wireing shorttage or alternator problem?

quadracer · 09-30-2005, 08:16 PM

I have a 1986 GMC stepside.
The guy that had it before me put a 350 5.7 liter in it.(origianally 5.0 liter), and the wiring on it isnt too hot either.

my question is, could it be possible, the idiot that did this before me wired the alternator wrong?

for instance, bought a brand new battery(die hard), started and ran fine for about 4 days. Then i started to notice when i started it, it sounded like the battery was getting close to dead. Another 2 days, dead, won't start.

So i recharged the battery, ran the short test, which is if there you disconnect the - termenal on the battery, and hit it against the - stub on the battery, if it is a small spark, then there is no short.

Small spark, so there is no short.

so my theory is, is it possible that someone hooked the alternator up wrong, and instead of recharging the battery when the motor is running, the alternator isn't recharging the battery, instead it is just running the truck.

i mean, starting the truck every now and then will slowly drain the battery if it isnt getting recharged by the alternator???? how can i test this????????????

thank you for helping me.

Quadracer

bigmudr · 09-30-2005, 08:52 PM

first, i doubt the alternator is wired wrong. a battery running by itself without the alternator wont even last 1 day, let alone 4. most will only run for a couple of hours tops. on an alternator, there is a power in and a power out. some have external grounds but most are case grounded. its really hard to screw one up. it is possible that the alternator is going bad, though, and just not recharging everything like it should. this kinda sounds like it may be the problem as the battery life shortened from 4 days to under 2. i would have your alternator checked out by a pro to be sure. too many people pretend to know what they're talking about. while some do, most don't. (just to be clear, i am a gm technician, but i will admit if i don't know something. nobody knows everything)

as for your battery test, unless the battery is completely dead, there will always be a spark. that spark is just voltage jumping the air gap when you get close enough to the battery and again as you start to pull away from contact.

sorry for the long answer but i hope that helps you out.

chevyguy · 10-01-2005, 12:12 AM

Flag on the field. If there is nothing drawing power then there shouldnt ba a spark when you connect the battery. To check alternator output simply start it and do a voltage check at the battery should read about 13 volts. As far a wiring it wrong the 305 and the 350 use the same alternator so it should have been a simple plug in. Probally a bad ground or a dying alternator. If your battery is fully charged and you are not driving it far you battery could easily last days.

bigmudr · 10-02-2005, 09:26 PM

i maintain my argument. disconnect the battery from the vehicle. now take a wrench and touch both posts. there is no draw but it still sparks everywhere. the more of a draw there is on the battery, the more of the 12 volts being consumed by something else, which means in theory that there would be less spark. its just making the connection and jumping the gap. i will apologize for the battery life without being recharged. i was wrong with that as they are rated for a certain amount of hours to run by itself. that rating is without any accessories on though. thanks for correcting me there.

chevyguy · 10-02-2005, 10:12 PM

Just bumpin ideas around trying to help this guy. But i still maintain with no draw there is no spark. The wrench in question acts as a path and completes the circuit. If there is nothing on then there is no circuit to complete until something is turned on. put a wire on one terminal and on the other and dont touch them. Same effect , No path, no spark

bigmudr · 10-02-2005, 10:52 PM

okay, i see your point of view. i was misunderstanding your argument. sorry to disagree with you . i was arguing a different point.

chevyguy · 10-02-2005, 11:04 PM

No harm. It is sometimes hard to get your point across the keyboard. my mind doesnt always accompany my typing .

quadracer · 10-05-2005, 08:43 PM

i appreciate all of your help, you have cleared a few things up for me.

i am pretty sure now that it is the alternator because when i had time today, i recharged the battery, and started it, and the volt meter was almost to the red by the "8" on the volt (recharge system) meter. I turned on the lights, and the volt meter moved a little bit closer to the 8.

i will take it to advanced auto or somewhere to get the alternator tested as soon as possible and reply back..

thanks for your help..

Quadracer

09-30-2005, 08:16 PM	#1
quadracer Junior Member Join Date: Sep 2005 Posts: 2	wireing shorttage or alternator problem? I have a 1986 GMC stepside. The guy that had it before me put a 350 5.7 liter in it.(origianally 5.0 liter), and the wiring on it isnt too hot either. my question is, could it be possible, the idiot that did this before me wired the alternator wrong? for instance, bought a brand new battery(die hard), started and ran fine for about 4 days. Then i started to notice when i started it, it sounded like the battery was getting close to dead. Another 2 days, dead, won't start. So i recharged the battery, ran the short test, which is if there you disconnect the - termenal on the battery, and hit it against the - stub on the battery, if it is a small spark, then there is no short. Small spark, so there is no short. so my theory is, is it possible that someone hooked the alternator up wrong, and instead of recharging the battery when the motor is running, the alternator isn't recharging the battery, instead it is just running the truck. i mean, starting the truck every now and then will slowly drain the battery if it isnt getting recharged by the alternator???? how can i test this???????????? thank you for helping me. Quadracer

10-01-2005, 12:12 AM	#3
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	Flag on the field. If there is nothing drawing power then there shouldnt ba a spark when you connect the battery. To check alternator output simply start it and do a voltage check at the battery should read about 13 volts. As far a wiring it wrong the 305 and the 350 use the same alternator so it should have been a simple plug in. Probally a bad ground or a dying alternator. If your battery is fully charged and you are not driving it far you battery could easily last days. __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

10-02-2005, 10:12 PM	#5
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	Just bumpin ideas around trying to help this guy. But i still maintain with no draw there is no spark. The wrench in question acts as a path and completes the circuit. If there is nothing on then there is no circuit to complete until something is turned on. put a wire on one terminal and on the other and dont touch them. Same effect , No path, no spark __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

10-02-2005, 11:04 PM	#7
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	No harm. It is sometimes hard to get your point across the keyboard. my mind doesnt always accompany my typing . __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

09-30-2005, 08:52 PM	#2
bigmudr Full Member Join Date: Jan 2005 Location: columbus, in Posts: 18	first, i doubt the alternator is wired wrong. a battery running by itself without the alternator wont even last 1 day, let alone 4. most will only run for a couple of hours tops. on an alternator, there is a power in and a power out. some have external grounds but most are case grounded. its really hard to screw one up. it is possible that the alternator is going bad, though, and just not recharging everything like it should. this kinda sounds like it may be the problem as the battery life shortened from 4 days to under 2. i would have your alternator checked out by a pro to be sure. too many people pretend to know what they're talking about. while some do, most don't. (just to be clear, i am a gm technician, but i will admit if i don't know something. nobody knows everything) as for your battery test, unless the battery is completely dead, there will always be a spark. that spark is just voltage jumping the air gap when you get close enough to the battery and again as you start to pull away from contact. sorry for the long answer but i hope that helps you out.

10-02-2005, 09:26 PM	#4
bigmudr Full Member Join Date: Jan 2005 Location: columbus, in Posts: 18	i maintain my argument. disconnect the battery from the vehicle. now take a wrench and touch both posts. there is no draw but it still sparks everywhere. the more of a draw there is on the battery, the more of the 12 volts being consumed by something else, which means in theory that there would be less spark. its just making the connection and jumping the gap. i will apologize for the battery life without being recharged. i was wrong with that as they are rated for a certain amount of hours to run by itself. that rating is without any accessories on though. thanks for correcting me there.

10-02-2005, 10:52 PM	#6
bigmudr Full Member Join Date: Jan 2005 Location: columbus, in Posts: 18	okay, i see your point of view. i was misunderstanding your argument. sorry to disagree with you . i was arguing a different point.

10-05-2005, 08:43 PM	#8
quadracer Junior Member Join Date: Sep 2005 Posts: 2	i appreciate all of your help, you have cleared a few things up for me. i am pretty sure now that it is the alternator because when i had time today, i recharged the battery, and started it, and the volt meter was almost to the red by the "8" on the volt (recharge system) meter. I turned on the lights, and the volt meter moved a little bit closer to the 8. i will take it to advanced auto or somewhere to get the alternator tested as soon as possible and reply back.. thanks for your help.. Quadracer