Roland’s random electrical aggravation 2023:

I have an annoying electrical issue with Roland my 85’ 22R pickup with about 186k miles. Recently replaced the engine, cracked exhaust manifold, intake and carburetor. It still needs some adjustments but has run good until this last summer. I have been using it as my daily driver (11 mile commute) all summer while fixing a few things on my Tacoma that cropped up/broken during my last fast AlCan trip.

I recently installed some driving lights for fall use, and also installed a switchable volt meter/ usb charger.


A couple weeks later I started experiencing a troubling random issue. While driving to and from work(and just about anywhere else) the charging light would come on while driving- so I would turn on the volt meter and check the volts, it would read 12.9-13.2(plus or minus) volts then start dropping to 12.7 or even less. Initially this might only last for a few minutes, then bingo charge lights go off, voltage comes up to 14.4 and normal voltage till the next event.

I checked battery connections, looked for loose wiring, tested the battery condition, and charging system. Everything looked good/normal. This normal reading would last for a week or less and occur again- totally random timing, I couldn’t tie it to bumps in the highway or anything else.

Eventually it happened in the driveway, so I tested the charging system using a Solar BA 9, got good reading for the battery, and poor readings for the charging system, while doing this the anomaly stopped and ops were back to normal as were voltages-14.4V. I retested the battery and charging system, and everything checked out good and normal. So I suspected there might be a loose or back ground, the 6AWG ground cable from the block to the body looked pretty dodgy so I built a new one and hooked it up and tried that. Same basic thing happened with random,though not immediate, slightly increased frequency. Obviously this reduced my driving to just commuting and shorter trips. Luckily by that time I had finished work on the Tacoma and was able to use it for longer trips. While still trying to figure out the issue, along with all the other stuff that needed to be done around the area.

Fast forward another week, and the next odd thing started to happen, again at totally random times. I would park my truck and if I wasn’t happy with my parking job I would reposition the truck - the truck decided to not even start- no charge light, not even an idiot light, not an ideal situation. So after work I got another mechanic buddy to have a look at it with me and it started just fine. We jawed about it, wiggled a few wires, really didn’t find anything and so I went home.

Needless to say this began to happen a bit more frequently with the same random occurrence schedule. Luckily the weather started a few weeks of random rain ( no garage of course )which was absolutely no help.

So I parked it for a bit to get caught up on other life stuff till it dried out some and went back at it from a different angle. I replaced the alternator, disconnected the ground cables and cleaned everything figuring that it might not be getting a good ground. This did help, consistent voltage readings lasted almost the entire day of doing errands.

then it happened yet again, this time over in town 18 miles away after I took the alternator core in, and went to the store. Then it was no lights at all, charge or otherwise, no clicking, I could hear a solenoid clicking somewhere under the dash behind the radio. But nothing. So I got it towed home the next day, parked it and said F$&k till next summer, and proceeded to jump into getting ready head outside for the winter.

So my plan is to go through each ground a clean the mating surfaces up, build new ground cables and start looking at upgrading/replacing the starter solenoid and going through the starter wiring and possibly the ignition switch. Chase down and print the pertinent wiring diagrams, and research the hell out the topic - not overly successful on either angle so far.

Not sure what else to look at. Any ideas out there?

 

I would check the fuse boxes and make sure everything is working and fastened properly (ground/power/signal wires). I would also test/swap the voltage regulator/rectifier in the alternator since you are getting voltage drops/spikes. Other then rats eating at your wires, the only other thing you can test that is associated with this would be your ecu. One other possibility for voltage to drop like that would be a big load on the charging system.

 

Battery ground cable. Check both + and - cable connections at the battery. Many times they look tight, but are not.

Grab each terminal with your hand and see if it moves when you use a twisting motion. If it does, that’s your problem.

 

Strange. First issue very well may be an intermittent alternator issue, second issue may be an intermittent starter issue. Being that they’re happening together, I’d bet that you have a bad ground somewhere-despite what you’ve already checked. The next time you have either issue connect a booster cable from the battery to the engine block, and another between the block and vehicle frame, check for a change.

 

Yes it is head scratcher, the combination is the puzzling aspect.
I will definitely go that route when I get back up north. Thanks for the great tip!