Author Topic: Voltage spike...?  (Read 32415 times)

Offline 454Man

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Voltage spike...?
« on: August 06, 2013, 09:00:19 PM »
At my wits end on this. I believe there's a short between the supply write going to the fuse box and it's connection to or in the fuse box. Blade type fuses. If I have to many things on at once it shorts(losses it's connection to the battery. The volt meter on the dash goes all the way to the right. But I go to the battery under the hood and get just 12 volts. Does anyone have pics of the fuse box separate from the truck?

Offline 454Man

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Re: Voltage spike...?
« Reply #1 on: August 06, 2013, 09:28:29 PM »
Changed parts list: starter, alternator, battery 2 ignition switches, fuse links (now replaced with breaker style fuse,) wires in charging system currently about to change the wire going from the alternator to starter. I know this has to do with the amp draw on the fuse box after all the trial and error.any help and opinions appreciated.
« Last Edit: August 06, 2013, 09:38:39 PM by 454Man »

Offline zieg85

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Re: Voltage spike...?
« Reply #2 on: August 06, 2013, 10:54:38 PM »
How new are your battery cables?
Carl 
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1986 C10 under construction
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Online bd

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Re: Voltage spike...?
« Reply #3 on: August 06, 2013, 11:08:46 PM »
I assume you replaced the parts listed in your second post, chasing this complaint.   :o   Stop throwing parts at it! 

If I'm tracking with you, when you turn too many appliances ON the voltage available to those appliances drops off toward zero.  Are all of the electrical appliances in the truck affected, or is it limited to a particular area of the truck (e.g., dash and cab interior only, exterior lights, just certain accessories, etc)?

Do you have a test light?  Do you have a voltmeter?  Do you know how to make voltage drop tests and what they indicate?

Have you verified that the engine, cab and frame are properly grounded to the battery?

So we don't confuse each other, it sounds more like you're describing excessive resistance buildup in a circuit (a partial open or poor connection) than a short. 

As zieg recommended, check your battery cables and cable connections first.  Then move on to the questions listed.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline rich weyand

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Re: Voltage spike...?
« Reply #4 on: August 06, 2013, 11:42:00 PM »
Have you verified that the engine, cab and frame are properly grounded to the battery?

Start with that!  Search "engine ground strap" on this forum.
Rich

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Offline Irish_Alley

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Re: Voltage spike...?
« Reply #5 on: August 07, 2013, 12:51:15 AM »
have you taken the firewall connector off yet? check the connection there also
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Offline 454Man

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Re: Re: Voltage spike...?
« Reply #6 on: August 07, 2013, 07:47:18 AM »
have you taken the firewall connector off yet? check the connection there also
I Haven't taken the fuse box connector off yet. I didn't want to break it (trucks my daily) I will admit I've never taken one off. Prob could be right there...

I assume you replaced the parts listed in your second post, chasing this complaint.   :o   Stop throwing parts at it! 

If I'm tracking with you, when you turn too many appliances ON the voltage available to those appliances drops off toward zero.  Are all of the electrical appliances in the truck affected, or is it limited to a particular area of the truck (e.g., dash and cab interior only, exterior lights, just certain accessories, etc)?

Do you have a test light?  Do you have a voltmeter?  Do you know how to make voltage drop tests and what they indicate?

Have you verified that the engine, cab and frame are properly grounded to the battery?

So we don't confuse each other, it sounds more like you're describing excessive resistance buildup in a circuit (a partial open or poor connection) than a short. 

As zieg recommended, check your battery cables and cable connections first.  Then move on to the questions listed.
Thanks! The factoty voltmeter pegs out to like 18 volts because the connection to the battery is lost and it only sends charging amps to inside.(when this happens my windows go up crazy fast) if I select the up button. It will also make my headlights and break lights stupid bright, so bright it blows the left and right signal filament inside the tail light bulbs :-()
Because I have the breaker style fuse installed out resets and either does it again or goes back to normal.

On the ground idea. Guess I could add some more. Can never have enough. I have the small one from the Neg Batt cable to radiator support. Neg Batt cable to alternator, ground strap to firewall and that's it what else do I need? Again thanks :-)
« Last Edit: August 07, 2013, 08:10:18 AM by 454Man »

Online bd

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Re: Voltage spike...?
« Reply #7 on: August 07, 2013, 08:29:27 AM »
You're full-fielding the alternator.  Which alternator are you using?  What happens if you disconnect the alternator?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 454Man

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Re: Voltage spike...?
« Reply #8 on: August 07, 2013, 09:07:14 AM »
10si
Did not unplug the alternator. Won't that fry it?
Full- fielding?
« Last Edit: August 07, 2013, 09:10:16 AM by 454Man »

Offline rich weyand

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Re: Voltage spike...?
« Reply #9 on: August 07, 2013, 09:37:25 AM »
On the ground idea. Guess I could add some more. Can never have enough. I have the small one from the Neg Batt cable to radiator support. Neg Batt cable to alternator, ground strap to firewall and that's it what else do I need? Again thanks :-)

You're missing one.  There should also be a ground strap from the front of the driver's side head of the engine to the frame rail.
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift

Offline 454Man

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Re: Re: Voltage spike...?
« Reply #10 on: August 07, 2013, 09:46:59 AM »
On the ground idea. Guess I could add some more. Can never have enough. I have the small one from the Neg Batt cable to radiator support. Neg Batt cable to alternator, ground strap to firewall and that's it what else do I need? Again thanks :-)

You're missing one.  There should also be a ground strap from the front of the driver's side head of the engine to the frame rail.
thanks :-)

Online bd

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Re: Voltage spike...?
« Reply #11 on: August 07, 2013, 09:58:12 AM »
10si
Did not unplug the alternator. Won't that fry it?
Full- fielding?

Unless you're running more than one battery, the only way to increase voltage above 12.6 volts is if the alternator goes into an uncontrolled overcharge.  Full-fielding means the alternator rotor (the field) is receiving full or nearly full battery voltage, forcing the stator to output maximum electrical energy.  In other words, the regulator isn't doing its job either because of an internal problem or because it is being tricked by an external wiring issue.

Unplugging the two-wire connector from the regulator will not damage the alternator.  It should just turn it OFF.  If the alternator continues uncontrolled output with the regulator unplugged, there's a short inside the alternator.

Did the problem begin before or after you replaced the alternator?

Post a clear pic of the wiring harness connections to the alternator.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 454Man

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Re: Re: Voltage spike...?
« Reply #12 on: August 07, 2013, 10:55:33 AM »
On the ground idea. Guess I could add some more. Can never have enough. I have the small one from the Neg Batt cable to radiator support. Neg Batt cable to alternator, ground strap to firewall and that's it what else do I need? Again thanks :-)

You're missing one.  There should also be a ground strap from the front of the driver's side head of the engine to the frame rail.
thanks :-)
Same problem 2 new alternators. Connector at alternator is new.

Offline 454Man

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Re: Voltage spike...?
« Reply #13 on: August 07, 2013, 11:17:38 AM »
I'll post a pic after work just don't make Fun of my birds nest lol
« Last Edit: August 07, 2013, 12:49:39 PM by 454Man »

Online bd

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Re: Re: Voltage spike...?
« Reply #14 on: August 07, 2013, 12:51:44 PM »
Same problem 2 new alternators. Connector at alternator is new.
I'll post a pic after work just don't makeFinn of my birds nest lol

LOL - Never cared much for birds nest soup....  ::)

When you take the pics, our main interest is in where/how the wires are connected/routed.  In the meantime make sure all grounds are in place and connections are clean and tight.  Do you recall the circumstances when the problem began?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)