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Discussion Starter #1
Hey guys so I was driving to work this morning and lost all power. One by one, first the radio then my gauges, then the heat then the windows then interior cab lights then my abs light came on followed by my airbag light. It started shifting very strangely and the OD light was blinking. i was able to limp it to work and shut it down and when I tried starting it again it was dead, there was a buzzing sound coming from under the dash and the gauges all went to max reading. I'm thinking its the alternator? I just bought the truck and the kid that had it before me put in a brand new 110 amp alternator...which i am guessing is very small and inadequate causing it to fry? what do you guys think? i want to get the thing fixed before it gets dark after work tonight!

Where can I get a bigger alternator?
 

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Sounds like an alt to me. All those things will start happening with low voltage.

You need to charge the batts and test them first (test one at a time while NOT hooked up). They meed to be good before testing the alt.
 

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Discussion Starter #3
The batteries are not in the newest condition and i just bought the truck used. The truck is sitting in the parking lot at work dead with the windows open...I think I might just go buy new batteries at lunch throw them in and drive to the closest autozone to get the alt tested. Thoughts?

The same exact thing happened to my buddies truck and he said it was his batteries? He has a 2003 with stock alternator and 90K miles. My alternator has maybe 1000 miles on it and is less then 1 month old...could it just be the batteries?
 

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That is up to you. I am not in a position to spend 200a bucks on something it might not be but you arnet gonna make me mad if you want to. It is coming into winter so it is probably a safer bet.

As far as if it could be bats, it is highly unlikely that both died at the same time but one could have been junk most of the summer and not really show up till now. Also, if one bat gives up the ghost, it can drain the other bat pretty quickly. BUT, the truck should have been able to run on the alt alone. I suppose if the bat died hard, it might overwork the alt.
 

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Discussion Starter #5
Yeah I plow with the truck in the winter time and i'd rather spend the $200 now and move on knowing I have 2 good batteries.

Thats what happened the truck ran fine the entire way to work even after all the electricals shut off....once i got to work i let it idle for a minute of so to cool down a little and shut her down....she wouldn't start back up....which makes me think the alternator is good and the batteries are junk? If the alternator was junk wouldn't the truck just shut off because the batteries would be dead from no charge and the alternator wouldn't be supplying any power??? thoughts????
 

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Yeah, you got it. I missed a little bit of the first post about shutting it down at work. Was thinking it shut off on you. Yeah, I would replace the bats but still have the charging system looked at but it does sound like the alt was working.
 

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Discussion Starter #7
i'm new to this mechanical injection system...so i'm not sure how or what needs power. Yeah she ran fine, no sputters hiccups or anything in the motor itself let it idle, idled fine no issues shut it down then no start....so you guys think if I get new batts and take it to get the alternator tested i'd be ok?
 

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Mechanical oil but electronically activated. The pcm will shut down under a certain voltage and (guessing) the other computers onboard will shut down first in an effort to give the pcm the most avalible voltage. I think you should be fine to replace the bats and then drive to get the alt checked out. If you have a voltage meter handy, you can just check the charging voltage while running. It should be between 13.5-14.5V. I check with the headlights on to introduce a load to the system.
 

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i'm new to this mechanical injection system...so i'm not sure how or what needs power. Yeah she ran fine, no sputters hiccups or anything in the motor itself let it idle, idled fine no issues shut it down then no start....so you guys think if I get new batts and take it to get the alternator tested i'd be ok?
Theres nothing "mechanical injection" about a 7.3


Your alternator is fried. When your driving and lights start randomly going on/off and the gauges start getting goofy, thats your ECU losing power and trying to kill off the most unimportant accessories to preserve ECU power. then when power is so low, the ecu starts freaking out and getting stupid because it doesnt have the power to run. If you get it started again, stick a probe to the alternator output. Wait 2-5mins before getting a reading for the GP's to shut off. Then test the idle volts and the volts while @ different rpm's.

Your batteries are fine, your alternator is fried.
 

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Discussion Starter #11
funny story...just went outside and all power is restored...truck fires up like normal no issues....WTF...could it be a short or something? i'm curious if this will happen again...i'm deff going to go get everything tested after work today...
 

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Then your alt. power wire is weak/corroded/not secured, the alt ground is weak/corroded/not secured, or the battery ground/power is weak/corroded/not secured.
 

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Discussion Starter #13
going to try and track it down tonight after work! Thanks for the help guys! I will keep you posted on what I find!
 

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Sounds good. And if everything is snug, stick the voltmeter in the end of the power wire coming from alt, and wiggle/mess with the power line and see if its corroded on in the inside where connection is sketchy.
 

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Discussion Starter #15
Ended up doing the same thing to me on the way back home last night....had a buddy come give me a jump with his duramax and I noticed the clip on top of the alt for the voltage regulator was loose, i snapped it back in and waited for him, we jumped it and all is well now. drove it home let it idle....all good

i'm happy it was something so small...but now I need to listen to the duramax vs ford jokes for the next week!
 

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Good deal man.
 
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