Weird crank no start issue...

1jb35 · Nov 14, 2020

08 6.4, ******d, ARP head studs, H&S mini maxx....here is the issue:

For example: a 12mile trip will result in a crank no start issue with a fuel rail pressure of .3ksi. When it does start the FRP is 4.8 - 5.0 ksi. Shorter trips, 2-3 mi, it will usually start back but not always.

The no start ranges from 15 minutes to 10 hours before it decides to start from my experience. Fuel pump is operating normally and no air in fuel. While driving there is no change in the performance of the truck. Although it does throw 3 codes on a no start but only one at a time and any given day they may differ, P0001, P0090 and P0087.

I have noticed that when the key is turned to the run position I typically hear whatever cycles under the hood and the fuel pump and it starts right up ( i dont know what all cycles when the key is in the run position). I can predict a no start because i only hear the fuel pump with the key in run and sure enough, a no start.

Any suggestions/recommendations would be appreciated. Thanks in advance

TD-5 · Nov 15, 2020

All those codes point to a problem with the Hi Pressure Fuel Pump, Possibly a problem with the harness.

powerstroked08 · Nov 15, 2020

If you hear the pump run but don't hear the vgt actuate. Then there isn't any voltage going to the vcv and pcv on the pump. So they default to full open until they have voltage. So the pump will not build pressure.

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webb06 · Nov 15, 2020

powerstroked08 said:
If you hear the pump run but don't hear the vgt actuate. Then there isn't any voltage going to the vcv and pcv on the pump. So they default to full open until they have voltage. So the pump will not build pressure.

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Good call. Without looking at a wiring diagram I’d think the only connector those all share would be at the pcm. Maybe a short in the engine harness itself.

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1jb35 · Nov 16, 2020

Thanks. I will check this out

1jb35 · Nov 16, 2020

I forgot to mention that as along as the truck is running it is fine. So, if the wiring harness or HPFP is an issue would this cause the truck to stall or quit while driving. As long as you don’t shut the truck off it is fine.

ghohouston · Nov 16, 2020

I wanted to say the injectors are worn, but the no start for 10 hours leads me away from that, and I'd absolutely agree it's either a wiring short or a sensor acting goofy.

webb06 · Nov 16, 2020

1jb35 said:
I forgot to mention that as along as the truck is running it is fine. So, if the wiring harness or HPFP is an issue would this cause the truck to stall or quit while driving. As long as you don’t shut the truck off it is fine.

What’s the longest you’ve ran it? Like hours? So it’s never died on you while driving?

If not, has the cab been off recently? I’ve had issues with the 3 bigger connectors under coolant tank that have to be taken apart when cab comes off. Causes similar issues.

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1jb35 · Nov 17, 2020

Ive ran it for a few hours at a time, some idle if went in a store. Never died, or gave any indication it wanted to while driving. No wrench light on dash ever. Only get codes on mini max.

Yes, cab has been off twice for headstuds and up pipe