help!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**68350** · 06-09-2006, 10:53 PM

I am having troubles with a vehicle. I changed the alternator, voltage regulator, and a new battery, yet it still won't start without being jumper. However, if it's jumped, it runs fine until it is shut off or the negative battery cable is pulled off. the alternator is brand new and was tested good, and the voltage regulator is brand new. anyone have an idea what I can check to see what's wrong? thanks

**VetteVet** · 06-09-2006, 11:22 PM

You may have more than one problem. It sounds like the negative battery cable might not be grounded to the engine or frame good, the starter might have bad brushes or weak coils and when you disconnect the negative battery cable and the engine dies that is a sure sign that the alternator is not charging. The engine should continue to run off the alternator voltage.
Has the battery been fully charged when you try to start it without jumping it? If you have a known good battery in it with a full charge and it won't start without a jump then that indicates a bad ground or a bad starter or solenoid. If it has a weak battery and needs a jump then your charging system is faulty or the wiring is incorrect to the altermator or regulator.

Brainchild · 06-09-2006, 11:41 PM

With it dying when you pull the battery cable,it is not charging.You already knew that though.Make sure all the wires from the back of the alternator are plugged in,and not broken,either in the plastic holder,or in the shield itself,they get pretty brittle after 30+ years.Make sure the regulator is grounded to the core support,and look for bare/broken/burnt wires from the regulator to the firewall,and to the alternator.

Have the new parts tested,new doesn't always mean good,I have gotten a lot of new parts that were worse than the bad ones

**truckdude239** · 06-10-2006, 12:24 AM

i went though 4 voltage regs kept blowing headlights finaly i broke down and did the internal voltage reg swap got my alt. off an 83 chevy k-10 with 350 reman from advance auto for 38 buxs took 30 mins to to the swap http://67-72chevytrucks.com/vboard/s...d.php?t=119379 no problems since

jsbgump · 06-10-2006, 12:27 AM

The starter could be pullin too many amps and causing it not to start.

ivancou · 06-10-2006, 11:11 PM

If it runs after being jumped its running off the battery , further proof is when you disconnect the battery. But without a jump it wont start .
Battery cables .
I had a jeep ,lights/radio worked,no start . Internal corrosian inside the ends of the cable .New cables , end of problem . Not only will they not supply enough power to start the vehicle but it also blocks the power feeding back to the battery . Possible that there is still something amiss in the charging circuit too .Dont assume that just because its new , its ok .
I have a brand new regulator for my C 10 that wont put out enough to charge the battery , had to use the old one and adjust the tension on the one coil inside to get the old one to drop down to 13.8 instead of 17 . The new one has a one year warrenty so now I have to return it . Ivan

06-09-2006, 10:53 PM	#1
68350 Senior Member Join Date: Jan 2002 Location: Williston, ND Posts: 2,999	help!! I am having troubles with a vehicle. I changed the alternator, voltage regulator, and a new battery, yet it still won't start without being jumper. However, if it's jumped, it runs fine until it is shut off or the negative battery cable is pulled off. the alternator is brand new and was tested good, and the voltage regulator is brand new. anyone have an idea what I can check to see what's wrong? thanks __________________ 68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi

06-09-2006, 11:22 PM	#2
VetteVet Msgt USAF Ret Join Date: Jan 2005 Location: Kalamazoo, Michigan Posts: 8,717	Re: help!! You may have more than one problem. It sounds like the negative battery cable might not be grounded to the engine or frame good, the starter might have bad brushes or weak coils and when you disconnect the negative battery cable and the engine dies that is a sure sign that the alternator is not charging. The engine should continue to run off the alternator voltage. Has the battery been fully charged when you try to start it without jumping it? If you have a known good battery in it with a full charge and it won't start without a jump then that indicates a bad ground or a bad starter or solenoid. If it has a weak battery and needs a jump then your charging system is faulty or the wiring is incorrect to the altermator or regulator. __________________ VetteVet metallic green 67 stepside 74 corvette convertible 1965 Harley sportster 1995 Harley wide glide Growing old is hell, but it beats the alternative.

06-09-2006, 11:41 PM	#3
Brainchild Still drivin' a Rat Rod Join Date: Sep 2004 Location: Monett Missouri Posts: 4,925	Re: help!! With it dying when you pull the battery cable,it is not charging.You already knew that though.Make sure all the wires from the back of the alternator are plugged in,and not broken,either in the plastic holder,or in the shield itself,they get pretty brittle after 30+ years.Make sure the regulator is grounded to the core support,and look for bare/broken/burnt wires from the regulator to the firewall,and to the alternator. Have the new parts tested,new doesn't always mean good,I have gotten a lot of new parts that were worse than the bad ones __________________ Rusty Member #13872 Instead of saying.....you are a discomfort in the back of my front.....one should be able to say...... you are a pain in the a$# 71 GMC LWB 49 Chevy 85 Chevy G20 Check out my website

06-10-2006, 12:24 AM	#4
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: help!! i went though 4 voltage regs kept blowing headlights finaly i broke down and did the internal voltage reg swap got my alt. off an 83 chevy k-10 with 350 reman from advance auto for 38 buxs took 30 mins to to the swap http://67-72chevytrucks.com/vboard/s...d.php?t=119379 no problems since __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

06-10-2006, 12:27 AM	#5
jsbgump Gone Fishing Join Date: Aug 2005 Location: Fort Worth, Texas 76135 Posts: 12,361	Re: help!! The starter could be pullin too many amps and causing it not to start. __________________ 68 Chevy Short Fleetside LSX Swap Under Way 3.73 posi 2.5/4 drop Frame of resto has been started 2022 Hyundai Tucson Limited 2019 Chevy Traverse Redline Edition Wifes Ride Build Thread http://67-72chevytrucks.com/vboard/s...=1#post3483616

06-10-2006, 11:11 PM	#6
ivancou New Member Join Date: Apr 2006 Location: Pa Posts: 7	Re: help!! If it runs after being jumped its running off the battery , further proof is when you disconnect the battery. But without a jump it wont start . Battery cables . I had a jeep ,lights/radio worked,no start . Internal corrosian inside the ends of the cable .New cables , end of problem . Not only will they not supply enough power to start the vehicle but it also blocks the power feeding back to the battery . Possible that there is still something amiss in the charging circuit too .Dont assume that just because its new , its ok . I have a brand new regulator for my C 10 that wont put out enough to charge the battery , had to use the old one and adjust the tension on the one coil inside to get the old one to drop down to 13.8 instead of 17 . The new one has a one year warrenty so now I have to return it . Ivan



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