At my wit's end, please help
 

Bear with me guys, I gotta vent. I am so frustrated right now.... this truck has been testing my patience lately, one problem after another. Possibly all related, maybe just one problem that I can't seem to solve.

Several weeks ago the new alternator over-charged and burned up some wiring from the alternator to the voltage regulator. That fix involved a second new alternator and three new regulators before going back to the original regulator (and adjusting it). The truck has been fine since then, until now.

Several months ago, the plan was to resuscitate my long-dead factory A/C. All new parts, and converted to R134. The third new compressor seemed good, and the shop advised me to install pusher fans in front of the condenser, so I did. They run off a relay triggered by the hot lead for the compressor. Everything seemed okay until a few days ago, I had been running the A/C for at least a half hour. All of a sudden everything died.... I blew a fusible link. Cut out the bad section and had just enough wire left to reach the distribution block on the inner fender. It started & ran. I assumed the problem was A/C related so I drove home without A/C (more than an hour due to construction). Truck worked fine.

My mechanic suggested running the compressor wire through a relay, so I did that. Everything seemed to be working normally. Today I made a short drive across town and something didn't sound right as rpm went up. Then I noticed the ammeter was showing an excessive charge, same thing that happened before when the wiring burned up. Got it home and felt the new fusible link, it was hot but not hot enough to burn it up. I had not been using the A/C.

I am at a loss. Either the alternator / voltage regulator is totally hosed, or something in the wiring is creating an excessive current draw. I'm starting to think it has nothing to do with the A/C. Not sure how to track down the problem, maybe start pulling fuses one at a time and watch for the charging rate to change drastically.

Sorry for the long rambling post. I am just so bummed out, I have owned this truck 41 years and never experienced anything like this.

Re: At my wit's end, please help
 

Take a volt meter and check the out put of the alternator. Then check the voltage regulator. Those external voltage regulators are junk. If it was mine I'd go get a newer one and wire it up.:chevy:

Re: At my wit's end, please help
 

Thanks for the help, Andy. There have been so many problems, I have lost track.... but I do recall seeing alternator output voltage going off the charts (over 18v and climbing with rpm). Question is, what would cause that? I can check it again to see if that's still happening. Not sure what to check on the regulator.

We went through 3 new regulators, none of them worked. When you say you'd get a newer one, do you mean convert to internally regulated? I asked my mechanic if that would fix the problem and he said "maybe".

Re: At my wit's end, please help
 

My 2 cents: The stock alternator does not run newfangled accessories such as electric fans, not enough power. An alternator does not push power, items draw power from the alternator. If you draw too much power, the alternator and regulator can't handle it. The stock alternator can handle a stock A/C blower motor, A/C clutch, the distributor/coil, stock headlights, tail lights and an AM radio with single speaker. If you start adding other stuff to draw power, you need a higher power alternator and some additional wiring and relays to run the new stuff.

Re: At my wit's end, please help
 

Agreed on all points. For the record, virtually everything on my truck is stock, with the exception of the pusher fans, which iirc draw 17 amps. The original 61 amp alternator had started getting noisy, so I replaced it with a new 80 amp at the same time I added the pusher fans. They are on a relay, as are the headlamps and as of two days ago, the A/C compressor. I have an aftermarket low-wattage radio that isn't turned on, and a GM HEI that's been there since the 1980s. So I think that -- in theory, at least -- we've covered most of the bases as to electrics.

Re: At my wit's end, please help
 

Put a 100amp one wire on and forget about it.
You are seeing high voltage, but who knows what amps.
I have never been a fan of the external regulator.
With the extra load you have on the stock system, it will have its work cut out keeping up.

Re: At my wit's end, please help
 

If you insist on keeping the outdated charging system I would suggest you check the continuity on the blue wire that goes to the alternator. It is the sensing wire that tells the regulator how much voltage is in the circuit and lets the regulator adjust the amount of charging time the alternator is on or off. If the continuity on the blue wire is lost the alternator will default to full output and overcharge.The regulator can also cause this condition as well as the red voltage wire from the main junction to the regulator.

The regulator is mounted in rubber plugs and must be grounded by a separate wire to the radiator support and also to the alternator itself. Sticky points inside the regulator can also cause the overcharge.

Converting to an internally regulated alternator will eliminate this problem as long as it provides enough output to meet the demands on your system.

Here's a thread on the conversion.

http://67-72chevytrucks.com/vboard/s...d.php?t=417872

Re: At my wit's end, please help
 

18 volts generally indicates a ground problem in light of the fact that you have replaced the VOLTAGE regulator.
Measure grounds with a volt meter under operating conditions. With one volt meter test lead connected to battery -(neg) post, make all ground tests and voltage tests from that reference point.
Voltage measurements to the body of the regulator should be a couple tenths of a volt. ~ 0.2 - 0.4 Volts. Voltage measurements to the Alternator body/ engine and to the truck chassis should be the same.
Measure the voltage at the Alt output and also the Batt + plus terminal. The voltage difference between these two ~ 12 volt measurements should be only a few tenths. A higher than normal voltage drop between the Alt and the Battery, will show up as a higher reading on the dash Ammeter (Battery Gauge). You can make a direct reading from the Alt to the Batt + terminal if you choose to.

An ohm meter test for bad grounds has no value to you, because the test is being made with the meter's internal AA battery which has insufficient current for a proper test.

My '67 has the original style 37 Amp, 10 Dn, with external regulator. AC, HEI, elec pusher fan, small Sony with Blue Tooth and elec trailer brakes. It could probably use an Alternator with higher output at idle to provide brighter idle headlights, but all accessories function properly at all times and the battery is always fully charged.

The external regulated Alternator is not the source of your problems.

The old Generator voltage regulators included a Current Relay with the Voltage Regulator Relay. Alternator Regulators do not include a Current Relay. As long as the Alt regulator maintains the proper voltage, the battery will self regulate the proper charge current.

When my '67 dash Ammeter starts showing a higher than normal charge, after normal start-up, I start looking for the battery warrantee papers. From this point, I know I have a couple of weeks left on the battery.

Next electrical addition will be completion of solenoid for dual saddle tanks. Wiring is in place, but I have yet to look seriously for tank pickups and gauge sensors. This solenoid will only draw current for a spit second when energized.

Re: At my wit's end, please help
 

I followed VetteVet's advise and converted to an internally regulated alternator 3 or 4 years ago. I run two 1600 cfm puller fans, high powered amp, under hood LED's, upgraded headlight harness with Halogen head lights, and factory air. The conversion is very easy.

Re: At my wit's end, please help
 

Mines converted to internally regulated as well. One of the best things I’ve done for the truck. Don’t get too frustrated it’s probably something simple right under your nose!

Re: At my wit's end, please help
 

Thanks for the help & encouragement, guys, it means a lot. It's time to read up on converting to internally regulated, sounds like that's the best route to go. I had left it stock configuration because it had been working just fine for 47 years and I saw no good reason to change.

I'll probably learn this while reading 'how-to' threads, but is an internally regulated alternator necessarily a one-wire alternator? Because it sounds like that, too, is the preferred way to go.

Also hoping I can convert my new 80A, or do I need to toss it and buy another new one? So many questions, better get to reading.

First, though, I want to do some testing per RichardJ's post above.

Edit: I started by checking the blue wire & the red wire that VetteVet mentioned. They tested good, and the regulator is grounded.

Re: At my wit's end, please help
 

I had problems with my stock charging system. External voltage regulator would hang up and not allow charge. A tap with a screw driver handle would get it charging again. I swapped in a solid state external regulator from Autozone. I think it spec’d for a late ‘60s chevelle. That solved to problem and was a cheap easy fix. (Could be an easy test for you.)

But, I still had a poorly performing alternator. The original 10SI doesn’t perform well at idle. Although it charged well while cruising, at a stop light with the headlights on and heater fan going voltage would drop off to 11.5v and keep going down. So, I swapped in a 12SI per this diagram as outlined in the thread VetteVet referenced:
http://67-72chevytrucks.com/vboard/a...7&d=1360950747

Also look at this website, lots of good info:
http://www.madelectrical.com

I’m really glad I made the switch. The12SI performs much better. Voltage never drops below 13.5v and normally sits right at 14.2V. Also, using that wiring schematic I was able to maintain the stock ammeter.

Re: At my wit's end, please help
 

Don't do the one wire. It's not a good system other than it works. here is what you need and it a direct bolt in for the stock bracket on the drivers side.

Here is some more info I found googled it.
12SI Series Alternator for Delco
94 Amp, 12 Volt, Self Exciting
Pulley Type: 1V
Mtg. Ear Clocking: 12:00
Mtg. Ear Hole Size: M8 x 1.25
OE# 1101240,1101245,1105648
PIC# 240-300,240-301,240-308
Lester: 7294
Vehicle Application:
This is what you ask for at the parts store.
Buick 1984-1987 V6 3.8L

Stocker
The wiring is simple enough.

If you do this upgrade take the time and strip the wiring harness from the voltage regulator back to the red wire going to the alternator.

Take the small red wire from the external voltage regulator and install it on terminal #2 on the new alternator.

Take the small brown wire and install it on terminal #1.
Put the big red wire back on the new alternator and your done. The alternator has the same exact setup as from the factory. It will know when to turn up the juice and when to turn it down depending on the system load.
More about this on the Mad Electric website here.
If your into getting the most out of your vehicle then you got to read this stuff. :chevy:
http://www.madelectrical.com/electricaltech/remote ...

Re: At my wit's end, please help
 

I took some readings per RichardJ, might as well post up what I saw before continuing.
Voltage to the body of the regulator (and to engine) fluctuated between 0.0 - 0.1V.
Alt. output and pos. batt term both read ~17.5V at fast idle, 16.9V at slow idle.
Reading directly from Alt output to pos batt term was 0.10V.

Unfortunately I still don't know just what to make of this information.

Andy, thanks for that last post. Is Lester the name of a manufacturer, or a rebuilder? And is 7294 the number for that particular alternator? I'm trying to match the Buick info to the correct part on Oreilly's website. So far no luck, probably just need to figure out the right model. 1987 Buick Century is not the right model.... :)

Edit: Still searching for the correct one. I found "Self Exciting" seems to indicate a one-wire hookup, which you said is not a good system. :confused:

Been searching the web.... I just might have found the right part, maybe. https://store.alternatorparts.com/pa...lternator.aspx

Feel like I'm spinning my wheels, gotta step away from this for a while.

Re: At my wit's end, please help
 

From Madelectrical website:

Model 12SI, output 94 amp, 9:00 clock position, ACDelco part number 321-269

This is what I used. Got it from Rock Auto for about $90 if I recall. 12:00 is NLA but you can rotate it.

Also from MAD:
12SI, 94 amp, at 3:00 (AC-DELCO # 321-266, Lester #7294-3)

Tell the auto parts counter person that “The alternator is for a 1984 High performance Chevy Camaro, with 5.0L (305G) engine, 94amp alternator

12SI, 94 amp, at 9:00 (AC-DELCO # 321-269, Lester #7294-9)

Tell the auto parts counter person that “The alternator is for a 1985 Buick Riviera, 5.0L (307Y engine), with Heavy Duty options and Air Conditioning.”

12SI, 94 amp, at 12:00 (AC-DELCO #none found, Lester #7294-12)

No AC DELCO part number or application was found for this output model at 12:00 position.

Re: At my wit's end, please help
 

Here it is.
12SI, 94 amp, at 9:00 (AC-DELCO # 321-269, Lester #7294-9)
Tell the auto parts counter person that “The alternator is for a 1985 Buick Riviera, 5.0L (307Y engine), with Heavy Duty options and Air Conditioning.”:chevy:

https://www.oreillyauto.com/shop/b/c...amp+alternator

Re: At my wit's end, please help
 

Thank you both, I'm starting to feel like we're making real progress!

But I still have this nagging question, what's causing my alternator to produce such high voltage? And is it accurate to say a new internally regulated unit will fix the problem?

Faced with buying still more new parts, I'd like to better understand what's going on. Forgive my lack of knowledge....

Re: At my wit's end, please help
 

In my experience, excessive voltage is due to a failed regulator. The alternator will put out all kinds of power, but the voltage regulator...regulates it. I'm seeing some differences of opinion, though. I have a '70 Truck with AC and radio, and other accessories. Nothing changes in any big way when I'm at a light with the AC on (except it gets hot, which I'm fixing with a new Cold Case radiator). Fact of the matter is that my system has less load due to using a bunch of LEDs in various places. As far as I can tell, it's the original alternator, that has yet to be rebuilt. It's pretty crusty.

Re: At my wit's end, please help
 

http://www.madelectrical.com/electrical-tech.shtml
some good reading here

Re: At my wit's end, please help
 

Here's another thread with good alternator and wiring upgrade discussion
http://67-72chevytrucks.com/vboard/s...d.php?t=763180

Re: At my wit's end, please help
 

X2 on that. I just had the exact same problem. Also fixed the connection in the blue wire by soldering a new connector on.

Done.

Not Ever Give In.

Now if I had the electric fans and such I would be doing a CS130, CS144 upgrade with the 3 Wire set with remote voltage sensing for better power distribution with better or upgraded wiring.

Re: At my wit's end, please help
 

The alternator makes the power and it is regulated by the voltage regulator.
If the contacts stick closed in the V regulator then the alternator has no governor to control it when running. It will max it's self out and this is why you have 17-18 + volts.

Just some food for though.
A 1 wire alternator will work but it want have the capability to control the charge like the 3 wire.
A 1 wire will charge at the same amount no matter what the load is on the battery are the rpm of the motor, where a 3 wire will only charge at a rate enough to keep the battery at a constant charge so it want ever under charge it are over charge it.:chevy:

Re: At my wit's end, please help
 

I would go with the one wire and also run a larger wire from the alternator to the starter. I would get the 110 amp or above. I had a regulator stick once and it overcharged until the gel ran out of my optima battery. At that time I was running two spal fans that pulled alot of amps. Tim

Re: At my wit's end, please help
 

I would like to verify some of the facts here. First off are you running an alternator and regulator set like pictured below?

Now the time line.
Several months back you added new fans and relays to operate them as well a a relay for the compressor clutch. Shortly after that your fusible link failed.

Then several weeks ago you installed a new alternator. And shortly afterwards you had several wires melt down. You said you changed the alternator as it was noisy. The new alternator was an 80 amp unit instead of the factory 62 amp unit shown above. At this time you problems getting the charging system to operate which you solved by swapping several regulators before going back to the old one and adjusting it. The new 80 amp alternator was damaged when the wires melted? It was replaced with another 80 amp alternator?

You have installed a voltmeter and disconnected your amp meter?

Firedemon's link to madelectrical will help explain the difference between 1 and 3 wire systems in a coherent manner. That will give you the knowledge to decide which way to go if you are going to change to a newer internal regulated system.

Re: At my wit's end, please help
 

An 80 amp alt. draws too much field current for a standard point type regulator. It will burn the points & make them stick. You need an internal regulated alt. or solid state regulator.

George