2018 6.7 extended crank and slow to build rail pressure

[webb06]

Seeking any advice or help with this truck. Truck has 262k miles.

Customer just bought it from another friend who is a car dealer. Previous guy bought it in December and it’s done this since he’s owned it. Extended crank (4-5 seconds) at all times but will always start. Push button start. If you immediately shut it off and restart within 1 second it’ll start as a normal 6.7 does. If you wait 2 seconds (literally) it will long crank and fire up. New owner installed tune and dlete hoping it might fix it. No luck. Truck drives 100% normal and will hold rail pressure under WOT. Low pressure system seems fine. Will build 60psi. Cycle ignition on and off before attempting start is no help. I can watch on IDS and it appears rail pressure is slow to build. Seems to stall around 1500psi then go ahead and build to 5000 and start.

So far I’ve replaced the driver side fuel rail, including pcv and rail pressure sensor. Removed vcv and it’s clean. Swapped anyway no help. Swapped crank position sensor off of my personal truck. Reset crank sensor and all high pressure resets available on IDS. Tomorrow I plan to block of injectors one at a time to see if one is leaking off. If not that then I plan to swap the injection pump.


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[webb06]

Edit: no codes present


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[6.0 Tech]

What’s cam sync and fault do when it happens? I had seen quite a few failed cam sensors on first run trucks back in 11ish


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[webb06]

What’s cam sync and fault do when it happens? I had seen quite a few failed cam sensors on first run trucks back in 11ish


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Sync is yes and cam fault shows no fault


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[sootie]

60psi is low. minimum 80, max 120. What condition is the tank filter in?

 

[webb06]

60psi is low. minimum 80, max 120. What condition is the tank filter in?

Reads same psi as my truck. Do you mean primary filter? Or one literally inside the tank?


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[6.0 Tech]

Does it have factory fuel filters in it? And is the cover for the primary in good shape? Could be sucking air in


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[webb06]

#7 injector was returning too much fuel. Once I blocked off #7 at the fuel rail it started and restarted just fine. Replaced #7 injector and road tested. Restarted as it should.


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[sootie]

Reads same psi as my truck. Do you mean primary filter? Or one literally inside the tank?


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i Meant primary but see you've solved the issues.

 

[6.0 Tech]

#7 injector was returning too much fuel. Once I blocked off #7 at the fuel rail it started and restarted just fine. Replaced #7 injector and road tested. Restarted as it should.


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Good find bud.


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[tom147715]

#7 injector was returning too much fuel. Once I blocked off #7 at the fuel rail it started and restarted just fine. Replaced #7 injector and road tested. Restarted as it should.


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Where do you get the plugs for this test? I’ve got a 19 doing the same thing.

 

[Tiha]

I think if I understand it all correctly, you can start by taking the return line off at the secondary fuel filter on top of the engine. It comes from the injectors. Turn the key/electric pump.
If there is pretty much any return fuel flow then you need to dig deeper to find out which injector or just replace them all.

I need to do it on a spare truck I have. Haven't done it yet. Mine is 2014 with 185k. On video it is just barely longer than my 2016 but it is longer.
I also found the starter was turning slower by taking video and comparing.

https://www.accuratediesel.com/6-7l-powerstroke-injector-return-line-plug.html

https://www.accuratediesel.com/stor...oke-Diesel-Injector-Block-Off-Tool-/-Cap.html