• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

1996 4.0 Overcharging


Jim Oaks

Just some guy with a website
Administrator
Founder / Site Owner
Supporting Vendor
Article Contributor
TRS Banner 2010-2011
TRS Banner 2012-2015
TRS 20th Anniversary
VAGABOND
TRS Event Participant
GMRS Radio License
Joined
Aug 2, 2000
Messages
13,407
Reaction score
8,527
Points
113
Location
Nocona, Texas
Vehicle Year
1996 / 2021
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
4.0 / 2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
6-inches
Tire Size
33x12.50x15
A while back my 1996 Ranger 4.0 had a problem on the trail with the battery smoking from being overcharged.

I replaced the alternator with a used one.

Recently the problem happened again. The Ranger wouldn't restart when I shut it off and the battery was boiling from being overcharged.

It seems like there has to be something other than just a bad alternator causing this since it's happened again.

I need to figure out what it is instead of just getting another alternator and frying another battery.

Anyone have any suggestions?
 


Jspafford

Logan Andrew Feb 17, 2012
V8 Engine Swap
TRS Banner 2010-2011
Joined
Jan 2, 2001
Messages
8,012
Reaction score
15
Points
38
Age
40
Location
Lancaster, Ohio
Vehicle Year
2016
Make / Model
Chevy 3500HD
Engine Type
V8
Engine Size
6.6L
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
5"
Tire Size
35"
Are you sure it is overcharging and not grounding out on something?

Have you verified the alternator is putting out the proper voltage?

The alternator is the only thing that charges the battery. The voltage regulator is built into the alternator. I would check the voltage output from the alternator with a meter both at idle and at 2K RPM. It should be no higher than 14.5 or so volts.
 

engdept

New Member
Joined
Jun 17, 2008
Messages
652
Reaction score
5
Points
0
Age
39
Location
Charlestown, IN
Vehicle Year
1989
Make / Model
Ford
Engine Size
2.9
Transmission
Manual
or just take the alternator to an auto parts store and have them test it
 

Quiksurf

New Member
Joined
Jul 3, 2008
Messages
68
Reaction score
0
Points
0
Location
Southern NJ
Vehicle Year
1995
Make / Model
Ford
Engine Size
3.0
Transmission
Manual
you are missing the most important part, the alternator does not sense the volatge on the b+ feed, check for key on engine off (KOEO) battery light illumination, the check the violet/white wire a the alternator for battery voltage. if you have a lower voltage than the battery should have it will increase the feild output of the alternator creating more voltage. possibly the cause of your issue or just another junk part
 

Will

Forum Staff Member
TRS Forum Moderator
Joined
Nov 30, 2001
Messages
6,925
Reaction score
514
Points
113
Location
Gnaw Bone, Indiana
Vehicle Year
2007
Make / Model
Toyota
Engine Size
4.0
Transmission
Manual
I agree with Quiksurf--you replaced a good alternator. The alternator is sensing a low voltage and trying like hell to charge the battery that is already charged.

On these alternators the regulator looks at a voltage at the A terminal on the alternator. That wire runs into the power distribution and probably has a 15-amp fuse or breaker. Mine is Yellow/White. Make sure your wire is intact. Read that voltage while the truck is running and compare it to the battery voltage. If it's a lot different, there's higher than normal resistance in that wire and that's a problem.

The idiot light senses voltage and it could be in the normal range and still be overcharging the battery.

This truck has a remote battery doesn't it? What did you change when you moved it? Is there a solenoid or something added somewhere?

Keep in mind this truck probably has a lot more of an alternator than TRS-1, and that 2 batteries can absorb a lot more current than one. You might not notice the overcharging with 2 batteries but one battery could quickly become fried. And with probably 2x or more the alternator of TRS-1, just because the way you have it set up on the old truck doesn't mean it will be acceptable on this one.
 

Bob Ayers

New Member
Joined
Aug 28, 2007
Messages
2,274
Reaction score
16
Points
0
Location
Durham, NC
Vehicle Year
1999
Make / Model
Ranger
Transmission
Automatic
you are missing the most important part, the alternator does not sense the volatge on the b+ feed, check for key on engine off (KOEO) battery light illumination, the check the violet/white wire a the alternator for battery voltage. if you have a lower voltage than the battery should have it will increase the feild output of the alternator creating more voltage. possibly the cause of your issue or just another junk part

According to my schematics for a 1997, the wire from the alternator "A" terminal is a YEL/WHT, and is fused with fuse #6 (15A) in the engine compartment fuse box.
 

Jim Oaks

Just some guy with a website
Administrator
Founder / Site Owner
Supporting Vendor
Article Contributor
TRS Banner 2010-2011
TRS Banner 2012-2015
TRS 20th Anniversary
VAGABOND
TRS Event Participant
GMRS Radio License
Joined
Aug 2, 2000
Messages
13,407
Reaction score
8,527
Points
113
Location
Nocona, Texas
Vehicle Year
1996 / 2021
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
4.0 / 2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
6-inches
Tire Size
33x12.50x15
I'm set up for (2) batteries in the bed, but there is only one in there. The other is in the other Ranger.

My truck has the factory charging gauge and it's in the normal range.

My battery is dead. I didn't want to put another battery in because I didn't want to fry the only battery I have left.
 

Will

Forum Staff Member
TRS Forum Moderator
Joined
Nov 30, 2001
Messages
6,925
Reaction score
514
Points
113
Location
Gnaw Bone, Indiana
Vehicle Year
2007
Make / Model
Toyota
Engine Size
4.0
Transmission
Manual
The alternator is fine, that's why the gauge is reading normally.

The alternator is being given a false input so it cannot properly adjust it's output--but it's not putting out a voltage outside the expected range.

It's not capable of burning up your battery by connecting it and running the engine for a few minutes. Get a real voltmeter ready, start it and test the battery voltage. It's going to read 15-16V probably because it thinks the battery is discharged. Then poke the A terminal and it's going to read something less than 13V I believe. Then turn off the truck because you know what the problem is.

Then trace that wire and see what is causing the resistance. I would unplug it, pull the fuse and put your ohmeter probes on each end. Or jump it straight to the hot side of the starter relay and start the truck again. If there is a problem, the voltage will now be very similar between the A and the B+.
 
Last edited:

Jim Oaks

Just some guy with a website
Administrator
Founder / Site Owner
Supporting Vendor
Article Contributor
TRS Banner 2010-2011
TRS Banner 2012-2015
TRS 20th Anniversary
VAGABOND
TRS Event Participant
GMRS Radio License
Joined
Aug 2, 2000
Messages
13,407
Reaction score
8,527
Points
113
Location
Nocona, Texas
Vehicle Year
1996 / 2021
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
4.0 / 2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
6-inches
Tire Size
33x12.50x15
Ok.

I replaced the voltage regulator. No change.

I checked the 'A' terminal. It has 12 volts and there isn't any loss through the line with an ohm meter.
 

Will

Forum Staff Member
TRS Forum Moderator
Joined
Nov 30, 2001
Messages
6,925
Reaction score
514
Points
113
Location
Gnaw Bone, Indiana
Vehicle Year
2007
Make / Model
Toyota
Engine Size
4.0
Transmission
Manual
12.0v with it running? What was the output to the battery with it running? How different were they?
 

Jim Oaks

Just some guy with a website
Administrator
Founder / Site Owner
Supporting Vendor
Article Contributor
TRS Banner 2010-2011
TRS Banner 2012-2015
TRS 20th Anniversary
VAGABOND
TRS Event Participant
GMRS Radio License
Joined
Aug 2, 2000
Messages
13,407
Reaction score
8,527
Points
113
Location
Nocona, Texas
Vehicle Year
1996 / 2021
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
4.0 / 2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
6-inches
Tire Size
33x12.50x15
Alright.

I'm starting to think this alternator is putting out exactly what is suppose to.

According to my Chiltons book, it should be putting 14.1-14.7 volts out at the battery when it's running.

I didn't check the 'A' running.
 

Will

Forum Staff Member
TRS Forum Moderator
Joined
Nov 30, 2001
Messages
6,925
Reaction score
514
Points
113
Location
Gnaw Bone, Indiana
Vehicle Year
2007
Make / Model
Toyota
Engine Size
4.0
Transmission
Manual
I just started mine and I got 14.6 off both. I would run a jumper right to the terminal if you can and see. Poke a jumper wire right down in the back of the connecter on the alternator.
 

Bob Ayers

New Member
Joined
Aug 28, 2007
Messages
2,274
Reaction score
16
Points
0
Location
Durham, NC
Vehicle Year
1999
Make / Model
Ranger
Transmission
Automatic
Alright.

I'm starting to think this alternator is putting out exactly what is suppose to.

According to my Chiltons book, it should be putting 14.1-14.7 volts out at the battery when it's running.

I didn't check the 'A' running.

Put a UDP on it Jim, that will bring that charging voltage down!!:D:D:D:D
 

Jim Oaks

Just some guy with a website
Administrator
Founder / Site Owner
Supporting Vendor
Article Contributor
TRS Banner 2010-2011
TRS Banner 2012-2015
TRS 20th Anniversary
VAGABOND
TRS Event Participant
GMRS Radio License
Joined
Aug 2, 2000
Messages
13,407
Reaction score
8,527
Points
113
Location
Nocona, Texas
Vehicle Year
1996 / 2021
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
4.0 / 2.3 Ecoboost
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
6-inches
Tire Size
33x12.50x15
OK!

Back to the original problem.....

The battery was boiling and went dead from what I thought was overcharging. Could the battery have taken a dump from all the vibration being shook around off road? The battery is 8-years old.
 

Bob Ayers

New Member
Joined
Aug 28, 2007
Messages
2,274
Reaction score
16
Points
0
Location
Durham, NC
Vehicle Year
1999
Make / Model
Ranger
Transmission
Automatic
OK!

Back to the original problem.....

The battery was boiling and went dead from what I thought was overcharging. Could the battery have taken a dump from all the vibration being shook around off road? The battery is 8-years old.
Either that, or you developed a "short" somewhere in your electrical system, and the battery was boiling from being discharged.
8 years out of a battery is outstanding!
 

Sponsored Ad


Sponsored Ad

Staff online

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Kirby N.
March Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top