Ok I have been noticing that my morning (any "cold" engine start) performance is getting worse. Now mind you I live in Florida so it is never really cold. I already run 5W-40 oil so its as thin as it can get. I have noticed that what appears to be stiction is a problem, since the engine bucks and wont accelerate very well until I hit about 140 on the temp gauge. It starts fine, no smoke at all. and idles smooth, just wont pull itself away until warmed up. Fuel filters are one day old (International OEM), but the old ones were clean as a whistle. This has been getting worse so dont think its fuel. So today I hooked up my AE software and drove with it connected. I noticed that the FICM main voltage is 45v at start then goes to 47v as it drives. When warm it fluctuates from 45.5-47.5v. Battery voltage at starting is 12.4 and is remaining steady at 13.5 - 13.7 running so I know the batteries are good. My question is what is normal voltage fluctuation for the FICM. Also I wanted to run the injector buzz test but wasnt sure if you can run it when the engine is hot. I ran the test and it said completed successfully, but I never heard even a single sound. Should I have heard them buzz when hot too? Hoping for some advice.

Thanks for any guidance you can give. I am new to 6.0's so pardon if I seem a little inexperienced.

 

My FICM voltage at cold start bounces back and forth from 48 to 48.5 with a steady rhythm. Once ECT gets to about 160 it's steady at 48. I'm not saying anything else is bad but that's how mine acts. From what I've read 45v is minimum reading to call it good.
I'm in South Alabama so not too cold here. Most mornings I crank my truck and walk away and collect my stuff. By the time I get back ECT is 110ish after 3-4 min. I have a pretty steep hill to climb 150 yards from my driveway, if I crank and go with only a minute or so of warm up it takes much more throttle to get up that hill and truck stays in first gear. With the warm up it takes much less throttle and truck will shift. Guess I'm saying each of these trucks are a little different but it's not unusual for it to run much better with a little heat in it.

 

Voltage readings will lead you down the right path probably 95% of the time. They are not perfect. You can have good readings and still have a bad ficm. Do you have any codes?

 

I didnt have any codes and no CEL, just getting tired of the sluggish performance when cold and want to correct it. I would never leave the drive until it makes 120-140 I would be afraid to try to get pulled out in the traffic. Besides, I dont like "pushing" the engine when I know its not ready to go.

 

Your FICM voltage seems marginal, but I don't believe that is causing your low power problem.

I would test my fuel pressure.

 

I have a fuel pressure gauge installed, it has the BB mod and it runs 68 psi and only falls to 62 at WOT. I am thinking it might just be severe stiction? at this point it just makes me crazy because when warm it is just perfect.

 

As your FICM voltage is right AT 45 at key on, I think I'd pull it and do the solder re-flow job and see what happens. I'd also undo the BB thing in the regulater and install the blue spring. You may find that takes care of your problem. At least, I'd do the re-flow solder job. That's a free remedy.

 

You could try disconnecting both batteries, and turning on the headlights for 5 minutes, then connect back up. Don't ask me why, but it has been known to work. Most importantly, it is free.

 

Updated readings. Last night when I left to go home (vehicle sitting 10 hrs) I booted up the AE and watched as I started the truck. When in KOEO it went and stayed at 47.5v, however when I started it, it slowly worked its way down as low as 40.5v gradually working its way back up as the engine temp climbed. Around 120 it was at 45v and by 165 it was 47v. Why would it drop so low then climb back up? I would think that solder problems would be the same across all conditions. If not then should I send this out or try the resolder first? Is there any possibility it is not just the solder connections.

Thanks

 

I would send it out if I were you. I just got mine back from Ed at FICMRepair.com and am very happy with the results. $225 for the repair and testing, return shipping, and a 1 year warranty. Seems like a good deal to me! Get it fixed before it hurts your injectors.

 

If you have one or more intermittent solder joints then vibration can cause an electronic component to make and break contact with the printed circuit board. Even though you are in Florida it may still be possible that as the truck and the FICM warm up the component(s) and/or printed circuit board expand slightly making a previously bad connection good again (although not as good as if it were properly soldered). I have been an electronics technician for over 30 years and it is amazing what sort of problems bad solder joints can cause. I have looked at joints under a microscope that looked fine until you slightly flexed the printed circuit board. I realize we need to keep lead out of our ground water and stuff like that but this no lead solder sucks.

 

AMEN to that (engineer who has had to deal with RoHS compliance here...)

 

I believe this is caused by the high current load of inductive injector heating. When your oil temp is cold, the FICM applies high current to each injector close operator coil. This is intended to warm the injector and avoid stiction. As the oil temp increases, the FICM reduces the current gradually, until at around 130-140°F the engine is warm enough and inductive heating is turned off. Your FICM is weak and cannot maintain 48V during the high current period. The temps and the current involved differ depending on what flash strategy you happen to have.

You can try resoldering, but my advice if you want to fix it right, is to send that FICM to the experts at www.ficmrepair.com.

I'm not so sure it will fix your low power when cold issue, but given the voltages you have it definitely needs a FICM repair. Might as well start there.

 

Sorry to hi-jack this, but concerning the FICM what is the benefit to increasing the voltage to 58? I have read that somewhere and wondered if they where rebuilding them that way or just repairing them to put out the 48v. Is their any harm with them putting out 58v?