Yesterday, started the truck (05, 6.0) up after sitting for a couple days to drive it around. It had a really strong cold start. Only cranked for a couple seconds and sounded really healthy, very minimal stiction before smoothing out.

Today, went to start up when cold again, let the glow plugs cycle for 20 seconds or so. Cranked for a longer time, 5 or so seconds, went to turn over and died. Recycled the glow plugs, did the same thing again. For the third time, recycled the glow plugs and it fired up. RPMs were really jumpy between about 500-900, then stalled out. Again, tried to restart, and it finally stayed running. After a few seconds, the RPMs smoothed out and it ran fine. When it finally started up, it had a quick puff of black smoke, then a few puffs of white smoke. I didn't have my gauge running, but frequently check the numbers, FICM has always been 48-49V, ICP has always been good while cranking, all other numbers good, no codes. Startup after that was good, also a cold start a couple hours later. Drove it aggressively after warming up and didn't have any power issues.

In NW Ohio, temps have been in the 30s, so not terribly cold. Fuel filters are less than a month old, Oil is 5w40 Rotella T6, two weeks old, also installed a blue spring at the same time, and two new 850cc Motorcraft batteries last weekend.

Not sure what the issue might be. I just filled up my tank yesterday. This is the only time that's happened. All other times have been without issue, especially since replacing the batteries.

Any thoughts, or ideas are appreciated!

 

What are the FICM volts while cranking when its not wanting to start? Monitor them the next time you go out to start it cold after an overnight cold soak ( don't use the block heater for this test )

 

I'll definitely do that and get back. I've done it before, and they were all good, although, this was before it got cold out.

 

What did you find out?

 

If everything else checks out ok, it sounds like it could just be a case of stiction

 

Ok, sorry for the late reply! My friend drove to work Monday, so I didn't start the truck. Yesterday, went to start up and my obd2 adapter would not connect to torque pro at all. So I ended up cycling the GP 3 times trying to get a connection. Never connected. Went ahead and cranked anyway, which took a couple seconds longer, I assume because it was in the 20s or lower, but it had a good start up with minimal stiction.

Just started it today and was able to connect to the obd2 port. While the GP are running the FICM sits at 48.5 for the main and 11V for the other two. While cranking it dropped down to 48.5V and 10V. After starting, it went up to 48.5V and 14V. Also, a good start today with minimal stiction.