FCIM?

rollingthunder · Jun 1, 2012

Been having a couple issues with the truck. There has been a small knock noise that comes intermittently. The other is a lack of power with low boost numbers-only hitting 25 and the needle stops like it hit a wall(I am running matts SRL+). Last night I had AE on it an noticed the FICM was fluctuating voltage--stayed at 48.5-49v but would dip down to 45-46 every now and then--this was at idle.
I assume this means the FICM is on its way out--would this also cause the knocking noise and low boost\power? I have also been having longer cranking times to start--doesn't matter hot or cold

Mdub707 · Jun 1, 2012

46V is nothing to write home about.

Let the truck sit overnight and test it again with a cold motor. Watch it during key on, engine cranking, and running as well.

rollingthunder · Jun 1, 2012

key on and cranking it is at 48.5-49. Idling it jumps back and forth between 49 and 45. Cruising down the road at 70 it does the same. Only had the truck a month or so, but watching it before it never went below 48--stayed mostly at 49. Now it fluctuates back and forth. Just trying to make sure everything is tight on the truck before I leave for Omaha NE in 2 weeks.

Mdub707 · Jun 1, 2012

Tough call, but 45V is still considered acceptable. It'd be hard justifying pulling it apart to resolder at that voltage. MOST of the FICM's I've seen fail are rarely a just drop dead, usually they'll give you some sort of warning before they go. You'll hear a weak buzz of the injectors when you first turn the key and get codes sometimes for injectors or even the FICM itself. I've seen one die out of the blue, but the truck had been throwing FICM codes for two weeks. Guy just kept clearing it and driving. Out of no where, cruising 65mph down the highway, truck just shut off.

rollingthunder · Jun 1, 2012

Do the injectors buzz at every key cycle?

Mdub707 · Jun 4, 2012

They should, with a newer FICM yes. Some of the older programs buzzed after shutdown from what I have read, though I've never seen one of these.

They should be buzzing every key cycle yes. They will buzz longer when it's cold or the motor is cold. When it's hot it may be a really quick buzz.

rollingthunder · Jun 4, 2012

Sometime mine buzz's at startup-only about half the time though. Today i had 4 starts with several hours between each, and it only buzzed one time. I do know that when I first got the truck it did it all the time (didn't know what it was at the time) and It was longer on cold starts--I thought it was something to do with the gp's. Is that something to be concerned about? Between the voltage flucuating on the FICM and the intermitent buzzes I was thinking something was up with it.

Thanks for all the input so far mdub!

Mdub707 · Jun 5, 2012

It's tough to say. When it doesn't buzz, does it still start ok? If you have access to a scanner you can watch FICM SYNC and see if it's working like it should. The voltages seem good, so you may have something else going on. Another thing that might be worth trying is if you have a buddy with a 6.0, swap FICM's and see what happens.

rollingthunder · Jun 5, 2012

Have AE, I'll check it out when I get home. Just got it so not totally familiar- what am I looking for for values to sync? Haven't payed attention to the buzz vs start time. Sometimes it starts instantly--others there is a couple seconds of crank, and slower, rougher start.