broskie, check your fuse by your left foot on the driver side for the alt.. if that fuse is out, your battery light wont come on and your good alt wont charge your battery. also you guys are crazy, my truck stays running if I take my battery out... I did it the other day to see if my alt was putting out good power... stock alt...

 

about 13 isnt gonna do. should be 13.8 to 14.8 volts depending on the load its under. maybe get a new parts guy. just sayin. hope you get things sorted out.

 

if your alt was good the truck will run without the battery. i've swapped dead batteries into running vehicles as a make shift charger lots of times. although it's not really recommended lol.

i'd go to a different parts place and have em check it, or just grab a new one. last one i bought for a 22r was like $30

also the easy way i was taught to look for a parasitic draw is put a test light between the ground of the battery and a ground on the truck. if something is on it will light up the light.

 

I have a alt ill sell you, Ive got a bosh, cost me 140 bucks, sell it to you 60 shipped.

also guys, the machine they use to test you alt is not accurate ! there are 2 types, one is accurate the other is not ! dont trust these, ask if theres is computerized or if its the old style.. the old does not work...

 

I have a knowledgeable guess of what it could be...

1. Alternator might not have good enough ground.
2. There is corrosion in your wiring or some connectors might be messed
up or not on correctly

I had #2 in my dad's pick up, this connector deal was all corroded and deteriorated its the one by the external voltage regulator sometimes they are purple or black...

 

Its the flux capacitor!



Truck should run if the alt is good, doesn't need a battery hooked up. Old school trick but, also not good for internal voltage regulators, which in your case it has one... Just get a new Alt and be done with it...

 

first check the alternator wiring/fuse.... use a multimeter and check continuity on both DON'T JUST LOOK AT IT

and i'm new to this forum so i don't know specifically about our trucks... but do you see any wiring out of the ordinary thats connected to the battery terminals or anywhere else?? if your battery and alternator is good yet the engine shuts down when disconnecting the battery something must be linked to the cables... perhaps the previous ran into some problem with the truck and ended up ghetto-rigging something direct to the battery so that the engine would run... something important like the fuel pump or ecu so that when the battery is disconnected they would be turned off. probably not your problem but i wouldnt keep my guard down....

a multimeter is your best friend right now. GOOD LUCK

 

My thoughts are, check fusing, check idle voltage from alternator at the battery post- not the terminals connecting to it. Check engine ground- this is what supplies the path of (-) Electrons between the Alternator and Chassis, and Chassis and Battery/other components. A battery does not keep the engine running, it is merely a reservoir for power. In my automotive experience and working at audio shops for years, your battery float should be 12.5-12.8, when engine cranked and idle, 13.5-13.9, before voltage regulation at 2k rpms you should see 14.5. The voltages are an average and will vary between vehicles.. just to give you an idea. And owning a multimeter is a must when working on electrical devices and makes life a lot easier and will save you money in the long run. Get a Fluke or Greenlee if you can afford it, if not a $25 Craftsman one from Sears is decent.

 

I was wondering what happened to this thread.

My next suggestion to you would be upgrading your electrical wires. The ones from the battery to the chassis, alt to battery, etc, etc. Bigger wires will increase flow and be better for the overall general electrical for the vehicle.

 

All good idea's. But I would unhook the battery. The. Trickle charge it over night. Load test it then Do a proper "in vehicle charging system test". That is a good basis to start on. If it all comes up good then do a draw test. If the battery fails replace the battery. If the alt fails just double check wiring. Making sure there are clean connections and no broken wires. Then if it all looks good Replace the alt.