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post #1 of (permalink) Old 04-11-2000, 02:41 AM
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Electrical woes

I have a 82 Bronco with a 302 and after we installed the motor, we went to charge the battery and inadvertantly put 24 volts to the system.
Ever since this episode I have a problem with my lights and interior electrical components. The lights and other electrical stuff losses power if I stand on the throttle but it is find if the truck is sitting at idle. I can't find were the problem is but I suspect it to be a feed to the fuse box. The motor runs fine and doesn't seem to cut out or anything when this happens. anybody with thought's please give me some idea's

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post #2 of (permalink) Old 04-11-2000, 08:34 PM
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Re: Electrical woes

I would start with checking for burned wires. Check for melted insulation. If it only happens when the peddle is on the floor, It may be shorting a wire. From there, I would go to the charging system since it is directly related to engine speed. Start with the voltage regulator. They go for 12 bucks and are easy to replace, since they are mounted to the firewall with two screws and have one plug. From there, I would go to the alternator. There may be a problem with the rotor or stator and at high RPM's cause problems, but at idle it may not spin fast enough to do anything. Lastly, check sensors on the engine. One could be shorted and that circuit is not activated until the engine is at a certain RPM, under a certain amount of load, or throttle plate is at a certain position. Example: The Throttle Position Sensor is bad and is not activated until you are at Wide Open Throttle.

This is how I start troubleshooting the problem. Good luck, Eric

If it ain't broke, I can probably still fix it.
post #3 of (permalink) Old 04-11-2000, 09:22 PM
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Re: Electrical woes

The first thing I would check is the voltage regulator. I had almost the same problem with my 83 F-150. I would be driving along and the faster the RPMs and the longer I drove the less electrical power I had. If i stopped for a while and then started the truck again all would be well. It got to the point that nothing worked or barely worked, heater, lights, wipers, ect. It turned out that the altenator was feeding the battery a constant 18-19 volts and it caused the lead plates in the batery to swell and short out. My referance voltage was 12.6 but the longer it ran and the faster it spun the lower the voltage dropped, eventually into the 5-6 volt range while cruising. You can also tell if its overcharging the system if the battery looks swollen or the water is bubbling out of the cells. I replaced the regulator and problem was cured. Keep us posted goodluck.

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post #4 of (permalink) Old 04-12-2000, 01:58 PM
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Re: Electrical woes

A very common cause of this condition is forgetting to put the engine to chasis ground strap back on after installing the engine. I know because I did it! Everything seems OK until you wind up the alternator to a high enough rpm that it can really put out the current/voltage. The regulator mounted on the chasis is not seeing the alt. output very well and keeps asking for more. The amp meter in your truck pegs the stop at max until you lower the rpm. It will burn up your battery and it can damage if not destroy your wiring harness.

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post #5 of (permalink) Old 04-12-2000, 05:50 PM
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Re: Electrical woes

Although all the aforementioned conditions are possible I lean toward mg's explanation. To me it sounds like you've got some connection that is compromised when the engine is loaded.

Try this:
Chock wheels.....apply parking brake.
Open hood..........start motor
See if you can simulate condition by appling the throttle while foot is on the brake.
Have a competent person either man the wheel/throttle/brake pedal or visually inspect the engine compartment of changes in the harness attachment to the engine while you simulate the condition.
Assuming that you can simulate the condition....and assuming that you have someone you can trust behind the wheel......carefully wiggle the harness/ground attachments to the engine.
Hopefully you'll be able to wiggle the right wire and get the system to react by touch......narrow it down.....and fix it. Heck once you've figured out that it is some connection under the hood....you don't have to run the motor to locate it.

My money's on a connection from the altenator to the starter/battery conection that flexes somehow when the motor rocks.


Figures don't lie ....... but liars sure do figure.
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post #6 of (permalink) Old 04-20-2000, 11:40 PM
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Re: Electrical woes

Thanks all for the help. I am still trying to find it but when I do I will let you all know.

[img]/wwwthreads_images/icons/wink.gif[/img]If it's stuck, force it! If it break's,it needed replacing anyway!!!
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