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Drained battery-alternator or other?

J

Jesse Jaymes

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Just had a cam and intake replaced in my '79 K25. The battery was drained after the first day I got it back. The "Shade Tree" mechanic claimed that the battery was no good. I thought it was the alternator, but whatever.

So I bought a new Duralast battery. Installed it. Truck started and ran. Volt gauge in truck was about "10". It never increased or moved with added RPMs. So I thought it was again, most certainly the alternator.

New battery yielded more starts and good running-for two days. Then the volt gauge slowly faded from 10, to 9ish, then 8. Then came the dimmed headlights, and no stereo.

AutoZone tested the alternator in the vehicle. Claimed that it was only putting out about 11.2 volts. They told me it should be about 13 and that 12 was considered low. But it sounded like it was at least working somewhat.

Now I am finding out that it's highly probable that there is a short or a drain somewhere in the vehicle.

I am obviously pretty ignorant when it comes to wiring, etc.

I am broke as a joke and am looking to get a better understanding of how to fix my pickup.

Thoughts on where to start looking? The wiring for the alternator seems off to me, in that there is not hot wire going directly to the pos terminal. It runs from the batt to the starter solenoid and to the alternator. This seems like a stock routing.

Thoughts? I am away from home with the broken truck and about zero hand tools. I will scrounge enough to change the alternator, but I am not wanting to throw away $50.

Shouldn't the volt gauge fluctuate like the oil pressure gauge when under increased rpms?
 
Got a volt meter? If so, check the battery voltage, should be somewhere around 13 volts, then start the truck and see if it comes up to around 14 volts. It sounds like your alt is bad, but the voltage check is a quick check.
Or you can take the alt out and have it checked at Auto Zone. They have a machine that does a pretty good job.
 
That's my idea after work tonight since there a billion AutoZones around. Not sure if I can get the alt out with pair of pliers and a multi tool. Hate to buy a whole new set of wrenches or sockets, but it's bothering me, and I am kinda need it to get back home.

Still don't know where to begin if the alt is not the problem? Sure a volt meter is handy if I knew how to use one or what readings are good or bad
 
With the engine off you should get somewhere around 12.5 volts across the battery terminals, with the engine running you should get somewhere between 13.5-14.7 volts across the battery terminals. If you don't get at least 13.5 volts then the alternator or internal regulator is dead. If you can get a jumpt start (assuming it won't currently start) you should be able to make it home or to a parts store at least wth the dead alternator.
 
Well, I am F'd now. Used a .99 cent cresent wrench and was able to get the alternator off. Never saw brackets and crap like that. Was much bigger balls to get off than I thought.

Regardless, AutoZone teen tested the alternator TWICE! Passed both times.

Now I am about out of ideas or options. The bracket in which the alt is adjusted has the neg ground on top of the bracket. This was painted before being re-installed. I will sand off the paint where the ground attaches and pray, but have little faith there.

Can I get any help here in backing up to the original modification? I had the cam and intake swapped by Shade Tree. Worked fine before hand, and now battery not charging with a verified working alternator and new battery. What electrical connection or system was moved or altered to make the swap?

Ideas from here?
 
Forgot, fuel pump was swapped for electric pump. So once I am down to the last dreggs of juice I am dead in the water.

While taking it to get looked at by Shade Tree, I saw the volt gauge on the dash spike 2 times. Up all the way to 13ish for 3 seconds and back to 8 (bottom).
 
Guessing just dump the $44 on the reman alternator and go from there?

Relocating to Spokane, WA and winter is on the way. Guessing if it's not either the batt or alt, then I just invested in a piece of mind for cold weather starts?
 
If Vatozone is testing the alt, twice, at two different locations id think the alt is good.
I know, i know... but its hard to screw up the test on the machine they have. even harder to scre it up repeatedly. And the last time i checked the machine puts a load on it to make sure amperage is good, not just voltage.

Check your cables, esp your grounds. I think you might have a crappy ground, that would cause the issues you describe and still allow the alt to test good.
 
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