Had to put on charger this morning to get the 6.0 to fire up. Drove 100 miles with two stops no problem . Sat in campground for three hours, cranks but no fire over. ICP reads good on cranking, FMP 48.5, FML drops to 10 while cranking, VLT drops to 9.7 while cranking. Batts are less than 1 year, ALT is about 5 mos. disconnected neg on battery and voltmeter reads 12.38. Any ideas?

 

Volts should not be dropping that low whilst cranking. Have you load tested either one?

 

Haven't as yet

 

Can you do a voltage test for each cell? You could find one cell below 1 1/2 volts which will drag the whole battery down.

 

You don't get that type of battery with the cell jumper exposed anymore.
The best bet is to use a hydrometer and check each cell and that can give
you an idea on how much might be left in each. But you can bet one or both
batteries are DOA and will need a full charge to see if they will even hold a
charge. That gets into the ALT being bad also. Short trips will not let a depleted
battery charge back up and the last thing is it will take your FICM out.

Time to clean all the cables on both ends both the positive and negative. Next
start with ground points in the engine bay.

Then take a DMM set on DC volts in the low voltage range and do a voltage drop test.

Here is a good Youtube how to.



Sean

6.0L Tech Folder

 

What Sean says here is SPOT ON.

Please load test your batteries and ensure that they are okay. Also take the opportunity to double check your grounds.

While we work on FICM's and could take care of you in that regard, we'd rather have you avoid having trouble!

 

Found problem. My diesel mechanic talked me through several steps over the phone. Shook the wires on the cam sensor and she fired right up. Seems the cam sensor & crank weren't in synch.

 

I clip the leads of my voltage tester to nails and dip the nails into the acid of each cell.
Start with the battery post and first cell. should read 1 1/2 volts or more. Then the first cell and second cell together. will work if you don't have a hydrometer and it is accurate.

 

Awesome! If you decide to replace the sensors, they run $30.15 apiece on our site:

FORD OEM 6.0L V8 CamShaft Position Sensor 8C3Z-12K073-A

FORD OEM 6.0L V8 Crankshaft Position Sensor 3C3Z-6C315-AA

 

That is not reading cell voltage. That is just the reactivity of the electrolyte.
You can get better info and less chance of contamination with iron or zinc
from a nail. Your better off with a hydrometer.

And no I am not yelling at you just pointing things out.

Sean

6.0L Tech Folder