FICM or Alternator?

[southend]

Originally Posted by 04cr450

I would look into that circuit if i were you.. Relay contacts could be welded shut.. But i wouldnt worry i dont think it would effect anything.. What im saying is ford has this in the design for a reason and i havnt quite got a logical answer yet but i will...

Alright bud, i'll be waiting.......lol. TBC........hehehe.

Sent from my phone that somebody didn't help me get.

[Kviper]

Just wen't out to put stock tune beck in and the tuner would not let me do anything saying voltage was to low. This was after the glow plug light was out with the motor not running.
With the motor running and the head light's off FICM voltage stayed above 46, If I turned the light's on at idle the BAT voltage would start droping and the FICM voltage started to drop after a bit as well. After running for a while I wen't for a drive with light's on and BAT voltage was peaking at 13.8 and at idle 13.3, FICM V generally 47-48.
Maybe the FICM is not 100% but I think I have a bettery issue or something else going on as well.

What do you think?

[Jarrod B]

I think your oil is low.








Ok ficm is dying. Get a bpd ficm.

[onebadcoastie]

Originally Posted by southend

Your ficm is taking a dump, and your batts look good. Ficm voltage below 45v is a sign of failure, it will only get worse over time. Your voltage is low in the beginning because the glow plugs can run up to 2 min depending on how cold it is. Your voltage cranking is important, you need to see 10+, the higher the better, and 13.3+ after the glow plugs shut off. Bad batteries kill ficms, bad alternators kill batteries, bad batteries kill alternators, eventually. Check out ficmrepair.com when the time comes. Most will say don't run a ficm with low voltage because the potential for injector damage is high. I agree, not sure that is a proven fact yet.

I agree with everything but the statement in red. The reason why I disagree is an under voltage is rarely ever cause for failure of components (except for FICMs..lol..). The solenoids on the injectors are not going to operate if they don't have the proper voltage so really, how would that destroy them? Over voltages on the other hand are extremely dangerous for components, especially when they only rated for a certain voltage (ie: 58v FICMs on 48v injectors). Low fuel pressure will destroy injectors as the fuel pressure is what helps keep the moving components in those injectors from slamming or excessive contact thus destroying them. The fuel pressure for injectors work similar to an air to liquid accumulator. The nitrogen/air in the accumulator aids as a shock absorber to create a cushion within the system protecting components. The same goes for fuel and fuel injectors. This discussion could last for quite some time, that's just my theory.

I know it's not the best comparison but it works....lol

[04cr450]

good point sir^

[onebadcoastie]

To add to that is this. This is a from a caparison of a 7.3L and a 6.0L injector: In addition, instead of utilizing a spring to close the injector once the solenoid is turned off, the injector has two solenoids. One solenoid shifts a spool valve to one side to allow oil into the top of the injector, then a second solenoid is energized to shift the valve the other direction to close the injector. This allows for a smaller injector that requires lower actuating voltage (48 volts maximum), which results in quieter injector operation and allows enough room for four valves per cylinder.

[04cr450]

^

[onebadcoastie]

Originally Posted by 04cr450

^

Thanks.

Back to the topic!!

[Kviper]

Well looks like the FICM and the alternator are both starting to go.
BAT's load tested good.
My cost on everything will be a little over a grand parts and labor with my discount.
One good thing is the CTS cought everything early!

[Powerstrokinva]

Originally Posted by southend

Lol, did I have this debate with you already. Sorry man, I can't remember.....how do you explain the fact that the voltages don't drop though after the engine is cranked? I try my hardest not to post misinformation.

Sent from my phone that somebody didn't help me get.

The reason the batteries don't immediately start dropping voltage is because of their Amp/hour rating. They are designed to hold a certain voltage under a certain load for a certain amount of time. Depends on the battery. In the case of our trucks the batteries are rated for 78 Amp/hours. multiply that by two for the dual batteries. So with 156 Amp/hours on tap you could run a 10-amp load (just for example)for 15.6 hours before the battery would be discharged to 10-volts. So the 50-60 Amp load of the glow plugs and all other electrical accessories running for a minute will only drop the battery voltage just slightly. You also have some voltage recovery in the batteries after releasing the huge starter load once the engine fires up that will build voltage for a few seconds. I am in no means an electrical engineer so anyone who can correct the few mistakes I'm sure I just typed please chime in. I hope that makes sense.

Also if your generator immediately started charging upon start up I would expect to see battery voltage quickly rise to 13.3-13.5 volts which is what the voltage regulator is set to. That set voltage is dependent on temperature as well.

Now I just did some research in my service information and it appears that it might only be a dual generator setup that delays the generator from charging while the glow plugs are running. Here is an excerp from the "description and operation" section of charging system for a 2006 F-350:

The dual generator system is also monitored and controlled by the PCM. The PCM monitors both the upper and lower generator I circuits to determine the output of both generators and sets possible diagnostic trouble codes (DTCs). The PCM controls the lower generator by turning the lower generator off when the glow plug system is commanded on by the PCM to avoid possible damage (excessive voltage) to the glow plugs. As soon as the glow plug system stops cycling, the PCM powers up the lower generator.

So it appears I have just added to the confusion. Anyone with actual Ford service information know any different?