mine tested 48 volts on buzz test then as it was starting but dropped to 26 volts as soon as it started. I checked it more then once to be sure what would cause this. thanks

26 volts
 

I have been told that we need 48 volts at all times . I also have 26 volts after start up ,so I am getting a rebuilt ficm , So far I am lucky I have been able to start and keep my f350 running until I get it fixed .I am also a newbie and just learning my way around ,
try going into ford 2003-2007 and type in f350 in the search bar and you should catch all the threads on the ficm`s and testing with results . hope this helps.

Dying FICM.

Here is a link on how to repair it yourself..http://www.bscustoms.net/diesel/FICM.pdf

Thanks Mdub throwin this into my trucks service manuel!!!:tu:

You are looking for north of 45 volts at any time. The largest load on the FICM is placed on it when the engine is cold, like after sitting 12 hours or longer cold - so test it then, not when warm.

You are looking to test it key on engine off, during the buzz test, during cold engine running, and at 2,000 rpm when the engine remains cold. If EVER you see the voltage drop below 45, you have an issue.

The reason you need to test it cold is that there is a lower amperage draw through the unit when it is warm, thereby less of a load on the module. While FICM's can certainly fail in other ways, failing through inadequate supply side voltage is incredibly common and can result in hard cold starting, poor cold running, loss of power, and a significant reduction in fuel economy.

Ed
Ed@ficmrepair.com
http://www.ficmrepair.com

FICM Test Video
 

Hope it is okay to post this link - I am in no way associated with this company but I know when I first started looking at things under the hood I didn't have a clue.

Mdub if the link posting is a no no just go ahead and delete it - thanks

Technically, probalby not. I doubt the original link I posted is technically ok either.

Just keep in mind when it comes time for repairs, or buying parts, to keep the site sponsors in mind guys! :c:
We're lucky to have FICMrepair as a site sponsor, so be sure to show them your appreciation when the time comes.

I agree with that 100% - it is the sponsors that will keep this site going so we can all learn!:up:

do you have check engine lite on after engine comes to life,easy way to check glow plugs on each bank is to locate the glow plug harness on each side and disconnect ,then take a regular test lite and connect the aligator clip of test lite to the batrey positive post ,then touch ground take note how bright the lamp is,your glow plug harness has 4 pins going to glow plugs take your tip of your test lite and touch each pin at glow plug harness ,each one should lite your lamp bright,if you find one pin that does not lite then you have a open glow plug or a damaged low plug harness,if you replace glow plugs then replace the harness 99% of time you will damage the harness when you pull them off the glow plugs also keep in mind that when you unscrew the glow plug engine oil will leak into cylinder ,you will need to evacuate the oil or you can damage the new glow plug when it gets hot, the oil and the high compression will make the glow plug blister upon start up,,,,, now to test the controller really easy step,,,,,you need a helper to cycle the key on and off,,,,,use the same test lite but now put aligator clip onto the negative post,,the glow plug harness you just unplugged you now will test the other side of it this comes from the controller ,put the tip of your test lite on each pin one at a time while your helper cycles they key off and on at your command,each one should lite the test lite ,if you find one that does not lite then you have a bad controller,,,,,6.0l have a huge problem with glow plugs and controllers ,,,,99% of time it will turn on the check engine lite and store a code ,,,,,testing ficm requires a lab scope and testing ac voltage at each injector,,,,,ficm half shell replacement is, for only 48 volt dc low manpower pids,if ficm is replaced as a complete unit then it will require to be flashed burned by a ford vcm ,i love 6.0l and repair them at my diesel shop ,let me know if info leads you in the right direction