Alternator ?

[Tree Killer]

Its been a while since i've messed with a alt. Does this sound right to u ? The voltage at the batt. and alt. at idle is 12.56. @ 2500 rpms its 13.60. I just replaced the batts. 2 days ago, the other ones were on their way out and the plowing season is here. to me it seems the idle volts should be higher. Thanks

[ShawnCT450R]

When you replaced the Batts, did you use a charger to fully charge them? Should always do this with new batts. I haven't ever seen voltage increase due to an increase in RPMs. Thats my limited experience though. I have seen a battery voltage of
14.something at idle so it sounds a bit low to me. Maybe a tech will chime in with more reliable info for you. If it was me, I would take it to napa or schucks or wherever and have them do the alternator test. They'll do it for free. Make sure your batteries are charged before you take it to them if you do. Low batts give the tester a fit, from what I was told. Hope this helps. Let us know what you find out.

[jfines@cox.net]

Make sure your glow plugs aren't active. That would cause low voltage. Other than that. I would take the altenator and have it checked at an auto parts store. Sounds low to me.

[bigcountrysg]

If your glowplugs are not being cycled when you checked out your charging system. Then your alternator is weak and will need to be changed soon. Your weak batteries could have damaged the alternator by over working it. Alternator output is around 14 volts. If your getting a low reading 12.5 volts at idle then your alternator is on its way out the door too.

[Fordinator]

Alternators will only output their rated current when cold. Also when you motor is at idle the alternator will output even less. I know my 05 has a 130 amp alternator, when hot and at an idle it may only output 25-35 amps.

To really verify your alternator you need a clamp on current meter on the main power line between the alt and the battery. If the current is less than 25 amps and you still have low voltage readings you most likely have a bad alternator. Also you should try and turn most of your accessories off, that blower fan can really suck a lot of juice.

[Tree Killer]

I'll have to go to Auto Zone, and have them test it. The dealer said its a 110 amp unit. That seems low too, Wrangler NW - Power Products these guys have a 150 amp for 400.00$ Its not listed on their site but I called. The stock one from Ford is 310.00$. Auto Zone has one for 230.00$ with a lifetime warrenty. Carquest was 186.00$ How would I know if the glow plugs were cycling? The light is not on ? Thanks for the replies

[Tree Killer]

Took it Advance Parts, (Auto Zones tester was broke) @ idle it pushed 4.0 amps @ 2000rpms 16amps 13.30 Vs. anyone know how to test for the glow plug cycling thing?

[Clay Henry]

you GP weren't cycling more than likely.
You voltage regulator is fryed and you can get the alternator rebuilt at any starter/alternator shop for around 100.00
A week battery will cause this type of failure so its a good idea to always check your batteries before winter.

[bigbomar4]

You need a new alternator dont bother rebuilding it just get a new one or a reman in the long run it will cheaper.

[Tree Killer]

Well I got a reman from Auto Zone, Lifetime warr. Advance was cheaper but the limted warr. scared me away, they will only replace it once. The new one is charging good 14.28 this morning. C YA