Electrical S.O.S.

[kad]

Hey ya'll, I've been scouring the archives for a thread similar to my prob without success and I'm hopin for a little help... apologies for the length of this post.

After 400+k the electrical gremlins have finally found my trusty ol'goat, specifically erratic charging. About two months ago I had a battery go dead without warning. Now, it was an OLD battery. I bought new from NAPA and threw it in without any problems but soon noticed that my dash voltmeter (confirmed with dig handheld) wouldn't do more than approx 11. 5 with constant fluctuations (11. 2-11. 7. I measured at the alternator and the battery). Being over 400k on this stocker and electrically handicapped I went about cleaning the batt posts (very minor corrosion) and changing (in order) 1: volt regulator 2:belt tentioner/belt 3:alternator (old one benched fine but what the hell) without any change in the charging.

On initial startup I get 13. 7 but it slowly (over about 60 secs) drops down to that eleven range. As I turn on radio, lights etc... it drops further and if I turn on a blinker I can actually see a pulsing drop in the voltmeter which corresponds with the blinker actuating.

With the truck & equip off the batt sits at 11. 95. With truck off and all the bells and wistles on I get 11. 70. The truck is a 90. 5 and as far as I know I do not have one of those little PC'somethings hooked into the system.

Again, thanks in advance and sorry for the length on this but I'm at the end of my capabilities on it, S. O. S.

p. s. I drive daily and have never noticed hard starting or any sign of batt drain other than via instumentation (it is a big commercial NAPA batt).

 

[paccool]

If the truck is non intercooled it doesnt have the PCM. Also the early nonIC had seperate voltage regulators.



It may be a bad ground or something like that but I think I would take the battery back in and have them check it under load to see if it is dropping voltage too much. Could also be the regulator but you said it has been changed with no difference in the problem.

 

[RWWinslow]

I have been battling electrical gremlins for the past 12 to 18 months - it is something that you will not enjoy as the truck continues to age. Systematically go through and check all of your ground connections for corrosion. Check all of your ground wire lugs for corrosion in the crimped area - you will probably have to redo several of them - the corrosion will also work up under the insulation and follow the copper strands.



Check all of your weather tight electrical harness connections - the multi-wire plugs. I have found a number of these under the bed where the corrosion between ground wire and hot wires was sufficient to allow a voltage leak . . . . my fix was to solder and get rid of the bad connections - knowing that a full wire replacement is a couple of years away. Use a soldering iron and heat shrink.



My tail-light voltage was down to 9 VDC and after fixing a number of these issues it is back to 12. 7 - truck charging is at 12. 9 VDC.



Change the voltage regulator on the fire-wall if you have not already - check that electrical connection for corrosion, etc.



GOOD LUCK!

 

[Greenleaf]

Testing the regulator is in order as well as the battery. However, I have load tested many a battery that proved "good" and didn't function in real world conditions. They can fool you AND cause problems with the charging system.



The volt reg is tested by bypassing it. You will have full voltage output. Do not operate at this rate for long. A new regulator can be bad. Checking all grounds is sound advice. Do not mearly "look" at them. Clean them. All that you can find. Even the one under the dash for the gauges.



Battery cables can also become suspect. They will require replacement in time.



Because you see a normal charge voltage for a short period, I'd suspect the "new" regulator.



-S

 

[kad]

Thanks all for the good advice... will follow up when troubleshooting complete.

 

[kad]

After several afternoons of chasing electrons here's what I found: aside from the "southern engineered" trailer wiring and one bad tail light connection (loss of 2. 2v tot) the prob continued. I found that my "new" volt reg was bad... went and got another one which was also - bad - &%$# (whats the record on "new" bad v. regs anyway?). Finally I went wire grabbin' with the voltmeter hooked into the batt. I found that one of the poles coming off the alternator (this is a new alt) was broken off at the base. The nut and wire coupler held together giving the appearance of being intact but in reality they were just resting on the pole coming off the alt. - The second wire/nut were intact further holding the broken one "up". The "fix" involved dissecting the old alt for the connection and doing the swap. She cranked out 14. 7v consistantly for ~ 2hr test run. My only guess is I got a little too zealous in tightening that connection when I originally replaced the alt and snapped the pole (pretty flimsy to be sittin on a CTD).

Thanks for all who replied.