So I'm new here, don't do a considerable of work with 6.0s but do use them in terms of fleet and what not. I've got a 2005 f550 with a 6.0. It will crank, but will never start. Just put a new short block in and bulletproofed it, and had the heads professionally checked, along new HPOP, new injectors and glowplugs all from FoMoCo to aid in the longevity of this fleet truck. All my PIDs are nearly textbook.
If I could find a way to upload IDS DATA to a pdf or something I would. But this will have to do for now


While cranking:
*ICP_PRESS climbs up to about 400ish, enough to start firing, it acts like it wants to start firing but doesnt stay consistent
*Desired of course is around 1160psi
*IPR while cranking up until it reaches 650psi is 85%, Then falls to 30ish.
*Both cam/crank sync and FICMsync are good.
*Relative compression shows spec on all 8 cylinders with the exception of a 2-3% variation, and a mean cranking RPM OF 171.
*Fuel filter housing fills, and maintains around 45psi of pressure if I'm not mistaken, my gauge is broken and Snap-On man is outta town.
*Oil filter removed and drainback pressed down, entire housing fills within 5 seconds.
*Injector buzz tests show good, but if I crank it over for long enough it will trip Cylinders 1-8 injector circuit low codes.

I'm sure that I'm missing something but I tried to start off with as much info as possible. Thanks in advance, and a special thanks if anyone has any info to assist.

 

All 8 injector circuit code sounds like a bad FICM.

What are your FICM MPower, LPower, and VPower voltages when cranking?
Is your IPR new? How about your dummy plugs and standpipes (are they the updated versions)?

You need 500+ ICP to fire

45 psig is pretty borderline. I would want to see over 50 psig, and that is at WOT and full load conditions.

 

IPR is new, I bought the big problem solver/bulletproof kit from Sinister, nearly every seal, o ring, washer and gasket are new in this engine.

I've swapped with a known good FICM and no change it symptoms, codes or PID readings. Both modules, never dropped below 46.5, or around 11.5 respectively unless I'm really straining the batteries during cranking.

I may have found what was causing the issue. I noticed ICP maxed out during cranking at around 380-420ish psi. So I induced air into the system @ the ICP to see if I could hear any leaks, and nothing. Normally, you'd hear air seepage out of the IPR when not grounding it manually. So, I backprobed PCM to ground the IPR both polarities, and no change, even noticed my backprobes were sparking when touching the ground. Which sounds to me like the new IPR was shorted internally. Waiting on the local Ford place to bring me another new IPR and we'll see what happens.

 

46.5V doesn't sound all that good to me (especially if it goes lower when cranking), but if you tried a known good one, then I guess it isn't the FICM.

 

 

I did fix it, the screens was clean as a whistle. But, the new Motorcraft IPR I had put on must've been dropped or something because it was shorted out internally, I could control duty cycle with my Verus, and it would change on the scanner but it actually wasnt moving , put a new one in, fired up like a champ.