Originally Posted by Nuggets
I am encouraging the customer to let me diagnose it so I can fix the problem verses whipping multi-thousands of dollars at it and crossing my fingers.
As far as voltage at the injectors, how should I check them? DVOM or is an ocilliscope required?
I keep an eye on mine through a scangauge II. I can check 3 different voltages with that $150 guage. You can also pull the small cover on the FICM under the degas (torx 27?) and check voltages from there.
It probably has the older style ficm which is a 7 pin the newer ones are 4. By pulling the cover you can put a basic volt meter to one of the pins (i'll have to check on the 7) and check voltage during glow plug warmup, starting and running. At no time should the voltage drop below 46v.
From my understanding the ficm converts a 12v system to 48v through 4 different areas in the ficm. On my truck I had an entire area quit working during startup and I was only running 36v during startup (truck ran great the entire time). I pulled the ficm apart and resoldered a few joints and have had it back up to 48v ever since. Just because you are at 48v does not mean that it is working perfectly but it is an indicator.
You may also want to test and see which flash that truck has because they did go to a harsh one to try and save the injectors and ended up burning out a lot of ficm's. I believe the newest is a heat induction something or other.
Like i said, i am no mechanic but i worked through a lot on a couple of 6.0's and they're pretty simple. I have heard horror stories but most seems to be derived from lack of maintenance and preventative maintenance.