Malibu 2 dr 4 speed 71 Chevrolet C30 Longhorn 86 Chevrolet Monte Carlo SS (Sold) 01 Chevrolet Tahoe IM - BUSTERWIVE@aol.com

06-21-2004, 10:29 PM	#2
plumbcut california fill Join Date: Apr 2004 Location: Sunny So-Cal Posts: 694	I would double check the regulator and related wiring. Sure its possible that its the battery cables but the cables from the battery to the starter shouldnt affect it. As long as there is a good ground (which there should be if its cranking fine)... Did you put a volt meter on the alternator + output? Battery voltage is the SAME with the engine running and when its off? What happens to voltage when you rev it to about 3K rpm? I think going to a one-wire, internally regulated alternator would be an excellent decision, especially right now. Are you sure that bad alternators werent frying perfectly good regulators, and/or vice versa? Did you ever put a NEW alternator AND regulator in at the same time? If that didnt fix it, I think its the related wiring. Most of that wiring is probably 35 years old.... keep us posted, good luck plumbcut

06-22-2004, 01:06 AM	#4
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	Is the idiot light working? Sometimes they won't charge if the idiot light is burned out.



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