I've just noticed that everytime I start my 05, 6.0 it takes 45 seconds to register 13.8V. The truck sits at 12V charging light out for 45 seconds after starting and then jumps up to 13.8V. Is this normal for these trucks? I've never noticed it doing this before but it does it every start up cold or restarts. It's got me worried because I sure don't want to fry my FICM or anything else.

 

When I tuned my 6.4, I saw the same thing. I think that is standard procedure for Ford.

 

It is normal. The PCM waits until the glow plugs are turned off before charging starts. Saves the alternator from a big amp load.

 

Thanks for the help. All the more reason to be sure we have fresh batteries to keep the power up to the FICM during this cycle. Appreciate the input.
Don

 

You FICM voltage shouldn't go below 45V at any point, especially during cranking and the GP cycle. If it stays over 45V, you're fine for now.

 

My 2000 7.3 does the same thing. Its normal.

 

I watched it with my AutoEnginuity and laptop hooked up yesterday and the FICM voltage doesn't drop below 47.5V. Mostly stays at 48V.

 

Thanks guy's. Can't believe I never noticed it before. I've had a voltage gauge for quite some time must have caught me sleeping

 

my 2006 6.0 does the same thing, but it takes 5 minutes or so for the charge light to go off and the voltage to jump up. I have 2 new batteries. also dual alternators. Max voltage I ever see with my Scan Gauge II is 13.4 volts, maybe 13.5. I'm starting to wonder A - why does it take so long to start charging, and B - is one of my alternators not charging? If not, would I have a check engine light? I first noticed the long delay about 4-5 years ago, can't recall it being that long before that. Any thoughts?

 

On a truck with dual alternators the PCM selects which one will charge during the glow plug cycle randomly, to share the load. On trucks with one alternator, it will charge during the glow plug cycle. with my voltmeter it's easy to see that the voltage during the glow plug pre-heat is around 11.5 volts, as soon as the engine starts it jumps to 12.2 or so, then when the glow plugs are turned off the voltage jumps to 14.1 or so. The glow plugs are on for a variable time after the engine starts based on engine temps and so on. The scan gauge volt reading does not show actual voltage, it shows the digital data fed to it by the PCM and always reads low compared to a proper voltmeter.

Brian

 

I live in SoCal and it does it even when 90 degrees outside. Until it starts charging, headlights dim, if my radar detector is on it goes into fault from low voltage, etc. just seems like a very long time 5 minutes for this to go on.