Altenator/Regulator modification question. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Sooner1970_K10 · 02-18-2005, 01:28 PM

Long story short my truck has no juice. For the past couple of months I have not driven my truck and have made it a point to go out and let it run for 30 mins or so every other week. At first it was doing fine. Starting up on the first key turn and purring to life. Then slowly it seemed to feel a little sluggish as the winter progressed. A couple of weeks ago I went out and it was dead, dead, dead. I jumped it with my little 02 Honda Civic and let the truck run for an hour or so. If I turn it off and then try to restart it, it starts fine. However if I leave it over night the truck wont start. Is this a battery or altenator problem?

Question: I called to find out the price and availibility of a new altenator and was asked if the trucks regulator was original (external) or had been modified (internal). I have no clue?? Can anyone tell me how I can tell if my truck has been modified? Should I look into replacing both the battery and altenator or just do the battery first? Napa has a new lifetime warrantied altenator for $69 bucks.

Note: I did a basic altenator check (I think) according to what I have heard, you can take a then piece of steel or a steel butter knife and hold it close to the altenator. If the altenator is good it should have a magnetic affect on the knife and pull it to the altenator. If the altenator is bad it will not pull the knife. Can anyone confirm this method? I did try this and the knife was NOT pulled towards the altenator.

**VetteVet** · 02-18-2005, 02:00 PM

sounds like the regulator to me. If it is external it should be mounted on the outside of the left verticle radiator support leg.You tried the blade trick and it didn;t work so that means the alt field isn't excited you may have a draw on the battery too for it to go dead overnight, this could also mean a dead cell. Let's determine what system you have and we'll go from there.try this thread
http://67-72chevytrucks.com/vboard/s...nal+alternator
Vettevet

Americanrider · 02-18-2005, 02:16 PM

Pull the alternator off & take it in for a load test, most parts stores/shops will do the test for free if the have the tester. Same for the battery. It's the only way to find out for sure. Good time to upgrade to a Hi-output Alt from a motor home.

ezernut9mm · 02-18-2005, 02:22 PM

fire it up and disconnect the battery. if it dies the alt. is bad...

Sooner1970_K10 · 02-18-2005, 02:53 PM

Ok, thanks for the info. I went and took a couple of pictures. From reading the other post, I must have an external regulator.

Now, do I replace the regulator, the altenator and the battery or can I eleminate which ones are good or bad? If so, can you tell me a way to test them?

Sooner1970_K10 · 02-18-2005, 03:06 PM

Ok I jumped the truck, got it started. I unplugged the battery and it kept running. That means my altenator is good? Why did the blade test not work? Could it be the regulator? Well I let it run for about 20-30 mins and turned it off. Then I tried to restart and it wouldnt even turnover once. That leads me to believe the problem lies in the battery. Do I need to be concerned with the regulator or altenator?

danho · 02-18-2005, 03:23 PM

Sounds like the battery to me.
Dan.

neonlarry · 02-18-2005, 04:14 PM

After it runs for a while and the battery is charged enough to start the truck disconnect the battery till the next time you want to start it. If the battery is dead its probably a bad battery, if it starts fine you have a short somewhere in your system that needs to be fixed before you go any further.

barn9 · 02-18-2005, 05:02 PM

Sounds like the battery to me also. I'm guessing you have an O'Reilly's in your neck of the woods, and they can test both the battery and alternator. As for your "blade test", leave the knife in the kitchen where it belongs.

If it happens to be an alternator problem, it would be a good time to upgrade to an internally regulated alternator, and get rid of that old voltage regulator. O'Reilly's here carries the adaptor plug (around $10-12) for the newer style internally regulated alternators, which makes for a quick and easy changeover.

dubie · 02-18-2005, 06:11 PM

If you wanted to swap out the alternator for an internally regulated one for more juice, toddtheodd has a great step by step at the link below. I followed it step by step and it worked PERFECT!! now no more pissin around with the external regulator
http://67-72chevytrucks.com/vboard/s....php3?t=119379

SKYGOD · 02-18-2005, 06:26 PM

Go to any parts store or Walmart and get a "trickle" charger. Hook the wires to the battery and it is set up to unplug when you want to drive the truck. They are like $20 bucks at Walmart and up to $50 at other parts houses. They are a blessing when storing a car in cold weather.

02-18-2005, 01:28 PM	#1
Sooner1970_K10 1970 K10, 350, 4spd! Join Date: Jun 2004 Location: Shawnee, Ok Posts: 128	Altenator/Regulator modification question. Long story short my truck has no juice. For the past couple of months I have not driven my truck and have made it a point to go out and let it run for 30 mins or so every other week. At first it was doing fine. Starting up on the first key turn and purring to life. Then slowly it seemed to feel a little sluggish as the winter progressed. A couple of weeks ago I went out and it was dead, dead, dead. I jumped it with my little 02 Honda Civic and let the truck run for an hour or so. If I turn it off and then try to restart it, it starts fine. However if I leave it over night the truck wont start. Is this a battery or altenator problem? Question: I called to find out the price and availibility of a new altenator and was asked if the trucks regulator was original (external) or had been modified (internal). I have no clue?? Can anyone tell me how I can tell if my truck has been modified? Should I look into replacing both the battery and altenator or just do the battery first? Napa has a new lifetime warrantied altenator for $69 bucks. Note: I did a basic altenator check (I think) according to what I have heard, you can take a then piece of steel or a steel butter knife and hold it close to the altenator. If the altenator is good it should have a magnetic affect on the knife and pull it to the altenator. If the altenator is bad it will not pull the knife. Can anyone confirm this method? I did try this and the knife was NOT pulled towards the altenator.

02-18-2005, 02:00 PM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,718	external or internal sounds like the regulator to me. If it is external it should be mounted on the outside of the left verticle radiator support leg.You tried the blade trick and it didn;t work so that means the alt field isn't excited you may have a draw on the battery too for it to go dead overnight, this could also mean a dead cell. Let's determine what system you have and we'll go from there.try this thread http://67-72chevytrucks.com/vboard/s...nal+alternator Vettevet __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative. Last edited by VetteVet; 02-18-2005 at 02:09 PM.

02-18-2005, 02:22 PM	#4
ezernut9mm Registered User Join Date: Feb 2005 Location: kansas city, mo. Posts: 224	fire it up and disconnect the battery. if it dies the alt. is bad... __________________ '06 silverado (daily driver) '02 nissan sentra (wal-mart warrior)

02-18-2005, 02:53 PM	#5
Sooner1970_K10 1970 K10, 350, 4spd! Join Date: Jun 2004 Location: Shawnee, Ok Posts: 128	Ok, thanks for the info. I went and took a couple of pictures. From reading the other post, I must have an external regulator. Now, do I replace the regulator, the altenator and the battery or can I eleminate which ones are good or bad? If so, can you tell me a way to test them? Attached Images

02-18-2005, 03:06 PM	#6
Sooner1970_K10 1970 K10, 350, 4spd! Join Date: Jun 2004 Location: Shawnee, Ok Posts: 128	2nd test Ok I jumped the truck, got it started. I unplugged the battery and it kept running. That means my altenator is good? Why did the blade test not work? Could it be the regulator? Well I let it run for about 20-30 mins and turned it off. Then I tried to restart and it wouldnt even turnover once. That leads me to believe the problem lies in the battery. Do I need to be concerned with the regulator or altenator?

02-18-2005, 02:16 PM	#3
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	Pull the alternator off & take it in for a load test, most parts stores/shops will do the test for free if the have the tester. Same for the battery. It's the only way to find out for sure. Good time to upgrade to a Hi-output Alt from a motor home.

02-18-2005, 03:23 PM	#7
danho Pesemistic Optimist Join Date: Dec 2002 Location: Prineville, Oregon Posts: 227	Sounds like the battery to me. Dan. __________________ 1972 K20 Cheyenne Super Custom Camper- 4" lift & 35's, built TH350 and 355. Daily driver resto in progress. 1999 Yukon Denali- Wife's ride, hands off.

02-18-2005, 04:14 PM	#8
neonlarry Registered User Join Date: Feb 2002 Location: Vacaville, CA Posts: 2,745	After it runs for a while and the battery is charged enough to start the truck disconnect the battery till the next time you want to start it. If the battery is dead its probably a bad battery, if it starts fine you have a short somewhere in your system that needs to be fixed before you go any further. __________________ 70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI

02-18-2005, 05:02 PM	#9
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	Sounds like the battery to me also. I'm guessing you have an O'Reilly's in your neck of the woods, and they can test both the battery and alternator. As for your "blade test", leave the knife in the kitchen where it belongs. If it happens to be an alternator problem, it would be a good time to upgrade to an internally regulated alternator, and get rid of that old voltage regulator. O'Reilly's here carries the adaptor plug (around $10-12) for the newer style internally regulated alternators, which makes for a quick and easy changeover. __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads. Last edited by barn9; 02-18-2005 at 05:07 PM.

02-18-2005, 06:11 PM	#10
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	If you wanted to swap out the alternator for an internally regulated one for more juice, toddtheodd has a great step by step at the link below. I followed it step by step and it worked PERFECT!! now no more pissin around with the external regulator http://67-72chevytrucks.com/vboard/s....php3?t=119379 __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

02-18-2005, 06:26 PM	#11
SKYGOD Registered User Join Date: Feb 2004 Location: SAVANNAH, GEORGIA Posts: 22	Go to any parts store or Walmart and get a "trickle" charger. Hook the wires to the battery and it is set up to unplug when you want to drive the truck. They are like $20 bucks at Walmart and up to $50 at other parts houses. They are a blessing when storing a car in cold weather. __________________ MARK



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