I did an engine swap from a V6 FI to a GMPP crate 350 carb. I removed the FI wiring and left the wiring for the coil, starter, alternator, etc. The problem I am having is the alternator wiring going from the B+ on the alternator to the battery (tried both with the junction box and w/o the junction box) is getting really hot. The connector from the alternator has two wires, one goes to a switched power and the other to the starter. I have an Optima yellow top battery. I have tried three different alternators and have had the same issue. I am going to try a different battery today and see if maybe that is the problem.
I used my volt-ohm meter to check for a short but do not see any problems. That is about as far as my troubleshooting for electrical goes. The car starts and runs great. It's just this one wire that is holding me up and it is the only one getting hot. If someone could give me some advice on how to troubleshoot this or even a good educated guess would help. I'm stumped right now. Any ideas will work. Please help. Thanks.

 

Hot wires usually mean a short to ground somewhere or way to much amperage coming threw. With a short to ground, something should have burnt up. Does the harness for the Alt have a fusible link in it? Is the Alt charging properly? Check the amp load going threw the wire. It may be to light of a wire for that much amperage. Go with something heavier from the Alt to the battery and then add a fusible link in the circuit in case all hell breaks loose.

Also, when you swapped, did you go to a coil that needs 6 volts? If so did you had in the resistor block for it and possibly send some voltage in the wrong direction?

 

Thanks for the quick response. There is no fusible link between the battery and alternator but there the one from the alternator to the starter(probably doesn't matter right now). The wire is 10 gauge. The alternator charges at around 14V. It's a 12V coil and I have a MSD 6AL ignition box hooked up to it. Not sure if that would make a difference.I will double check on the coil though just to make sure I have the right part. I will have to buy the right tool to test the amps my volt-ohm meter only handles 10A and I'm pretty sure its pulling more than that. Thanks for the help. If you or anyone else has ideas, please post. The longer the list of stuff to try the more likely I am to finding the actual problem. Thanks.

 

10 gauge seems to light of a wire. Step it up. Take a look under some other hoods of vehicles and compare the sizes. You'll see most have some pretty stout wiring going to the battery.

 

Should have a cable from altermator rated to carry the full amperage of the alternator, #4 or larger.

 

[X(] 10 gauge wire sounds like stock stuff to me(normal for gm since time began) and should handle your electrical needs as this should be stock and oe for your car. as for getting hot youll need to find a friend or a shop with a some sort of battery/ charging system test equipment, while it sounds as though your voltage is fine(this is what your alternater uses to determine its output) you need to determine your amperage output. too much amperage for too long and it will heat things up. ive seen batteries cause some very strange problems although optimas have been good batteries. second you need to CHECK YOUR GROUNDS!!! use your volt/ohm meter and check to be sure the alt is grounded to the engine block and the block is grounded to the battery and the chassis. where is the negative battery wire going to and what size is it?? how about the wire going from the block to the chassis?? grounds or VOLTAGE DROPS (bad connections) problems are also a major cause of wierd electrical problems. does your in car volt gauge or dash light work correctly?? i just checked my factory manuals and both the v6 and v8 schematics for 1995 anyway show only one small wire besides the big B+ coming from the alternator so depending on your year you may want to find and check some wiring diagrams( you are reusing the alt and wiring from the v6)?? let us know kurt

 

Ok it was the battery I was able to get a meter that could test high amperage. The Optima battery was pulling about 40A, a standard battery was about 15A. 10 gauge can only handle 30A. 8 gauge will hold 50A so I may go with that. I have to get ahold of Optima and see if this is the normal current this battery uses or if there is a defect in the battery. If its okay, I will probably have to upgrade the alternator, don't want to overwork the one I have. All the grounds are fine I should have mentioned that earlier. I figured that the 10 gauge was a little small for a charging system but I wanted to get down to the real problem before I started using a larger gauge wire. Thatwould belike using a 40A fuse when the 20A keeps blowing. It's just asking for trouble. Thanks for the help.

 

[X(] im not sure what you mean by pulling 40 amps, do you mean the alternator was charging the battery at a rate of 40 amps?? this may be normal if you have a load on the battery or it requires a charge or could be defective. remember before changing a bunch of stuff that the the factory has alternators that push 120 amps and i dont know ive seen much wiring in stock applications larger than 10 ga.(maybe some 8ga. for chassis with lots of electrics) are you sure there isnt a short somewhere?? a battery that requires a 40 amp charge would be quite strange as its usually other components in the system that cause draws that big. **if the battery is charged it shouldnt pull anything**. if your getting 40 amps your alt is probably fine. something aint right an i suspect a short or battery as the battery itself can have a short please get back to us kurt

 

Like I said it was the battery. The battery was pulling 40A from the alternator in order to charge itself orbecause there is a short in the battery. Itsa little highwhen there isnot much of a load on the battery and thereare no shorts elsewhere. I tried getting ahold of Optima but they do not have any technical people that can answer my question. So I'm just returning the battery and using my standard battery. Thanks.