Electrical System Tech

[nick c]

I started having some weird eletrical gremlins up at the NWW G2G.

had my altenator tested, NAPA said it was all good. Its a standard GM 1-wire altenator.

So I checked the voltage on my battery (its an Orbital), it was bouncing around 10.6-10.9 volts. Granted its just a cheap Harbor Frieght meter.

Couldn't check my amps because the meter reads a max of 10 amps.

I checked the battery in my DD and it read high 12 to low 13s in the volts. So is my battery toast? Its only about a week old.

:eeek:

 

[Not Jobless]

The battery should be at 13.7V roughly while charging, around 12V or so without the alternator/motor running.

You either have a short and/or an accessory drawing all the power down or the alternator is toast...

 

[blackcj71]

What kinda problems are you having? When you were checking the volts on your battery was it running of off? need alittle more information:awesomework:

 

[nick c]

The truck was off, and so was my battery cut-off switch so there was no draw on the battery at the time.

As for what problems I was experiencing. I can turn my eletric accesories on (fuel pump, cooling fan, Mojave Heater, lights) but when I try to start the truck I hear the solenoid click and the starter trys to turn the motor over but can't.

to me it seems like the alternator isn't working. If I were to start the truck, is there any easy way to check the alternator? Say like putting my volt meter on the out-put wire of the altenator and check the volts?

 

[blackcj71]

You can check the volts at the battery while the truck is running. Check it twice, once with all loads OFF see what your voltage is, and again with loads ON, heater, lights, radio etc. Should be around 14v with no load. You could have a **** battery too.

 

[ZedMikey]

As for what problems I was experiencing. I can turn my eletric accesories on (fuel pump, cooling fan, Mojave Heater, lights) but when I try to start the truck I hear the solenoid click and the starter trys to turn the motor over but can't.

That's exactly what you should get when your battery is reading so low. It doesn't have enough juice to turn the starter.

Jump it and check the voltages like blackcj7 said. Probably a bad battery or alternator, but it could be a short somewhere else in the system.

 

[nick c]

Well I got the altenator back in the truck today.

Pulled some numbers with my cheap-o voltmeter.

With the truck running and my electric fuel pump on I read:
13.85 volts at the Altenator
12.78 volts at the Battery

With the truck running and all my accesories going (fuel pump, electric fan, head lights, mojave heater)
12.03 at the Altenator
11.9 at the Battery.

Doesn't this seem ass backwards? Shouldn't the altenator be cranking out more with all the accesories running?

But after letting the truck run for 5 minutes, the altenator pumped out enough juice to the point I didn't need to jump start the truck any more.

 

[blackcj71]

Well I got the altenator back in the truck today.

Pulled some numbers with my cheap-o voltmeter.

With the truck running and my electric fuel pump on I read:
13.85 volts at the Altenator
12.78 volts at the Battery

With the truck running and all my accesories going (fuel pump, electric fan, head lights, mojave heater)
12.03 at the Altenator
11.9 at the Battery.

Doesn't this seem ass backwards? Shouldn't the altenator be cranking out more with all the accesories running?

But after letting the truck run for 5 minutes, the altenator pumped out enough juice to the point I didn't need to jump start the truck any more.

No, you'll always get less voltage output readings when you've got all your accesories on. Although your numbers seeem pretty low...

 

[nick c]

interesting. Good to know.

So numbers are low. What do I do?

Where does the power lead from the altenator on a GM 1 wire altenator usually tie back into the system? Should it go directly back to the battery?

Would a high out put altenator like a Powermaster help my issue?

 

[bobbed_84_toy]

interesting. Good to know.

So numbers are low. What do I do?

Where does the power lead from the altenator on a GM 1 wire altenator usually tie back into the system? Should it go directly back to the battery?

Would a high out put altenator like a Powermaster help my issue?

Check the simple stuff first. Check to make sure all the connections at the battery, cut off switch, grounds, etc, are all tight and corrosion free. Just a little corrosion can cause ya all sorts of trouble. I'd run the wire from the alternator to the power wire going to the starter to feed back to the battery. An H/O alternator wouldn't hurt, especially if ya plan on gettin a winch sooner or later :awesomework:

 

[Trevor]

Battery is junk. Take it back to Napa, have em put a load test on it.

 

[nick c]

Check the simple stuff first. Check to make sure all the connections at the battery, cut off switch, grounds, etc, are all tight and corrosion free. Just a little corrosion can cause ya all sorts of trouble. I'd run the wire from the alternator to the power wire going to the starter to feed back to the battery. An H/O alternator wouldn't hurt, especially if ya plan on gettin a winch sooner or later :awesomework:

Checked all that. everything is good. The altenator currently ties back into the positive feed for my accesories (lights, wipers, etc.). Ill try moving it over to the power feed for the starter, as thats where I thought it should be going.

Battery is junk. Take it back to Napa, have em put a load test on it.

Well thats what I thought, but then it started the truck yesterday so I was confused. Its a brand new battery so thats good, atleast I wont have to pay for it.