i decided to try again in the dark since it was a little cooler. I decided to separate D and E each with their own 20A fuse and connect directly to the junction block. Perhaps, in retrospect, that might have been dangerous to do so.

truck started right away. It stayed on continuously. No gas coming out the top (so must have been flooded earlier). Then I realized that I didn’t diagnose much except that 20A was not enough to run the D and E circuits together.

then I realized you said something in your last response to check and I re-read it. So I check the voltage across the battery and it read between 11.50 and 11.60. I thought that that was weird because earlier today it was reading 11.93. So I shut it off and check the voltage across the battery and it was 11.73.

something was pulling voltage instead of the battery being charged. Then it hit me. The alternator wasn’t charging and the engine was slowly draining to fire the cylinders. I began to loosen the negative battery cable and the truck instantly shut off. I opened the inline fuse holder for the alternator-junction box wire and the fuse was burned.

tentative diagnosis: alternator’s cr@p

but why?

will it be as simple as new alternator and new fusible link?

 

Depends. IF the same voltage was at the back of the alternator and you can get the battery to take a charge with a wall charger - get over 13V charging and charge to 12.6v then you are probably correct. If the alternator is hosed I may have been correct and you may have had a shorted diode which connects the battery to ground. You can of course remove the alternator and have it tested. Same with the battery.

George.

 

i will be taking the alternator to get it tested on Thursday and likely buying a replacement.

I don’t have a wall charger, so I will just hook up some jumper cables and charge with another vehicle.

 

the alternator was tested this morning and found to be good. It was charging 14.4-14.7 volts. I am at a loss to explain this.

 

You need to have the battery tested as well because it can have a shorted cell which can pull the alternator output down. Then make sure the battery is charge to 12.6 V hook everything back up and start the truck. Then measure the voltage at the positive battery post and then at those alternator output stud. If those voltages are different then you have a wiring problem. If those voltages are the same and 13 or 14 V then you’re good. If those voltages are the same but 11 and change then you have a field excitation problem and we have to solve that


George

 

charged the battery for awhile and brought it to store and it tested good (12.35V, so a little low, but no shorter cells).

tomorrow, I will reconnect both, charge battery a little more and restart.

 

This might be helpful:


George

 

alternator and battery reinstalled. Battery starting voltage 12.46V (the highest I could get it after hooking up to jumper cables).

started immediately. Immediately checking the battery voltage showed 13.1 V, then I checked the positive cable to the alternator and would get strange numbers bouncing around but which would always end up as “1L” or something weird (kinda like “wire not continuous” when you check the for continuity). If I changed the scale on the multimeter from 20 (where I normally check) to 200 or 1000, I would get a steady number (I don’t remember the numbers) for the alternator.

I shut the truck off and thought about it. Then restarted it and went to check everything again. This time the battery read 11.76V. I check the alternator and got “1L” again then immediately checked the 20A fuse on that line and it was blown again. I shut it down and now the battery is reading 12.10V

the fusible length (7 feet of it in case I have to do it multiple times)... was due to arrive today via fedex but shows delayed until tomorrow. That is why I tried again with my fuses.

I also did not want to keep checking since I noticed oil smoking near the exhaust..... it never ends with these money pits!

 

fusible link of the same size (1.0 SQ) arrived . I removed the two 20A fuses I had on D and E and I cut the same length out of fusible link and placed it inline just as B had been before.

truck started up immediately. Voltages measured with the negative on the chassis ground and the positive on the battery positive post (14.36 V steady) and the positive on the positive terminal of the alternator (14.87 V steady).

After running for a few minutes, I shut the truck off. I went to check the fusible link. It was warm to the touch, but not hot. The adjacent wires in line were cold to the touch.

thoughts?

 

How did you connect the fusible links?

George