So last weekend I changed alternator. Purchased 110amp from AutoZone. Everything seemed fine. Today as I started truck it had slow crank. Took to oreillys to get batteries and alt check. Alt was reading good diodes but had 11.48 amperage. Any ideas? Don't wanna play this replacement game of alternators.

 

Take it back to VatoZone, and get a real alternator(DC Power). If not, you will play the replacement game.

 

Gonna have system checked at electrical shop to to make sure nothing else is wrong first.

 

I'm sure you've read the threads in the past. The auto parts store alts typically don't do well in these trucks.

Hope there's nothing else wrong. Pay close attention to the results. Was it really the output current at 11.48 A, or was that the output voltage reading?

 

On the oreillys bat/alt reader i beleive it said voltage voltage regulator output 11:48. But then under that said good diodes

 

is the battery light on???????????????


That was Fast Sorrey man


5 DAYS Fast

 

NEVER buy electronic items like alternators, starters from chain stores, there is a reason they have a lifetime warranty because they are selling you a guaranteed piece of crap. Just my humble opinion

 

the 11.48 is voltage, not amperage....

the alternator is trash.
11.48 volts is below battery discharged to 0%.

here's the numbers for auto batteries:

State of Charge

Lead Acid Gel battery AGM battery
100% 12.70+ 12.85+ 12.80+
75% 12.40 12.65 12.60
50% 12.20 12.35 12.30
25% 12.00 12.00 12.00
0% 11.80 11.80 11.80

running it like that will kill your batteries, ficm, and
injectors, not necessarily in that order.

those three items are about $5,000.
the best dc power alternator is about $500.

it's your money. using a cheeze whiz alternator
will prove to be the most expensive money you
have ever saved.

take it back, get your money back, and call up
either ed@ficmrepair.com or dc power and get an
alternator.

with a good alternator, my idle voltage cold is
14.2 with the glow plugs on. it will charge the
batteries with maximum drain on from the
engine and accessory loads, something an oem
alternator will NOT do.

this engine will suck down your batteries with
a discharge of 60 amps until the glow plugs
turn off. this will kill your batteries on short
trips in winter.

that's my nickels worth.

 

when it says diodes good, it means they aren't blown and
passing AC into the output.

the output voltage of a healthy electrical system should be
above 14 volts.

 

If your batt light will not come on with the key on engine off the alt will not charge.

 

I've noticed mine running idle at night with headlights at 12.5v to 12.9v. Batteries are only a year old. The Batteries never seemed fully charged. I just ordered a new DC Power 190 amp for $350. That's less than ford OEM and it has a better warranty. motorcraft 1 yr and dcpower 2 yr. I don't have any accessories on my XL just pull a trailer. Should be big enough.

Daniel