Alternator Output?
Thread Starter
Senior Member
Joined: Nov 2012
Posts: 177
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Alternator Output?
Bought a '90 F-150, 140K, 5.8L, E4OD, A/C blew hot air, compressor covered with oil, gambled on leak being shaft seal, bought new compressor, nice working A/C now BUT:
At idle, dashboard gauge shows voltage way down with blower on high or next lower speed. A/C off, gauge always shows OK. Headlights draw it down even more with A/C on.
I THINK the alternator is trying to tell me something. Shouldn't voltage at idle be acceptably high with accessories on? Alternator brushes barely making contact anymore? No noise. Serpentine belts don't slip.
Do they still sell alternator rebuild kits? Anyone know what the alternator rating would be in this truck? Thanks for help! imp
At idle, dashboard gauge shows voltage way down with blower on high or next lower speed. A/C off, gauge always shows OK. Headlights draw it down even more with A/C on.
I THINK the alternator is trying to tell me something. Shouldn't voltage at idle be acceptably high with accessories on? Alternator brushes barely making contact anymore? No noise. Serpentine belts don't slip.
Do they still sell alternator rebuild kits? Anyone know what the alternator rating would be in this truck? Thanks for help! imp
Senior Member
Joined: Aug 2010
Posts: 959
Likes: 30
From: Belmont, Ms
Take the truck or pull the alternator and go to Autozone they can check the charging system or alternator.
It should be putting out at least a steady 13.9 volts. More than likely the regulator is bad it can be replaced. But you might be better off to get a new alternator, if you go with the Autozone route go with the one with the lifetime warrenty
It should be putting out at least a steady 13.9 volts. More than likely the regulator is bad it can be replaced. But you might be better off to get a new alternator, if you go with the Autozone route go with the one with the lifetime warrenty
Thread Starter
Senior Member
Joined: Nov 2012
Posts: 177
Likes: 8
Take the truck or pull the alternator and go to Autozone they can check the charging system or alternator.
It should be putting out at least a steady 13.9 volts. More than likely the regulator is bad it can be replaced. But you might be better off to get a new alternator, if you go with the Autozone route go with the one with the lifetime warrenty
It should be putting out at least a steady 13.9 volts. More than likely the regulator is bad it can be replaced. But you might be better off to get a new alternator, if you go with the Autozone route go with the one with the lifetime warrenty
Thread Starter
Senior Member
Joined: Nov 2012
Posts: 177
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November 2011 TOTM Winner
Joined: Apr 2011
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From: Dallas area
2G- 2nd generation, 3G- 3rd generation and I think now Ford is up to 6th. Below is a basic description from RJM, they sell 3G kits. Bottom line is 2G is a fire hazard and couldnt carry the load, 3G is a vast improvement and with varying amperage ratings available, you can customize your power needs with an alternator that will handle it.
Here's my 3G install thread:
https://www.f150forum.com/f10/3g-altenator-165829/
http://oldfuelinjection.com/?p=75
In 1996 Ford publicly recognized the fire hazard caused by the 2G alternator and released TSB 96214. This alternator design caused increased resistance and heat which could damage the wire harness and alternator. A small percentage of vehicles actually caught on fire!
Fords 3G alternator was a giant leap in technology and quality. The 3G was internally regulated, used two internal cooling fans, sealed bearings, and had a superior battery stud. The 3G’s were more efficient, and produced more amperage at idle than any of its predecessors.
Here's my 3G install thread:
https://www.f150forum.com/f10/3g-altenator-165829/
http://oldfuelinjection.com/?p=75
In 1996 Ford publicly recognized the fire hazard caused by the 2G alternator and released TSB 96214. This alternator design caused increased resistance and heat which could damage the wire harness and alternator. A small percentage of vehicles actually caught on fire!
Fords 3G alternator was a giant leap in technology and quality. The 3G was internally regulated, used two internal cooling fans, sealed bearings, and had a superior battery stud. The 3G’s were more efficient, and produced more amperage at idle than any of its predecessors.