Wow. I never cease to be amazed. You guys are incredible. Thanks, Bill.

Let me know if we can help you, JJ - just drop a note over to me at ed@ficmrepair.com.



Ed

 

I am not an EE so I have to think alot harder about these conversations than most. Could some one help me understand what it is about having low battery voltage that damages the FICM? Only having a rudamentary understanding of electricity I would think it would be the opposite. More voltage driving more current through something that can't handle it.

 

The FICM has to ramp up the voltage from the standing voltage to around 48 volts. It's a lot easier for the FICM to accomplish that if the charging voltage is 14+ versus low 13s or worse with dead batteries showing low 12 upper 11.

Josh

 

Isn't the equation Is=Ip(Vp/Vs)? If you decrease Vp doesn't Is go down as well. So if you are reducing the current how does it get damaged? What am I missing?

 

You don't think it's more difficult to convert 11 volts into 48 than it is to convert 14 volts into 48?


It isn't just one equation to figure a DC to DC boost convertor:


VIN × tON = tOFF × VL

And because:
VOUT = VIN + VL

We can then establish the relationship:
VOUT = VIN × (1 + tON/tOFF)

Using the relationship for duty cycle (D):
tON/(tON + tOFF) = D

Then for the boost circuit:
VOUT = VIN/(1-D)

Similar derivations can be made for the buck circuit:
VOUT = VIN × D

And for the inverter circuit (flyback):
VOUT = VIN × D/(1-D)





Josh

 

Ok so I tested as per the procedure 48v on the screw closest to drivers side on koeo buzz test and cranking but 0.00 v on the the far left screw in any of the tests is this normal or am I looking for a wiring problem

 

Superfortress, Bullitt390 you both over complicate the matter. Since both the 48V power converter and the injection driver currents are actively regulated it boils down to simply Power(in) = desired Power(out) + internal circuit losses (inefficiencies), basic conservation of energy law.

At around 9.5V battery volts the power converter can no longer provide 48V out since it is actively current(I) limited to about a max of around 42 amps input. At higher battery voltage (14V) it takes less current(I) to get the same power out, so less of a current(I) strain on the parts/circuit board. Then you have the havoc that temperature (low and high) along with the high voltage transients (load dumps) play on the components.

 

2006 F350 FICM issues!

My truck was running really rough (skipping) and had trouble starting when cold. Took it to our local diesel shop and the FICM at idle voltage was 27 volts. FICM replaced with a 58 volt FICM. This corrected MOST of the issue -- it is amazing how well the truck picks up now when stepping on the pedal. However, at an idle, I'm still getting some skipping (feels like the truck is going to quit). My husband and I will be taking the truck back to the diesel garage, but I want to have some knowledge of what could potentially be happening so that we can understand the mechanic. Any words of wisdom?

Thanks in advance!
Linda

 

This could be many things, Linda, but the easiest thing to start with would be to pull codes. If you don't have a code reader, the ScanGauge II is a solid start for not a whole lot of money. You can read more about it on our site here:

32. You mentioned programming the ScanGauge II. How can I do that?


You can purchase one pre-programmed for your 6.0 here: ScanGauge II.

Note also that there are many on this forum, ourselves included, that aren't at all fans of the 58V modded FICM due to the failure rate on them and the fact that generally provide zero warning of failure. You can read more on what we say about that here: 4. Do you provide a 58 voltage or other voltage modification?

Hope this helps!

 

Sounds like your dealer fixed the major problem by replacing the FICM so the the voltage is better then 48V but note that even raising the voltage will not be a fix for injection "striction" problems which need to be address with serious injector cleaners or removal for dis-assembly and cleaning. Or there could be other common injection system issues. One other common defect is with the fuel injection pressure sensor where the engine can run great a speed but the idle is unsteady, it will idle at normal speed but then intermittently drop by several hundred RPM, almost dying but then suddenly jump back to normal for a while until the next drop in RPM which just repeats over and over again.

From what I see in your info you are in FL, I'm not sure what you call a "cold start" for you folks but where I live a cold start is -20 F. I let my 6.0L soak at -10F for several days and its started fine without a block heat. Noisy though even with 5-40W syn oil in it. Should not need block heater at +20F or above (unless you have some bad glow plugs) but I use timed block heat for +20 F and below because the engine sounds sooo much happier on cold start ; 168K mi on the clock now.

 

This is exactly what it sounds like. We will be taking the truck back today. Ugh!

P.S. - Yeah, no "cold" starts here in Central FL. When I say "cold," I mean after sitting all night in 80+ degree temps... the only thing missing is the sun ;-)

Thank you!

 

Also.... I accidentally double posted this. Couldn't figure out how to delete my post on this thread. If anyone has any further suggestions, please let me know here: https://www.ford-trucks.com/forums/1...l#post15476766

 

Thanks to everyone that has contributed to this thread and the other FICM threads as it has certainly helped me get my truck on the road again. I had some major issues with my truck this week and thought I should share my odd adventure here.

It all began before a road trip, when I decided to change oil and fuel filters before driving 1000 miles away. I've done these tasks before several times without issue and everything seems to have went well until I got on the road and my truck wouldn't get out of its own way. Erratic missing, not enough smoke to note.

Surely I botched the fuel filters and now I have air in the fuel right? I popped them back out and applied some light grease to the o-rings in place of oil just to ensure a good seal. I put the truck back on the road and after a little sputtering everything cleared up and it was good as new....... or was it?

The following day I set out on my 1000 mile road trip, expecting all to be well. Unfortunately that wasn't the case as there was a good bit of sputtering as soon as I hit the road. Once again, not any real smoke to note and I am really believing that I have air in a fuel line. It cleared up after a couple of miles and I had to get down the road so I monitored along the way. 1000 miles and 2 tanks of fuel later I made it to my destination but babied the truck the whole way as power seemed down especially at 80+.

At this point I hit the Googles, suspecting I caused the issue and that I probably have low fuel pressure. Everything says the air should be eliminated with KOEO cycles and it always has been in the past for me. I determined that the OEM filters I purchased from Amazon were not actually Motocraft filters and to eliminate that possibility I picked up a Motocraft set and swapped them in the hotel parking lot.

Now I am thinking everything should be back to the way it was before I performed any maintenance, however I had another think coming. After several KOEO cycles I found myself in a no start situation. The truck would turn over and start to fire (exactly like a normal start) but as soon as it fired it would shut down. If I held it for a long crank, I would get occasional fires but mostly just wear on my starter.

Finally I started looking into other troubleshooting steps as I was sure my fuel system must be fine. The fuel pump was running normally for 30 seconds with key on and a long crank would get me an indication of oil pressure on the dash. Against other recommendations I gave her a shot of starting fluid and it fired up, however it still ran poorly. I creeped around the parking lot and found it missing at anything above idle and no smoke to note. As it warmed up it improved and finally cleared up so once again I thought it may be fixed. I performed a restart or two and then came back a couple hours later to check that it still started and it did.

The next morning of course it wouldn't start and since I had read some threads suggesting the FICM could be bad I finally got a meter on it. Sure enough, 48v with KOEO (after several seconds of delay) and a drop to 25v during crank. Finally I feel like I found the issue and immediately remove the FICM to perform the fix.

Lucky for me we have a nice soldering station at work and the FICM repair went without issue. I returned to test out the repaired unit and found only 11v FICM output with KOEO so at this point I am ready to give up and get a FICM. I double check my connections and everything seems fine, but when switching KOEO I realize that I am no longer getting a buzz test.

I suspect I may have blown a fuse or something for the FICM so I start looking around and find no blown fuses in either panel. After removing and installing several fuses and relays (including the FICM relay) I try the key again and I hear a buzz check! I put a meter on the FICM and find 48v! I crank it over and it fires right up!

Today it's running great, and I'm ordering a FICM relay as a preventive measure. From what I have read the contacts of that relay can become quite pitted, so perhaps that was my issue all along. Being on the road meant I didn't have access to most of my shop tools for better troubleshooting and I may never know the exact cause or if it was multiple issues rolled together but I am glad I found all the info I needed here on the forum!

I apologize for the long story, but wanted to express to others that your problem may not always be related to the last thing you worked on and that it's a good idea to read through the tech folder anytime you have an issue just to refresh your memory on how everything works!

 

Thank you for the post! The more information added to this form, the better!

What is the part number of the FICM relay that you ordered? It may not be a bad idea to keep one as a spare or replace it every 100,000 miles for preventative maintenance.

Thanks again!

 

F8OZ-14N089-AA

Just replaced mine a few days ago. The old one looked ok after I took it apart, but it was a PM measure for me. Tossed the old one in the glove box as a spare.