2019 Ford F350 Long cranking\Extended cranking

Joe Diagnostician Texas Posted   Latest   Bounty  
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2019 Ford F-350 Super Duty XL 6.7L (T) 6-spd (6R100) — 1FT8W3BT9KEC81554
Long Crank

Hello. The customer complaint is a long crank duration I have verified the symptom my first step was to remove the pressure control valve on the driver side rail to inspect the valve for rust or any other damage next I collected a fuel sample in a black cup to inspect for metal debris or other contaminents I also performed a water test using blue food coloring. The fuel smells like diesel there are no visible contaminants or metal debris. I have also performed a specific gravity test using a hydrometer the test is in the range of .850-API 35 for my ambient conditions triple-digit heat. I connected a scan tool and graphed actual fuel rail pressure compared to desired during the symptom along with supply pressure according to the scan tool supply pressure is good 372 kpa and actual fuel rail pressure matches desired during the fault. I connected a scope to the fuel rail pressure sensor signal wire and captured the waveform during the symptom. The truck takes 2.5 seconds to start up if I let it sit for 1 minute or overnight I get the same results 2.5 seconds of cranking duration. I performed a low-side fuel pump pressure test using an Fst Pro with a flow meter I get 54 psi and .8 GPM during the symptom and at idle, I also performed the fuel symptom test using the IDS function all tests passed for low-side and high-side. I need technical assistance or another perspective for the battle at hand Thank you.

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Mervin Owner/Technician
Indiana
Mervin
 

Joe I assume there are no codes ? Does the high rail pressure match desired through the fault? If key is cycled a few times before cranking is it the same? Just thinking…Mervin

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Joe Diagnostician
Texas
Joe
 

Thank you for your time I’m sorry for the delay Im battling the clock here pressed for time. I will post some graphed scan data here of the associates pid’s to help you help me. I have performed several suggestions with no change in symptom I am going to test for excessive injector return flow i might also block off injectors while monitoring the fuel rail pressure sensor signal to see if there…

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Eric Owner/Technician
Oklahoma
Eric
 

Joe this may sound silly but have you checked batteries draw and starter draw currents. 2019 with oem batteries in hundred plus heat could be going down.

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Mervin Owner/Technician
Indiana
Mervin
 

Sorry I see you said it matches during the fault …..

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Glenn Owner/Technician
Texas
Glenn
 

Hello Joe, This engine fires (ignites) the fuel by compression pressure, so it does take a little longer than a gas engine, 2.5 seconds is not extensive in my opinion for a diesel. It does require good RPM. As suggested, the batteries could be getting weaker or the starter depending on how frequently this think is cranked every day. What happens if you let the glow plugs operate as they are…

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Richard Mechanic
Illinois
Richard
   

We see this a lot in our shop . We work on a fleet of … f350 6.7 trucks . My next step would be checking for leaking injectors . Excessive return line leaks will cause hard and delayed starts . Also verify VCV valve actual and desired PIDS . How many miles on the truck?

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Albin Diagnostician
Washington
Albin
 

Using a scan tool, monitor the rail pressure and see how fast it builds. Most common rail diesels will not fire until the pressure reaches 5000 PSI.

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Kent Mechanic
South Dakota
Kent
 

Does this truck have a aftermarket tune installed? I have seen some tunes have a longer crank time. If it does have a tune I would put it back to stock and see if the crank time changes.

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Rex Technical Support Specialist
Ohio
Rex
 

Joe, “I also performed a water test using blue food coloring.” What is a water test? I am not familiar with this engine but if it has some type of throttle valve I would make sure it is open when cranking starts. Anything that keeps air out of the cylinders will keep it from firing. If it is not getting air you might be able to pick that up off a voltage signal during crank. Wont take as much…

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Jon Owner/Technician
California
Jon
   

Take the drive belt off and see if it improves start up time. I have had a few with pulleys and a/c compressors failing that put enough drag on the engine to prevent a quick start up and intermittent crank no starts.

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Kyle Mechanic
Illinois
Kyle
 

Joe, What is your cranking RPM and what do your Sync PIDs indicate when cranking?

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Mervin Owner/Technician
Indiana
Mervin
 

Joe There has been several questions and input, you really should give some feedback / answers…. Info…

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