Wonky Charging / Electrical output
Thread Starter
|
Senior User
Joined: May 2013
Posts: 327
Likes: 0
From: Flaherty, KY
Wonky Charging / Electrical output
For some reason the voltage fluctuates wildly at idle or slightly above, but seems to return to normal at higher engine speeds.
When I first start the truck cold, at night you can see the change in voltage in the headlights, they almost resemble a strobe light, alternating quickly between bright and dim. I can see it on the ammeter, it bounces around from a little under 1/2, to about 3/4 on the gauge.
Once I go faster than about high idle, the problem disappears, so while driving the truck it isn't an issue. But mildly embarrassing when I stop at a light or something and I'm flashing at the car in front of me if I don't keep my foot on the gas.
Some have suggested I switch to a 3G alternator, however I'm not sure I know the difference or why the swap is recommended. Is there something wrong with the alternators in these trucks, or is this a common issue?
Thanks all for the help/suggestions/input.
When I first start the truck cold, at night you can see the change in voltage in the headlights, they almost resemble a strobe light, alternating quickly between bright and dim. I can see it on the ammeter, it bounces around from a little under 1/2, to about 3/4 on the gauge.
Once I go faster than about high idle, the problem disappears, so while driving the truck it isn't an issue. But mildly embarrassing when I stop at a light or something and I'm flashing at the car in front of me if I don't keep my foot on the gas.
Some have suggested I switch to a 3G alternator, however I'm not sure I know the difference or why the swap is recommended. Is there something wrong with the alternators in these trucks, or is this a common issue?
Thanks all for the help/suggestions/input.
Thread Starter
|
Senior User
Joined: May 2013
Posts: 327
Likes: 0
From: Flaherty, KY
Oops, sorry- it's a 1985 F250 4x4 with carbureted 460. No idea if there's a separate regulator. I see there's an ignition module or something on top of the driver's side fender, but I see nothing else resembling one.
Posting Guru
Joined: Aug 2009
Posts: 2,271
Likes: 2
From: Mexia, TX
1G - First Generation alternator, what the early 80s trucks had. Has like five or so wires connected to the back, usually bolt-on lugs. Externally mounted voltage regulator is on the passenger side inner fender by the starter solenoid.
2G - Second Generation alternator, these were on the later 80-86 trucks. These have two or three connections on them and they have a plug-in connector compared to the bolt-on lugs the 1G has. Internally mounted voltage regulator
3G - Third Generation alternator. Our trucks never came with these. They're usually from other Ford vehicles and put out way more than ours ever did (130 amps usually). There's usually some custom wiring involved when installing one of these, and you'll have to change the pulley if you have V-belts, but it's not difficult. Internally regulated.
What year is your truck?
I would suspect the alternator or the voltage regulator. Usually you can take them both to an auto store and they'll check them for you. Sometimes they can check them in the vehicle.
I personally haven't had any issues with the OE-style alternator in my truck, aside from just the fact that it's only 65 amps. A good alternator and regulator will put out steady voltage.
The 3G alternators are nice because they put out almost as many amps at idle as our stock ones do at full output.
2G - Second Generation alternator, these were on the later 80-86 trucks. These have two or three connections on them and they have a plug-in connector compared to the bolt-on lugs the 1G has. Internally mounted voltage regulator
3G - Third Generation alternator. Our trucks never came with these. They're usually from other Ford vehicles and put out way more than ours ever did (130 amps usually). There's usually some custom wiring involved when installing one of these, and you'll have to change the pulley if you have V-belts, but it's not difficult. Internally regulated.
What year is your truck?
I would suspect the alternator or the voltage regulator. Usually you can take them both to an auto store and they'll check them for you. Sometimes they can check them in the vehicle.
I personally haven't had any issues with the OE-style alternator in my truck, aside from just the fact that it's only 65 amps. A good alternator and regulator will put out steady voltage.
The 3G alternators are nice because they put out almost as many amps at idle as our stock ones do at full output.
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
Likes: 11
From: Exmore, VA
1G - First Generation alternator, what the early 80s trucks had. Has like five or so wires connected to the back, usually bolt-on lugs. Externally mounted voltage regulator is on the passenger side inner fender by the starter solenoid.
2G - Second Generation alternator, these were on the later 80-86 trucks. These have two or three connections on them and they have a plug-in connector compared to the bolt-on lugs the 1G has. Internally mounted voltage regulator
3G - Third Generation alternator. Our trucks never came with these. They're usually from other Ford vehicles and put out way more than ours ever did (130 amps usually). There's usually some custom wiring involved when installing one of these, and you'll have to change the pulley if you have V-belts, but it's not difficult. Internally regulated.
What year is your truck?
I would suspect the alternator or the voltage regulator. Usually you can take them both to an auto store and they'll check them for you. Sometimes they can check them in the vehicle.
I personally haven't had any issues with the OE-style alternator in my truck, aside from just the fact that it's only 65 amps. A good alternator and regulator will put out steady voltage.
The 3G alternators are nice because they put out almost as many amps at idle as our stock ones do at full output.
2G - Second Generation alternator, these were on the later 80-86 trucks. These have two or three connections on them and they have a plug-in connector compared to the bolt-on lugs the 1G has. Internally mounted voltage regulator
3G - Third Generation alternator. Our trucks never came with these. They're usually from other Ford vehicles and put out way more than ours ever did (130 amps usually). There's usually some custom wiring involved when installing one of these, and you'll have to change the pulley if you have V-belts, but it's not difficult. Internally regulated.
What year is your truck?
I would suspect the alternator or the voltage regulator. Usually you can take them both to an auto store and they'll check them for you. Sometimes they can check them in the vehicle.
I personally haven't had any issues with the OE-style alternator in my truck, aside from just the fact that it's only 65 amps. A good alternator and regulator will put out steady voltage.
The 3G alternators are nice because they put out almost as many amps at idle as our stock ones do at full output.
Moderator
Joined: Jan 2001
Posts: 57,012
Likes: 2,750
From: Virginia
The 1G is a good setup if you don't need the amperage(most people don't). If your truck has the 1G, it will have a regulator usually mounted on the pass side fender. If this regulator has a poor ground, it can cause the flickering like you describe.
If you have the 2G(the one with two black/orange wires side by side) check the connectors, especially the two large side by side wires. These like to melt and cause a poor connection.
If you have the 2G(the one with two black/orange wires side by side) check the connectors, especially the two large side by side wires. These like to melt and cause a poor connection.
Thread Starter
|
Senior User
Joined: May 2013
Posts: 327
Likes: 0
From: Flaherty, KY
So based on the descriptions, I have a 1G alternator, despite the truck being an '85. I didn't see any loose connections at quick glance.
Guess I'll have the voltage regulator and alternator tested; might consider the 3G swap if one or both are bad.
Guess I'll have the voltage regulator and alternator tested; might consider the 3G swap if one or both are bad.
Trending Topics
Postmaster
Joined: Feb 2011
Posts: 3,560
Likes: 1
with junkyard parts, a 3g swap can be done for under $40. i did it in my 83 just because i was bored one night and had the parts on hand.
your pic does confirm that you have a 1g. it seems to me that the biggest problem with the 1g is the connections relating to the regulator.
if you go 3g, there are plenty of threads on the subject, including a couple down in the electrical forum with my name on them. its pretty simple if you're comfortable with basic wiring
your pic does confirm that you have a 1g. it seems to me that the biggest problem with the 1g is the connections relating to the regulator.
if you go 3g, there are plenty of threads on the subject, including a couple down in the electrical forum with my name on them. its pretty simple if you're comfortable with basic wiring
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 6 Best Deals Available on New Fords & Lincolns Right Now
Brett Foote
This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level
Verdad Gallardo
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Thread
Thread Starter
Forum
Replies
Last Post
fordtough81
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
11
Aug 1, 2015 10:55 PM
packrat56
1948 - 1956 F1, F100 & Larger F-Series Trucks
15
Sep 28, 2014 10:16 PM