Need a Charging Sys Expert - I've got a "twitchy" Amp guage ... sometimes.

[PetroleumJunkie412]

Alternator should NEVER go above 14.9volts, higher than 15volts will ruin a 12volt battery, hence the flashing light

Engine running it should NEVER go below 13.5volts, hence the jumping gauge

So you have a voltage regulator issue, regardless of its age, actually I would replace the whole alternator, bad diode on a Field could cause the 15+ volts

THE LORD HAS SPOKEN ??

 

[Rusty Bouquet]

Based on your posts, I would agree that a diode is failing in your alt.. That's not unusual for any age on an alt.. They don't test the individual diodes before installing them, and they are likely all from china these days. If you want to, you can tear it down and test each one. They're not hard to replace either. I can usually rebuild one in an hour, if I don't clean and paint it.

 

[cobrajocky]

I've noticed that while the engine is still in a warm-up stage at night (within 2 - 3 minutes of start-up}, the headlights are pulsating (matching the "twitching" of the Amp gauge when in low-beams. It was only that one time after sitting for a couple colder days / nights that the alternator output was grossly above 15volts only on startup. Today, the Alt output on the volt "Reader" adapter, it only hit 15v for a few seconds and then stayed below and in the 14.5 to 14.8v. The battery shows holdng a 12.9 to 13v charge for a couple of hours after the engines off. 12.4 to 12.5v overnight on a cool 40's evening left outside.

I've been around cars and trucks, building racing engines all my life. My dad worked for Ford Truck Div as Engineering VP for more than a decade and then left to own several dealerships including the Cobra franchise for ILL, Indiana, Iowa and Wisconsin in the early 60's. I can't remember a Rectifier just suddenly going bad like this in recent decades, especially in a vehicle barely used - Alts yes (brushes, windings, bearings). Have several friends with Rangers, lots of miles and years and none had a rectifier go bad this suddenly? Again this is a 1997 (Ranger XLT) Mazda B-4000SE Extra cab 2WD

I've searched online for Alt Voltage Rectifiers, I've seen ones that cost as much as a whole Alternator new (with one) and some in the $40 range. I hesitate to pop for just a rectifier and have it be the Alt.

 

[RonD]

I would go to a wrecking yard and get a used one, whole alternator, see if that solves the problem

A used Ford alternator is better than a new, 3rd party brand, IMO
You have a 95amp, but can get a 115 or 130 amp from a later model Ranger

What fits seen here: https://therangerstation.com/tech_library/alternator.shtml

If you have a Volt meter set if for AC volts and test battery with engine running, should show under .5vAC, if higher then diode issue

 

[cobrajocky]

I would go to a wrecking yard and get a used one, whole alternator, see if that solves the problem

A used Ford alternator is better than a new, 3rd party brand, IMO
You have a 95amp, but can get a 115 or 130 amp from a later model Ranger

What fits seen here: https://therangerstation.com/tech_library/alternator.shtml

If you have a Volt meter set if for AC volts and test battery with engine running, should show under .5vAC, if higher then diode issue

Are you kidding? This is the People's Republic of Kalifornicate; wrecking yards were banned a couple of decades ago, along with coal, Nuclear Energy, Republicans, plastic bags, straws and freedom. Not kidding, there are NO wrecking yards anymore, nowhere, not even in slightly less Socialist So Kal.

When I was a kid in the 70's racing Mustangs at Laguna Seca and Sears Point, we spent weekdays at junkyards (er Auto Recycling depots) picnicking the wife and kids.

Online wrecking yards (from mostly back east) are a total ripoff and you have no idea what the heck (ell) will show up at 300% more than it's worth.

I'll do those tests as soon as possible. Thanks for the link, I've already been scouting on the net to Alts and Diode Rectifiers.

 

[RonD]

Oops, I meant "previously tested automotive parts recycling yards", lol.

I grew up in Riverside Calif.
One of my friend's Dad own a "wrecking yard" and we used to work as yard monkeys pulling parts and generally having a good ol' time in a teenage boy paradise of old cars that you could wreck.............again,

Sorry to hear that entry level mechanics field is gone in Calif.

 

[cobrajocky]

The south of Riverside area, ones in San Berdo, Corona, down in Imperial Co are all gone. Used to be lots of "wrecking yards up in Sunland (NE of downtown LA if you remember where that is (was a Hells Angel's area, lots of "chop shops"), now all gone. Old cars and trucks for scrap are hauled to Nevada or Aridzonia-kittylitter-land now for scrapping and parting out.

I know what you mean about that on the job wrecking mechanics "job training" in wrecking yards. I grew up on a huge family farm in Nor Central Illinois 58 families all retated from grandparents, their brothers and sisters, nephews, nieces, cousins to 4th cousins, etc like the massive farms in central Europe. On a big farm the "wrecking yard" is the "back 40" behind all the barns and silo's 'cause farmers NEVER throw away anything, you might need it fer somethin' someday. My first truck was a '48 Willy's PuP in 1962 (freshman in HS) with many parts from Studebakers, other Willy's International Harvester PuP's and Fords, etc. "harvested" from the farms back 40. I put a 1950 Ford 255ci Flathead V8 with a Holly quad in it from a Ford Delivery truck that a combine hit on the road on a thick early foggy morning on a spur road near the farm. nearly tore the truck in half, not a dent on the Combine, just some scratches. That 255 ford Flathead started me on building race motors and transmissions at 14 years old. I left the electrics, suspensions and brakes to others to learn.

Maybe I'll look for a pulled complete Alternator online to rebuild myself, how late a model Ranger Alt will fit and work on a 1997-1999? ..... I did know that the originals are only rated to about 95amps.

Any tips on where to find good Alternator rebuild parts at bargain prices?

 

[RonD]

I too had a Willys as my first car, I was 15 years old, 1955 willys overlander station wagon 4x4, super hurricane flat head 6, was junked by Riverside water department, engine was laying in the back, paid $100, got it running for my 16th birthday

I think Ranger, Mazda B-series up to 2003 would be fine, or Explorer up to 2001
A higher AMP alternator is good and you don't need to change the B+ wire or fuses, UNLESS you will be adding more electrics
If your stock system draws, say 45amps, with everything on then thats all any size alternator will output, a 200amp alternator "can" output 200amps, but it doesn't unless the electrics NEED 200amps

But a higher rated alternator can make more amps at idle, i.e. 60% of 115 is more than 60% of 80

 

[MTZ]

I have a similar issue, but the battery light doesn't flicker, it stays on, when it does come on.
My truck, 2007 Ranger XLT 2.3l Auto, has 220K with Original Alternator, so maybe its time to change it, but I dont want to if I dont have to.

I'm looking for loose or corroded connections, but not finding them.
Is there a Fusible Link in this system or a Fuse, if so, where is it.

 

[RonD]

I have a similar issue, but the battery light doesn't flicker, it stays on, when it does come on.
My truck, 2007 Ranger XLT 2.3l Auto, has 220K with Original Alternator, so maybe its time to change it, but I dont want to if I dont have to.

I'm looking for loose or corroded connections, but not finding them.
Is there a Fusible Link in this system or a Fuse, if so, where is it.

Yes, 2 Fusible links, no other fuses, but pretty easy to test if a fusible link is bad
Test with Key OFF
2007 Alternator will have Red wire on B+, larger terminal on alternator
Use alternator case as the ground and test if it has Battery Voltage, test battery first, should match exactly
If voltage looks good then fusible link is good

Then unplug voltage regulator connector
Test its Red wire, should also have battery voltage, if so then its fusible link is OK

You can also test grey wire, its the battery light wire, 0volts key off, Battery volts key on, can be .1-.2 less thats OK

If voltage tests OK then vehicle wiring is OK, alternator is bad

 

[cobrajocky]

RonD - The "Fluctuation" with the Alternator on my Mazda B-4000 is still going on, though it rarely jumps above 15V on startup. I've been shopping around for a replacement Alternator w/Voltage Reg, trying to find one with the higher amperage output of 95A and I found this one new made by TYC that is compatible with my 4.0L V6 model and up to F-150's. Do you have any input on these TYC Alts? I have to assume that they are Chinese, but are any made in the US or Japan anymore that isn't a couple of hundred bucks? I'm on a tight (retired) budget. Thanks a ton for all your replies and advice.

Oh forgot to ask, this Alternator has a 6S Pully, I'm not sure if the stock pully on the B4000 / Ranger XLT 4.0L is the same?

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[MTZ]

Yes, 2 Fusible links, no other fuses, but pretty easy to test if a fusible link is bad
Test with Key OFF
2007 Alternator will have Red wire on B+, larger terminal on alternator
Use alternator case as the ground and test if it has Battery Voltage, test battery first, should match exactly
If voltage looks good then fusible link is good

Then unplug voltage regulator connector
Test its Red wire, should also have battery voltage, if so then its fusible link is OK

You can also test grey wire, its the battery light wire, 0volts key off, Battery volts key on, can be .1-.2 less thats OK

If voltage tests OK then vehicle wiring is OK, alternator is bad

Thanks RonD, Tested the alt. like you suggested and got same voltage reading at the Alt as at the battery.
Put in a new (remanned) alt. last Sunday and havent seen the light since.

 

[RonD]

Thanks RonD, Tested the alt. like you suggested and got same voltage reading at the Alt as at the battery.
Put in a new (remanned) alt. last Sunday and havent seen the light since.

Good work

 

[RonD]

RonD - The "Fluctuation" with the Alternator on my Mazda B-4000 is still going on, though it rarely jumps above 15V on startup. I've been shopping around for a replacement Alternator w/Voltage Reg, trying to find one with the higher amperage output of 95A and I found this one new made by TYC that is compatible with my 4.0L V6 model and up to F-150's. Do you have any input on these TYC Alts? I have to assume that they are Chinese, but are any made in the US or Japan anymore that isn't a couple of hundred bucks? I'm on a tight (retired) budget. Thanks a ton for all your replies and advice.

Oh forgot to ask, this Alternator has a 6S Pully, I'm not sure if the stock pully on the B4000 / Ranger XLT 4.0L is the same?

Alternator 95A TYC For Ford E F-Class Ranger Mazda B2300-B4000 Mercury Tracer | eBay

Find many great new & used options and get the best deals for Alternator 95A TYC For Ford E F-Class Ranger Mazda B2300-B4000 Mercury Tracer at the best online prices at eBay! Free shipping for many products!

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No, I haven't used them
Most parts usually have some reviews, even if its just a few good ones its a good sign, people usually only bother to post bad reviews, lol, so just a few bad reviews and a few good ones is a GOOD sign

 

[cobrajocky]

No, I haven't used them
Most parts usually have some reviews, even if its just a few good ones its a good sign, people usually only bother to post bad reviews, lol, so just a few bad reviews and a few good ones is a GOOD sign

Does the stock 4.0L V6 Ranger or Mazda B-4000 Alternator us a "6S Pully"? Seems most of the 95A Alts I've looked at use a 6S Pully. If not, is it possible to swap what on my OEM onto this TYC or any other "New" compatible alternator?