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New Alternator Problems


PonyUp

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Need serious help with Alternator. I have a 1989 BR 2, 2.9, 4 WD, Auto Trans, Eddie Bauer. Alternator went out. Had a shop replace alternator and my RPMs, Battery gauge were off when I got it back. Took it to someone else and they tested it saying battery is good but voltage drops from 14 to 12? This shop said alternator was bad or the wrong one. Can't use AC as compressor clutch won't stay engaged and now my tranny fluid is burnt and having shifting issues. Went back to people who replaced it and they said nothing wrong with alternator. They did change the alternator but same thing is going on with voltage. I will take it to a tranny shop Monday but I am thinking that replaced alternator is wrong amps for my model and is causing all of issues.

Aside from tranny issues, does anyone know how I find out what AMP Alternator is supposed to go on my car? I don't have any after market add on and the gauge needle never fluctuated before. My RPMS on gauge were always the same at idle and now they are lower. No one messed with any idle adjustment. I need to find out what AMP this car needs and don't want to take it to a dealership. Thanks for any help.
 


RonD

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1989 B2 Eddie Bauer would have 80amp alternator, largest for that year, Ranger or B2

But doesn't read like your issue

You need a Volt meter to test, $10-$15 at wallmart or ???
Set to DC Volts

Key off
Test battery voltage, should be 12.3-12.8volts, REMEMBER IT or write it down
Under 12.3v is a failing battery, 12.8v is a new battery

Leave Black meter probe on battery negative
Touch Red Meter probe to B+ on alternator, B+ is on the back of the alternator and has stud/nut and larger wire.
Should read EXACTLY what battery reads, lets used 12.5v

Now move Black probe over to alternators metal case, leaving Red Probe on B+
Again should read EXACTLY what battery did.

Unplug 3 wire connector on alternator
Test Yellow wire with Red probe, Black probe on alternators case
EXACTLY battery volts

Test Green wire the same way, should be 0 volts

Turn key on
Test green wire again, should be withing .1 of battery volts, so if using 12.5 then 12.5 or 12.4v

If wires all test OK reconnect and start engine

Battery voltage should now read 14.2 to 14.9volts
Steady, no jumping around
Let engine idle for 3 or 4 minutes then test again, battery voltage should be under 14volts, 13.5 to 13.8v

If so all is well
 

PonyUp

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Still not right

Thanks Ron.

Had it hauled the next day and someone new put a 80 AMP in. He said the last one tested bad.
Still does same thing. Told guy about what you said and he said his computer would tell him. Guessing he was wrong or something made that one go instantly bad too? It dropped from 14 to 12 with a load. He said the parts hotline said it it supposed to do that. I say parts guy is wrong. I know my car. Never did any of this before. Won't be using that shop again.

Hauled it to a shop with electrical reputation. Tranny guy will not check tranny until this issue is fixed. Hopefully this shop will get it right. Wishing I could have waited but need my car back ASP. One and only daily driver. Guess I will be borrowing a car.

Thanks again Ron.
 

Denisefwd93

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Burnt tranny fluid??? My guess is your troubles are just beginning.

Don't know what to tell you about your alternator problems. Ron is sharp! if you take his advice you'll probably find a problem, but it looks like you would rather or pretty much have to go to a shop where you are at their mercy.

This is why I've made it a point to learn all I can about such things.

Hope it all works out for you!
 

RonD

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Computer to test voltage???

Charging systems are tested with volt meter and some common sense about how they work, which is not that complicated :)

Buy a volt meter or find a shop with "an old guy" who knows pre-2000 charging systems

If your voltage with engine running is 14v and it drops to 12v then voltage regulator is shutting off voltage to rotor, turning OFF the alternator
 
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PonyUp

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Ongoing...

Hey Guys...Thanks for responding.

I was in a bind as I live out in the country alone with just this one car. Then when tranny did what what it did, I did not want to drive it and not even delving into that arena. Hence it was towed and 80 AMP put on.

Since 80 AMP is doing exactly the same as the others, what are the odds of all 3 having bad regulators? Something is shorting them out? The guy who has the car now is in his 60's. He is pretty open to listening to my detailed drama. Will relay what you said about regulator and now>>Lesson learned. Ouch.
Should have taken original off and had it rebuilt. Now tranny is a issue.

Will let you know what shop owner says if/when they find something.

Thanks again guys.
 

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If it was my truck, I'd be looking for bad connections or cables.

It's a common problem that the connector at the alternator overheats and has problems. When I replaced my alt it actually came with a new connector. I'd be checking all the grounds, esp the negative cable from the battery to the frame and block. Run your fingers along the cables and feel for breaks or "squishy" spots. I've had a battery cable that corroded inside the insulation where you could not see it.

Don't overlook a wonky battery either, they don't always flat out die. You might have a cell that goes out intermittently.
 
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PonyUp

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Iac

Thanks Jerry. Battery is testing like new. Battery cables were replaced last year. All wires connecting to/from alternator are testing good. They will be putting a IAC on in morning and will go from there.

I am wondering if a bad alternator could have made it go out as I had no issues with RPM, Idle, AC compressor or tranny shifting issues until the first alternator was replaced.

Ordered 2 original repair manuals off ebay.
 

JerryC

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One thing you learn from experience, new doesn't always mean good. Another is that testing doesn't always catch every problem. :)

An ohm test of cable just shows continuity, a single strand of wire would show the cable as good even when the other strands in the cable are bad. Same with a voltage drop reading.

I would doubt that an IAC would be blown by a bad alternator. Not saying it isn't possible, just very unlikely.

The AC comp: You need to see the pressures to determine if it is low charge or electrical. Or a scope to watch the voltage.

One other thought, does your alternator ground to the block through the mount points to the engine? if so clean up those mount points so there will be a good connection.

The place that worked on it first, what kind of place are they? How likely is that they burned up your trans by beating on it? The kind of place where the youngest least experienced guy was assigned to work on it and he just simply broke things because he doesn't know what he is doing? If I worked on it, you wouldn't have gotten it back until I knew why the voltage dropped from 14 to 12 after I put an alternator on it. Or maybe they do know how all those problems came about after the alternator swap and they don't want you to know.

Hopefully this last guy will sort it out for you.
 

PonyUp

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Saga continues

Thanks Jerry. Got you on bad parts and wires/grounds. The first shop has been the place most people take their cars in this cool but podunk little city. He is insisting there was nothing wrong with either alternator. I have the last alternator he installed in a box and convinced him he will be refunding all costs along with a core charge. The transmission issues will also come back on him if there is damage due to the voltage drops. He has a couple of bad online reviews but I cannot see them doing anything intentional to the tranny even though he has a attitude. Minor parts maybe but Most laces around here won't even look at trannys. They send you to a tranny shop.

So, I got a call yesterday from the last shop, saying my car is ready. They said it was not dropping and idle/RPM was good. They installed the IAC and added 2 grounds. One ground does now go to bottom of engine block. The engine block is clean. (Brother took it out and replaced seals/gaskets and painted it silver so I would notice any leaks.) I pay them and the car was showing good RPM and needle was in middle of gauge for charge. I drive out headed for the tranny shop, go 2 blocks and turn AC on. The needle drops to almost red and RPMS are back down when I slowed car down. Headed back to shop and they tested it. Even with the just the lights turned on it, it dropped from 14 to 12.6. Car remains with them and though I trust them and trust they will figure it out eventually, I am certainly not a happy camper. Will keep you posted. Thanks again for the words, info, suggestions and Bronco support.
 

Denisefwd93

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How does a 1989 non-electronic transmission get affected by low voltage? Someone will need to explain that to me...

are all these rocket scientist and you using the gauge on the dashboard as your determination of voltage drop??

What do you actually turn on (or not) that causes the drop in voltage, is it the air conditioning ? because you mentioned the clutch doesn't stay in I'm thinking bad clutch, bad blower motor, and or resistor.

Both Rangers, ( I'm on my second one) , seem to have a heavy draw with the blower on high and it's hot outside. but I've not felt anything was wrong.
I've seen this in another Vehicles I've driven over the years also.
 
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JerryC

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Even with the just the lights turned on it, it dropped from 14 to 12.6. Car remains with them and though I trust them and trust they will figure it out eventually, I am certainly not a happy camper. Will keep you posted. Thanks again for the words, info, suggestions and Bronco support.
It only takes a couple of minutes to slap a different battery in it for a test. Just saying...
 

RonD

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Charging system is not all that complicated, surprised about this ongoing issue

Battery voltage, engine off, I assume is 12.6v
With engine running, alternator takes over and system voltage will be above 13.5v
If at anytime when engine is running, and the system voltage drops to 12.6v then alternator is OFF or is disconnected from the vehicles electrical system.

This can be B+ terminal on alternator, or wire from B+ to Power distribution post(starter relay).
OR
Voltage regulator has cut voltage to alternators rotor, turning alternator OFF

Unlikely but possible is that the Alternators bracket is not a good Ground, or Battery's Negative cable to Engine is not a good Ground
Some do run a ground strap or cable from alternator bracket to Batteries ground cable on the engine or to other known good ground point
Bad ground for alternator and/or voltage regulator turn alternator OFF
 

PonyUp

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Ongoing...

Battery has been tested by 4 people as being good. All wires to/from alternator/battery tested good. Two more grounds added. Just turning on headlights can make it drop to 12.6. It is not just the AC making it happen. No one is using just the dash gauge to say there is a voltage drop issue. 3 shops have verified the drop using their equipment. And yes, the transmission gets info from the computer. Electronic communication. Maybe I am missing something here but I am thinking the computer is central information center to all of the electronic components. Proper voltage is required for everything to work as it should?

Shop said all was fine before I went to pick it up. I drive 2 blocks and it is not. Take it back to shop and leave it after they verified indeed it was doing the same voltage drop by just turning on headlights. Dropped to 12.6. Called yesterday and they said they started it backup, drove it and it was reading as it should. They are trying to track down why it does what it should then it won't. They are saying it is still idle issue even after replacing the IAC and adding 2 grounds.

The good news is they are not charging for any further diagnostic testing. $450 later>>I guess not.
 

Denisefwd93

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Does this actually mean what it says??????

"The engine block is clean. (Brother took it out and replaced seals/gaskets and painted it silver so I would notice any leaks.)". ???

This may be when your electrical problems started, maybe not right away but not long after...

dollars to Donuts, you have a pinched, burned, scraped, wire/s, connections, connectors, PCM heat sink, capacitors, etc

The alternator on my truck was overheating so hot, I could smell the burning varnish on the copper windings inside.

I'm not one to just throw parts at a truck, I needed to know why the alt was overheating.

Eventually I found the harness on my bank one oxygen sensor was pinched between the engine block and the bellhousing from when we swapped out the transmission! I was told; "no, that wouldn't cause that" but it cleared up after it was fixed and alternator was replaced with new,

Apparently, this a very common problem with do-it-yourself people getting wires pinched between engines and m bellhousings.

your problem only happens when the truck is moving, which also would indicate something is pinched or in a situation where it only shorts out when the truck is moving.

Ron is spot-on, electrical is rather simple on Automotive but the same principles apply to all electricity

It may be time for you to do some self education because you are in a tough situation, spending big money find out nothing. When you finally do find a problem you're going to feel very foolish, I know I did.

Some additional reading
https://www.fluke.com/en-us/learn/blog/automotive/electrical-automotive-troubleshooting
 
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