Not FICM but what else?

[06f350sc]

Ok guys, I have been on the phone with couple of 6.0 specialty shops and no one can seem to give me an answer. So here is my situation. My truck is running just like it did when my FICM went out last October. I have checked the Voltage on the FICM by the test method. results are as follows

Key on Engine off : buzz cycle only 42V lowest
KOEO: after buzz cycle 57V lowest
Cranking 56V lowest
Running 57V constant

Several issues. It is dipping low during buzz cycle so I sent it back to Swamps to be checked since under warranty. They said it tested good on bench test and on test truck.

It runs so so on a cold start 50*F mornings and hasnt been much cooler here yet. The other issues is my SCT livewire TS only shows 39V during cranking and NEVER shows above 46-47V ever.

I have also had batteries tested and they are good according to parts house.
Had alternator tested and it is good too... according to parts house
Have had dead batteries 3 times in last month but not sure why if everything in charging system is good.

Also checked for a current draw and is it about .06A which i think is good or is it?

Do I have another issue that makes the FICM show incorrect voltage on my truck alone? both direct Multimeter test and SCT Livewire TS? Any help would be great.

Sorry for the lengthy post but figured I would tell you as much as I could to help.

[mhatlen]

Well, I dont have a 58 volt ficm but I dont see why you should have different voltage during buzz. Have you watched the ficm power and logic power at the same time, also how about at different speeds and operating temps.
If I had to take a shot I would say your ficm has a issue, and the fact you have been down on batteries it may have raised problems with ficm.

Do you have a way to check volts and amps for your charging system.

[Tuscany]

First of all the first red flag is your KOEO voltage of 42v. Take your batteries out and put them on a trickle charge then have them load tested. If one or both turn out to be bad replace them both with new batteries (make sure both new batteries are the same batteries don't mix and match) If they are good than try your voltage readings again and see what it reads. If your voltage is 42v than your FICM is failing again and needs replaced or repaired.

[06f350sc]

Originally Posted by mhatlen

Well, I dont have a 58 volt ficm but I dont see why you should have different voltage during buzz. Have you watched the ficm power and logic power at the same time, also how about at different speeds and operating temps.
If I had to take a shot I would say your ficm has a issue, and the fact you have been down on batteries it may have raised problems with ficm.

Do you have a way to check volts and amps for your charging system.

I have not checked FICM power or logic power at same time... My SCT Livewire will read them just gotta set it to watch. I am not sure what it is as I just got my FICM back from Swamps diesel 2 days ago from being checked. They said it is in good condition and has no issues. But they could not tell me what is causing the issue. other than its the Truck and not the FICM.

[06f350sc]

Originally Posted by Tuscany

First of all the first red flag is your KOEO voltage of 42v. Take your batteries out and put them on a trickle charge then have them load tested. If one or both turn out to be bad replace them both with new batteries (make sure both new batteries are the same batteries don't mix and match) If they are good than try your voltage readings again and see what it reads. If your voltage is 42v than your FICM is failing again and needs replaced or repaired.

That is what I thought. My FICM is under warranty with Swamps Diesel. Sent it back to them to be checked/repaired. They tested on test bench and on test truck and said there was NO issues or low voltage. I also just had the batteries tested before I sent in FICM for repair. Both were good as expected (8 months old) and also had alternator tested and it was putting out 138A during test..

I am completely dumbfounded at this point and can normally fix about anything or figure it out.. This one has got me and Swamps and 2 local 6.0 dedicated shops at a point of no answer...

[mhatlen]

Ok what is your voltages @
koeo
cranking
after start
2 minutes after start once alt is on

There is no chafing on ficm harness/exessive grease /plugs to injectors ok??

Again voltages for your ficm @

KOEO
cranking
idle
high idle
2000 rpm,s

Again after at operating temps

idle
high idle
2000 rpm,s

FICM grounded ?

[Tuscany]

I'm still saying failing ficm or bad batteries. The info you posted indicates one of those two things being bad.

[dannyboy950]

The OP states that he has already had the ficm checked by swamps.

My question would be is he still showing the 42vlts after they tested the ficm and he reinstalled? In that case he may have a chafed wire drawing off some of the voltage being delivered from the ficm.

[06f350sc]

Originally Posted by dannyboy950

The OP states that he has already had the ficm checked by swamps.

My question would be is he still showing the 42vlts after they tested the ficm and he reinstalled? In that case he may have a chafed wire drawing off some of the voltage being delivered from the ficm.

It only shows 42V during buzz cycle. After that is shows 57-58V Cold, hot or anything... It runs better warmed up..

ALso someone alsk about logic and power.. Both are according to my SCT Livewire 11.5-12V cold crank but havent read them driving it around. That is reading right after cranking...

Also my SCT is showing low FICM voltage even though the direct test method is showing it at or above 48V. When direct test shows 57V the SCT shows 42-44V at best until running andd gets up to 46-47 but never higher...

[06f350sc]

Originally Posted by dannyboy950

The OP states that he has already had the ficm checked by swamps.

My question would be is he still showing the 42vlts after they tested the ficm and he reinstalled? In that case he may have a chafed wire drawing off some of the voltage being delivered from the ficm.

And yes it shows 42V after swamps checked it.. They didnt change anything. Same readings before as after... No change what so ever at all. If they say its good then either they are wrong or there is an issue in the truck?

Battereies tested by another test method and they state both are good. 99% of orginal values.