I have Southernboy6.2's(also known as Justin) 82 Blazer with a 6.2 sitting in my yard and want to either buy it from him or help him get it running. The choice is his, but anyway, here is the problem.
He suddenly started seeing problems when the voltage gauge would sometimes not give him a normal reading and the truck would act like it had dead batteries, but clear up on its own. Well all of a sudden, it acted like the batteries were dead and no start, even when being jump started. He replaced the alternator and one battery(lack of money replacing both at the same time) and truck ran fine for about a week and a half. Suddenly truck started doing the same thing so I brought it to my house on a trailer. Now same problem all over again, even after I put a battery charger on both and had them 100%. And to add to this fun mess, Justin decided to try a bigger alternator and was taking off the existing one and did not disconnect the batteries and melted a double red wire that changes to a single red wire and connects to a block terminal on the firewall right in front of the driver.
Now the question is what do you guys think the original problem was and how bad do you think he added to it. If needed, I can take pics and post em up. Thanks in advance for any help, I am asking the questions because he has little to no internet access.

 

Check out the contacts. Look for shorts. Its important to keep the battery contacts clean on 6.2/6.5.

 

He already changed out the terminals and even trimed the cables back for a clean connection. That is why I am so stumped with this. Is there a possibility that it is something in the starter? It seems to engage and try to fire fine, but just asking, I know electrical stuff can be a major pain in the

Mike

 

Could be a bad starter pulling too many amps.

 

Thanks, we will replace that next. He went 4 wheelin with the damn thing and I know the muddy water in the there probably didn't help anything.

 

I would be checking the fuseable links and all the wiring. There is a negative short somewhere causing the batteries to drain. Negative short is when a hot wire is grounding out somewhere and causes the batteries to become dead. I suggest you find that short. Repair the short then retrouble shoot the problem to assure the problem is fixed. Getting the electrical wet will cause the wires to corred which will cause high resistance in the wiring and eventually cause a short as well.

The good thing is there is not alot of electrical on the 6.2L or 6.5L engines so finding the short should not be a big job.

How ever you should not limit your search to the engine compartment. I suggest you check all the electrical circuits.

 

Some of the problem areas of 6.5s and probly 6.2s also is the battery posts since their side posts. One way to fix the problem is convert it to top post or extra washers for the side posts.

 

I aggree this is one of Chevy biggest down falls for alot of there vehicles. I suggest converting to top post. I also will say do not just get the top post adapters, get the new cables for top post batteries.