This all started around 2 weeks ago when I went to replace the battery on my '79 SR5. The first one I got (different brand but correct amperage) made it loop/sputter at idle until it would completely die after a few minutes. After putting the old battery back in (24EXTJ), it fired up no problem and ran perfectly fine for a few days until I tried to start it about an hour after I got home from work, and got nothing. I figured it was a dead battery, so the next day I went out and got a new one, but was given a 24REXTJ (750 CCA 935 CA) instead of a 24EXTJ (700 CCA 875 CA). I didn't realize till I was going to connect it and saw the reversed terminals. I figured it should be fine as long as I connected to the correct terminals, since it was just higher amperage. The same thing that happened before happened, so I swapped out the battery for the correct one, but when I was installing it, I accidentally bridged the connection for a split second but that didn't seem to damage anything. It fired up and ran well for about 10 minutes, then the same sputtering started happening again.


At this point, I figured that the battery wasn't causing my problems, so I moved on to the voltage regulator/alternator. I went out to order a new voltage regulator (which should be here on Tuesday), and when I got back, I tried to start my truck to move it to a better position, but only got a single click, nothing other than that, and the dash lights. Worried that I may have drained the battery, I hooked it up to a trickle charger so that once I got the part, I wouldn't have to worry about a possible dead battery. After letting it charge for a few days, I tried to start it one last time and got the same singular click and dash lights. I did not notice that the voltage readout on the charger got up to 17 volts when I tried to start it that final time, which makes me think the voltage regulator is what I need.


I'm worried that something else is going on other than the voltage regulator, or that I fried some electronics from the multipull battery change attempts. Does this sound like a voltage regulator or a bad alternator to y'all? I've been waiting on parts for almost 2 weeks, so I've been second-guessing my diagnosis, so I would really appreciate some advice on this.


Other info:

All fuses looked good but I replaced the engine fuse just in case
Had the GM ignitor module fixed a few months ago
I have a video of the sputtering/looping at idle wasn't able to upload it

 

From my experience for the starter click but no-go, try giving it some tappy taps with a hammer of your choice - seems something gets hung up in the starter as this happens rarely but is annoying when it does.

since we both live in an "Extreme Climate" I just use whatever is the juiciest CCA/CA battery possible you can fit into the battery tray. More CA/CCAs = more cranking powa and reserve capacity (or so I've been told according to some buddies on a Toyota Van forum) since the batteries don't last more than a couple years at best, maybe longer if you maintain it on a maintenance-type.

As for the voltage/sputtering problem, if you could share the video that would be nice to see (visual/audio clues and cues help a lot more!) as I'm not sure on the "looping" aspect . Odd that the symptoms change with the battery changing but I can only offer so much insight as I play a mechanic online sooo I can only offer speculation.
Curious, why use a GM ignitor over the Toyota one? unless they're all NLA/chinese repros/second hand...

Put a meter on it and record your finding when you go to start/start it successfully it is where I would start. Then again I only have analog meters so you'd be better off set!

 

Thanks for your advice, I was able to get it fixed with the voltage regulator + cleaning up what little corrosion was still there. I'm fairly certain that both were playing a factor in it not running.

The reason the shop used a GM module is that the only ones I could find secondhand looked like they had been sitting at the bottom of the ocean for a decade and were $250+. This is what they suggested and it's been working great since then (4 months).

 

Good to hear

Haven't heard of using a GM module as a replacement, got a part number to share? Would be good to document