ok...now what do i do?

[tiggerstoy]

i have a 77 short/stepside with a 350 fuely to a 700r4behind it,it has the new style alternator.....this is fine, but i keep loosing power, i have a new bat, line's, terminal ends.....no blown fueses, volt meter works, but no power!
the truck will run on the bat- power till it runs out, alt is good(its been tested) ....im not sure ware to look next, but im running out of options, any help on this would be great, thanks in advance..........max.

[magnethead]

stick a multimeter on the battery itself while motor is running. It should register 14.4v to verify that the battery is being fed off the alternator (and again with engine off to verify, should be about 12.2 i think?) if it's being fed by the alt and still not holding, it might be a bad battery.

[tiggerstoy]

thanks.....i'll try that first, got so into looking for something big, that i forgot the simple things first.

[boatpuller]

take it to a auto shop that specializes in electrical repair.we have a couple in our area that iv'e used over the years.they hook it up and it tells what component is bad.it will save you from having to buy something you don't need.usually,they don't even charge for it.but i buy the part from them.i remember a few "dead" batteries that turned out to be a voltage regulator or alternator.but first thought was to buy a battery.live and learn.

[CLASSIC87']

I know this may sound crazy but check ur belt. Even though it maybe tight; it could be hard/old... and inturn slipn. Speaking from personal experience... I had replaced EVERYTHING- then took it to the shop and it ended up being the belt.

[tiggerstoy]

well...the belts are good, still waiting for the return of my volt tester, other than keeping the bat charged so that i can partake in the events in town for this weekend, ill get it to my work on monday(ware most of my tools are) and have a beter look.
thanks for the help all........max.

[Russell]

Max, if you don't get it licked by the time I finish my shift at work, I'll make a trip down and figure it out for you

However, here is a quick rundown on how I wired it up:

The big heavy wire coming off the post of the alternator should run up to the distribution block on your firewall just to the left of the brake booster. This wire should be connected to the battery at all times, and should read battery voltage within .2 - .3 volts or so.

The smaller pink / black wire is an ignition wire, it should have at least 12 volts any time the truck's ignition is in the on position. The other wire (brown if I recall correctly) runs to your instrument cluster, and grounds through the idiot light for the alternator (the light on the left if I recall correctly)

Make sure that the light is coming on when you turn the ignition to on, but that it turns off after you start the truck, if that light is burnt out, then the alt won't charge.

If everything checks out, I'd be considering your battery suspect, I've had batteries that were just a few years old crap out like that on me...

[magnethead]

Originally Posted by Russell

Max, if you don't get it licked by the time I finish my shift at work, I'll make a trip down and figure it out for you

However, here is a quick rundown on how I wired it up:

The big heavy wire coming off the post of the alternator should run up to the distribution block on your firewall just to the left of the brake booster. This wire should be connected to the battery at all times, and should read battery voltage within .2 - .3 volts or so.

The smaller pink / black wire is an ignition wire, it should have at least 12 volts any time the truck's ignition is in the on position. The other wire (brown if I recall correctly) runs to your instrument cluster, and grounds through the idiot light for the alternator (the light on the left if I recall correctly)

Make sure that the light is coming on when you turn the ignition to on, but that it turns off after you start the truck, if that light is burnt out, then the alt won't charge.

If everything checks out, I'd be considering your battery suspect, I've had batteries that were just a few years old crap out like that on me...

there's an idiot light for the alternator? My truck has no idiot lights to speak of...as in none. (seat belt is only light that EVER comes on)

[Russell]

This alternator is for an 88+ truck, 105 amp, which I retrofitted on to feed the power hungry TBI setup that I also retrofitted on.

They require you have an idiot light, or a resistor that is the same resistance as an idiot light to work properly.