Ok. I have been having issues for awhile and I think I may have found the root cause, now here is the question. I put my truck on my scanner today and found that my voltage only puts out 12.6 at the most and when I have my heater and headlights on it drops to 11.7. (This is a stupid question and I know the obvious answer my voyage is low but) could this cause my 2003 6.0 to run like absolute crap and make things like my injectors to come up as a contribution code even after I replaced some? What else will this damage?
Both batteries were replaced in June.

 

Weak batteries = bad FICM = poor performing injectors (possibly even ruined injectors)

 

That's what I thought. F#$% Me!! I have been replacing injectors, icp, ipr, map sensor and so on and never thought to check my voltage. Would a oem Ford replacement from ford or other parts stores be fine to get my alternator or what would you suggest?

 

I have two alternators. It's an early 6.0

 

I think you need a New Alternator

doesnt sound like it can keep up

the battery light should be on is it??

I replaced mine with a DC Power alternator and I havent heard of anyone having any issues with DC Power alts either

if you can swing it that what I would get
https://www.dcpowerinc.com/
Its built way better than OEM even a smaller pulley so it can crank the power out at Idel what sounds to be your issue not enough power at idel

With power problems you risk every electrical componet on the truck in therory
But usually low power takes out the all things Mark Mentioned

 

The bat light comes on when I first start the truck then goes off in about a min. Where do I find a dc alt

 

+2 on DCPower alternator - they are not cheap though.

 

here ya go


https://www.dcpowerinc.com/


Click here^^^^^^^^

Great Product Glad I only had a 1 alternator setup

Its well worth it you may never have to worrey about a Alternator problem again

I dont know enough about it to say that you could get away just replacing the primary alt for now or Both is a Must

 

Thanks guys. That DC alt is out of my price range but I will be getting them in the future. I fires there is no way to find out which alt is bad without taking them out?

 

i believe you can load test them on the back and see if thye are putting out 14v which is what they should be.

 

Ok. I'll have to check. Thanks

 

Thing is, both alts have to be bad if you're showing low batt voltage. It seems odd that two alts would fail, unless one failed a long time ago and the other failed recently. Either that or something is preventing those alts from getting power to either the A or I circuits.

Disconnect the small plugs from both of the alts and probe with a DVOM. You should have battery voltage to one wire on each plug, and voltage to the other wire with the key on, after the glow plug cycle completes. If you don't, your problem is somewhere else.

 

Cables, battery post cleaning, alternator post cleaning, check grounds. Suspect tow alts would die, but it could be one has bendead a while. Each alt should get you 14.4+ volts on charge, but you have to wait till glow plugs shut off. They alternate between each so check one, no volts, check the other, one should be puttin out.

 

crazy that low voltage could mess up injectors

 

Don't know about injectors but low voltage can take out the ficm and that will affect the injectors.