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Reworked my FICM; seems to run great

9K views 6 replies 4 participants last post by  bustedknuckles 
#1 ·
I reworked my FICM over the Holidays. I spent most of the time resoldering difficult joints. It seemed like all the difficult joints were connected to the ground plane. I re-flowed the 4 resistors that were recommended on this forum. I also reflowed something like 50 joints on my logic board.
I also added a 48k resistor as indicated on this forum...this should be giving me about 51 1/4 volts out of the power supply.

I've been dealing this cold start issue since I bought the truck in 2006. When ever the temperature dropped below 10 degrees F I would get white to bluish white smoke out of the tail pipe. This would happen even though I ran Valvoline Premium Blue Extreme 5W40. I tried 16 ounces of Diesel Clean with cetane and anti-gel (white bottle) as well as a quart of 2 stroke oil in 28 gallons of diesel. I still had the smoke issue below 10 degrees F.

My results...the truck seems to run like butter... quieter at idle and even quieter than I remember it at full power. I asked my wife to listen me start it while she's standing 20 feet from the truck...she says it's definitely quieter.

Can someone else tell me their results when they did their own FICM?
Is your truck quieter, like I think mine is?
And, does it seem much, much smoother running overall?
 
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#3 ·
I don't think I would have the patience to do this for a few hundred bucks or especially as a favor. I would recommend doing it yourself though if you have soldering experience, patience and a really hot iron. It takes a lot of heat to flow out some of the joints.

I'm really happy with the way mine turned out; I just hope the cold start issue is eliminated down to minus 10...I really hate getting stranded at work.
 
#6 ·
Quickrthanu,

The link that wastedwagesracing posted in response to your message is the exact information I studied before reworking my FICM. Contained in this thread are pictures and instructions on what to resolder. I'm sorry I didn't re-post these exact pictures, but they are in the thread.
I'll help you understand my opinion on why some of the FICM's are failing.
First, my belief of why a large number of FICM's are failing is because (I believe) the circuit board was designed with a flaw.
The flaw on both the FICM power supply and also the FICM logic board is the lack of thermal isolation on a number of the pads connected to the power and/or ground planes. When you try to solder some of these connections, you'll notice how hard it is to get the solder to flow out correctly. The reason is because the pads have an over abundance of copper area connecting them to the power or ground plane. You can see how the designer was so concerned about insuring adequate current flow that they connected some of these pads to the power or ground plane using multiple vias (connections through the board). These look like holes in the pads, that fill with solder if the pad is heated sufficiently. The problem is they also conduct heat very effectively, which draws the temperature of the solder down, making it difficult to achieve a correct connection.

In the links that show what to solder (on the power board) look for 4 resistors, 2 on the left side of the board and 2 on right. Each pair of resistors will be located right next to each other. They look like this on the board. Look for the pictures in the link... the 4 resistors are circled in red for you.

-||||- -||||-

The joints that need work the most are the ones in the middle. These will be very difficult to get hot enough to get the solder to flow right. I used a 30 Watt soldering iron (a wand type, which I bought at Radio Shack). Even with this large iron it took me about 3 minutes to solder each of the joints. The solder would stick, but would not flow under the resistor, leaving a cold joint.

Once you understand how to solder these 4 resistors on the FICM power board, you will understand what the problem is and what you will need to fix on the logic board. There may be many cold joints on the logic board, you need to learn how to identify them visually. Look for components, where the solder joint does not have a rounded filet of solder. But instead, it looks like the component is resting on the pad, with no solder....also, there will be some brown flux on the pad where solder should be. You need to add heat while adding a small amount of solder at the same time as touching both the component and the pad. If you succeed, some of the solder will disappear in between the component and the pad. If you fail, the solder will ball up on top and never flow out. You can retry over and over, but not until you clean off the solder from the prior attempt.

Good luck....if you need additional help, let me know, I can help describe the process to you better if you need me to.
 
#7 ·
Quickrthanu,

The link that wastedwagesracing posted in response to your message is the exact information I studied before reworking my FICM. Contained in this thread are pictures and instructions on what to resolder. I'm sorry I didn't re-post these exact pictures, but they are in the thread.
I'll help you understand my opinion on why some of the FICM's are failing.
First, my belief of why a large number of FICM's are failing is because (I believe) the circuit board was designed with a flaw.
The flaw on both the FICM power supply and also the FICM logic board is the lack of thermal isolation on a number of the pads connected to the power and/or ground planes. When you try to solder some of these connections, you'll notice how hard it is to get the solder to flow out correctly. The reason is because the pads have an over abundance of copper area connecting them to the power or ground plane. You can see how the designer was so concerned about insuring adequate current flow that they connected some of these pads to the power or ground plane using multiple vias (connections through the board). These look like holes in the pads, that fill with solder if the pad is heated sufficiently. The problem is they also conduct heat very effectively, which draws the temperature of the solder down, making it difficult to achieve a correct connection.

In the links that show what to solder (on the power board) look for 4 resistors, 2 on the left side of the board and 2 on right. Each pair of resistors will be located right next to each other. They look like this on the board. Look for the pictures in the link... the 4 resistors are circled in red for you.

-||||- -||||-

The joints that need work the most are the ones in the middle. These will be very difficult to get hot enough to get the solder to flow right. I used a 30 Watt soldering iron (a wand type, which I bought at Radio Shack). Even with this large iron it took me about 3 minutes to solder each of the joints. The solder would stick, but would not flow under the resistor, leaving a cold joint.

Once you understand how to solder these 4 resistors on the FICM power board, you will understand what the problem is and what you will need to fix on the logic board. There may be many cold joints on the logic board, you need to learn how to identify them visually. Look for components, where the solder joint does not have a rounded filet of solder. But instead, it looks like the component is resting on the pad, with no solder....also, there will be some brown flux on the pad where solder should be. You need to add heat while adding a small amount of solder at the same time as touching both the component and the pad. If you succeed, some of the solder will disappear in between the component and the pad. If you fail, the solder will ball up on top and never flow out. You can retry over and over, but not until you clean off the solder from the prior attempt.

Good luck....if you need additional help, let me know, I can help describe the process to you better if you need me to.
 
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