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Alternator running with the "red" wire disconnected?!


lansisco
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I have an 84 Pickup 22R with a Carbureted engine and a 4 speed manual trans. I just got home from a 1,500 mile trip through Michigan's Upper Peninsula and was happy to be home safe when I was checking under the hood and noticed something very strange. I was checking the alternator belt tension when I noticed that the wire that goes to the positive post in the back of the alternator was not connected at all. It appears that the stud that the wire attaches to has broken off at the inner nut, and the wire head is just hanging there next to it. The voltage light has never come on, and the rig seems to run as normal. 

I had some unusual things happen with my motorhome while driving, but nothing that concerned me. For example, when I turn the headlights on, after about 5 seconds the ceiling fan beeps as it does when I initially start the engine and power begins flowing to it. When I turn the headlights off, 5 seconds later the same beep. I've noticed that while driving on bumpy roads the thing occasionally beeps as well and I assumed it was a bad circuit board or bad wiring on my part (I do a good job with wiring and I just can't imagine any of those connections weren't solid, and this beeping issue has gone on since day one of installing the new fan).

About a month ago, I was driving down a VERY rough road for about a half hour and parked at a gas station for fuel. When I went to start the motor, nothing. I looked under the hood and noticed that the engine battery had worked its way loose and wasn't connected. I pushed the cable down on the post and all was well. This tells me that I certainly had a working alternator...

But???

What if the wire head was touching the back of the alternator post occasionally and enough to keep the battery charged but yet not strong enough for full electrical capacity? What if the thing broke off just as I returned from a 1500 mile trip? (doubtful to me, as the roads were smooth for the last 350 miles, and why would it just break off?).

Would the wire harness that clips on the back of the alternator allow for sufficient backfeed/current to keep things charged and going fine for 9 days on the road? I would plug into shore power for days at a time and I wondered if the house battery somehow kept the ignition system going.

So weird, so what  do you think?

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It is possible, you have 2 batteries on line with the key on. I have seen that before a broken B+  wire. Day time travel you might get away with it. The red wire has to be connected to charge the battery no exceptions, the other small wires are charge regulators and dash light.

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I took a good look at things tonight and used a charging tester. No charge indicated, as expected. The coach battery was still fully charged, but the engine battery was down about 1/3 according to my tester. I can confirm that the stud for the positive wire was cracked right off at the inner nut. Seems really odd to me, but it happened. I'm planning on pulling it out amidst a hose and coolant replacement once I get all the parts in order. If the alternator can easily be repaired, I'll go that way and try it. 

If it doesn't work my intention is to go with a GM one wire alternator that is made possible by a kit from LCEngineering for a total cost of about 200 bucks. Strength with this is more amperage as well as much easier and less expensive part sourcing in a pinch. 

As a side note I tried touching the alternator wire to what is left of the positive stud while the charging tester was connected. I got nothing whatsoever. Is it possible something within the alternator was damaged by the wire disconnecting?

 

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The red wire needs to be connected for battery sense voltage. A GM one wire can work but you are going to loose some functions and the mounting can become an issue. The Denso alt's a pretty good units.

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I've disconnected my alternator, but I can't figure out how to get it out... Any pointers?

 

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If you have power steering it can be a major pain. No one gave me a clue as to how to get it out. I figured a way. Remove fan shroud then disconnect tranny cooler line on that side. You can get it out the bottom if you wiggle and turn it enough. Just barely though. New one goes in same way. Remember to plug your tranny cooler line while your working

Linda S

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I don't have power steering, nor an automatic trans. I'm happy to replace the coolant hoses in the mean time, and it seems like taking the lower one off is the best option. I'm not in a hurry as the new alternator arrives tomorrow. Thanks btw, Linda!

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Funny how things work... I loosened the upper alternator bracket and there was plenty of room to take out the alternator. It appears that the wire had made contact with the positive post while the engine was running, and arc welded itself to the post at least temporarily. In retrospect I think it had been there a long time, perhaps years. That would explain the weird voltage drops that caused our Maxx fans to beep when I would turn the headlights on or off. I just attributed it to an old battery isolator or some other electrical gremlin that wasn't serious.

So that settles the alternator issue.

Now on to the rest....

I spun the fan and heard a slight grinding sound and realized the fan blade had some wiggle to it. I thought that was odd, so I took the fan clutch off of the water pump and it turns out the water pump bearings were failing and had 2-3 mm of wiggle back and forth. I actually was thrilled to figure this out because I thought I heard something developing under the hood but I couldn't put my finger on the sound. It was like a belt squeal but much more of an echo than normal. It sounded like metal on metal a bit. Well, that was the source of the weird noise.

Onward to replace the hoses, belts, water pump, thermostat, and coolant with high quality parts. Since I've gotten it torn down this far I may end up buying the alternator brackets from LCEngineering that would allow me to put a GM one wire alternator under the hood for an improvement on amperage. I'm familiar with this type of alternator and have used it in other modified vehicles. That is one that every NAPA in North America has in stock constantly, (although I've never had to replace one).

I'm half tempted to pull the drivetrain and do the clutch at this time as well, but I am not sure how far down the rabbit hole I want to go during the warm months. Thanks for all your input everyone!

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While you got the front open to replace the water pump it’s a good idea to replace the crank oil seal. On the 20R &22R this is a common fail item. Easier to do it now than do it later. Seal only costs a couple of bucks.

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The oil pump is right behind it so while you are there replace the oil pump seal where it fits to the timing case.

 

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Posted (edited)

The engine has 100,500 miles on it as of today.

Are we getting to the point where I should just pull the motor and do a head gasket job as well as all new lower seals? I don't burn any oil over thousands of miles. It blows my mind actually. I am tempted to do a clutch job at the same time as this anyway. I also would like input on replacing my carb with a weber. My exhaust is toast so I planned on a header kit because they are the most cost effective way to replace the exhaust manifold.... Again, how far do I go at once? 

Edited by lansisco
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Look at the timing chain before you make a decision. Look at the teeth of the sprocket, at the chain guides. The factory guides are plastic, MOST replacements are metal. If the guides are plastic then think about replacement chain, sprockets, guides and a new tensioner. If the guides are metal

then most likely somebody has done the deed.

Most folks remove the head, so your head gasket question is moot. HOWEVER if it ain't leaking leave it alone is some folks view of life. I have changed the chain with the head on.

The front seal is sorta easy. I have changed the oil pan gasket with the engine in frame, it required some creativity.

If you do the clutch make sure you have a complete kit. Also a rear seal

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  • 4 weeks later...

I bought a GM One Wire Alternator Bracket from Summitracing.com for about $81 (TGI-120120-1-KIT) a Powermaster 100amp Alternator (PWM-7294)for $124, and a battery isolator kit off of amazon.com for $115, (KeyLine Chargers 12V 140 Amp Dual Battery Isolator Voltage Sensitive Relay (VSR) Pro Dual Battery Kit).

 

This allowed me to remove ALL of the Toyota charging mechanisms and just start from scratch. I was in the process of replacing the alternator, water pump, all of the hoses, belts, and I adjusted the valves at the same time, so getting to the alternator was easy since I'd removed the radiator to get to the water pump etc.. I was really nervous about messing with the stock alternator bracket because it was integrated into the motor mounts. This turned out to be really easy. I placed a jack with a block of wood on it below the oil pan and lifted the engine slightly, enough to take some weight off of the mounts. I undid the 4 bolts that hold the stock bracket in place and wiggled the stock bracket loose. I then wiggled the new bracket into place and was surprised that it only took some light taps with a wrench to line it up with the holes. The stock bolts are used in 3 out of the 4 holes, and there is a bolt that is included with the kit for the 4th as it needs to be shorter since the new bracket is thinner at that point. Surprisingly again, the bolts went in easily. The stock bolts looked brand new and I'm thinking to myself wow, they were installed 38 years ago. 

Once the lower bracket was in place, I put the GM alternator in and it lined up easily. My only issue was that I needed a belt that was 1 inch longer than the stock one. Easy fix and I was going to do the belts anyway. 

 

I completed the alternator install in under an hour, and finished up the rest of the work over the course of the weekend.

 

The battery isolator kit had about 20 feet of 7 gauge copper wire and was more than enough to run a wire from my alternator direct to the engine battery +, a wire from the engine battery + to the isolator, and a wire from the isolator to the coach battery +, with about 3 feet left over. There is a one foot, 4 gauge ground wire that I ran from the coach battery to the place the old voltage regulator was mounted under the hood. That spot was a nice thick bolt and made a great ground location. I used that ground for the wire from the battery isolator as well as the coach electrical system ground wire. Once I fired up the engine, I had 14.5v at both battery terminals. The headlights are very bright and the system is sound.

 

I made it a point to use Toyota hoses, gaskets, and a water pump from 22reperformance.com. I replaced all of them and they were not cheap. But I value my vacation days highly and I avoid problems associated with maintenance whenever I can.  

 

Would I do this again? YES! Do I care that I lost function of the voltage warning light on the dashboard? No, not in the slightest. I may install a voltage gauge at some point, but I am not worried about that alternator or the related parts. I recommend the powermaster alternators because they are new, not rebuilt and American made from scratch. 


As a side note, adjusting the valves was far easier than I was imagining and I found 3 valves that were way too tight. In adjusting them I have increased acceleration noticeably.

 

I had an old solid state battery isolator that I removed and replaced with the new kit. 

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Fix the dash lights...https://www.americanautowire.com/shop/11-volt-system-test-module

Can be done, but about the same $$ as a voltage meter

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That's really interesting. As I think about my situation, I've completely done away with the stock charging system and am bypassing it entirely. The dash light doesn't come on so that isn't a concern, and I've removed everything related to the old system to keep it simple. My connections are direct to battery and don't involve anything from the stock system. I will likely be adding some gauges to the interior for voltage and oil pressure and maybe a tach. 

Edited by lansisco
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