Stumped by no start

dentexpowerstroke

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Truck started off with a very slight miss at idle on the first day it got cold here. Drove about 40minutes home from work and it ran fine without issues, when I got in the driveway and put it in park it had a bit of a rough idle. That condition continued for several days during the cold weather, ran a bit smoother as the truck warmed up. On the way to work I turned onto a 55mph street, went to accelerate, hit 30mph, truck started to lose power and even at full throttle Rpm slowly decreased until it stalled. Pulled over and the truck had a longer crank but started and ran fine. Chalked these up to oil thickness due to temperature. 2 days later the truck would intermittently have the same symptoms (acceleration would cause power loss, rpm drop to stall out) several times on the way to work. Got it home and began looking at it. Ipr, icp, batt volt, ficm power, ficm sync, cam/crank sync all check good, prior to the truck not starting (even with the issues presenting) truck would build and hold 3200psi icp on acceleration. Truck easily builds oil lpo when cranking and fuel bowl fills up rapidly with key on (haven’t checked actual pressure). Oil condition and level is good, changed oil filter while inspecting the drain back valve. Oil pressure regulator looks goods. While diagnosing the issues the truck started then sputtered and stalled quickly. No truck won’t even start, it doesn’t even sound like it’s attempting to fire any injectors. I’ve pulled and checked the ipr screen due to it having 8 new injectors, new hpo, new standpipes/dummy plugs/oil rails, and oil cooler approximately 3k miles ago. Any more ideas, I’m completely stumped on this one.
 
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ghohouston

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Going to try unplugging all 5 v ref sensors, only leaving basically the ficm and ipr plugged in and see what happens. We're halfway suspecting ficm harness has a short. 3 ficm plugs are fully seated, and Keith stated all the pins looked fine. Last weekend when checking things, the truck would not cycle the injector solenoids at key on, and then at one point, they would. We did swap ficm relay, and still no start. Buzz test revealed very weak sounding solenoid clicks, but passed with no codes. We checked the front cover after the low pressure oil regulator was out and there are no needle bearings present, nothing came out on the magnet, and oil filter housing filled quickly when cranking with filter removed.
 

kylejs30

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04 6.0 227k miles.
Truck started off with a very slight miss at idle on the first day it got cold here. Drove about 40minutes home from work and it ran fine without issues, when I got in the driveway and put it in park it had a bit of a rough idle. That condition continued for several days during the cold weather, ran a bit smoother as the truck warmed up. On the way to work I turned onto a 55mph street, went to accelerate, hit 30mph, truck started to lose power and even at full throttle Rpm slowly decreased until it stalled. Pulled over and the truck had a longer crank but started and ran fine. Chalked these up to oil thickness due to temperature. 2 days later the truck would intermittently have the same symptoms (acceleration would cause power loss, rpm drop to stall out) several times on the way to work. Got it home and began looking at it. Ipr, icp, batt volt, ficm power, ficm sync, cam/crank sync all check good, prior to the truck not starting (even with the issues presenting) truck would build and hold 3200psi icp on acceleration. Truck easily builds oil lpo when cranking and fuel bowl fills up rapidly with key on (haven’t checked actual pressure). Oil condition and level is good, changed oil filter while inspecting the drain back valve. Oil pressure regulator looks goods. While diagnosing the issues the truck started then sputtered and stalled quickly. No truck won’t even start, it doesn’t even sound like it’s attempting to fire any injectors. I’ve pulled and checked the ipr screen due to it having 8 new injectors, new hpo, new standpipes/dummy plugs/oil rails, and oil cooler approximately 3k miles ago. Any more ideas, I’m completely stumped on this one.


what is the cranking hpop pressure?


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ghohouston

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A little over 1,000 psi. Actual matches desired. Ipr duty cycle was around 30 or 35% iirc, which tells me there isn't a leak. Also tried with icp sensor unplugged.
 

ghohouston

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I wish I worked on these trucks more often, and remembered more. I used to work on them daily but haven't in some years. Theoretically, it only takes 500 psi of icp to actuate the injectors (we're getting and maintaining over 1,000 psi while cranking) and if there was a major leak, wouldn't ipr duty cycle be up around 85%?
 

dentexpowerstroke

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Forgot to mention, oil gauge drops to 0 on dash at idle after symptoms would occur but immediately bounce back after taping the throttle or shutting the truck off and restarting.
 

bismic

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Any results on the v-reference sensor test?
What are you using to check for codes?
Do you have a known good FICM to try?
 
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ghohouston

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Using my genesis scanner, that reads live data, can clear codes, etc. Used it on literally hundreds of powerstrokes to diagnose in the last decade.
 

bismic

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Did you include the EBP sensor in the "disconnect testing"?

The accelerator pedal has a v-reference circuit also. Since some v-reference instrumentation can't be disconnected, can you capture the v-reference voltage to a file (ie get more than a snapshot view of the voltage)?
 

dentexpowerstroke

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Have ficm and cam/crank sync. Ebp was also disconnected in testing. I didn’t think about the accelerator pedal, I can try that. I won’t have any scanner data until at least the weekend
 

6_Riders

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Your symptoms lead to a bad hfcm. I'd start with the fuel side and make sure that's OK before moving on.
It also does not hurt to clean the map port and examine the hose for leaks (or just replace it).

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Addicted4

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What is the icp doing while cranking? Ipr duty cycle? Ficm voltage? Battery voltage? Rpm? Cam sync while cranking? Need these answered with a scanner hooked up and report back.
 

dentexpowerstroke

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A little over 1,000 psi. Actual matches desired. Ipr duty cycle was around 30 or 35% iirc, which tells me there isn't a leak. Also tried with icp sensor unplugged.

Already answered. As well as cam/crank and ficm synced. Battery voltage is good, didn’t record rpm due to nothing out of the norm with cranking speed.
 

webb06

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Swap ficm with known good. If that doesn’t help I’d check fuel pressure or for air in fuel. But fuel pressure wouldn’t explain the no injector chatter


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