Extended cranking, fuel system tests.

Tiha

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I have an extended cranking situation and looking for any insight. Truck always starts. First try every time. But where my 2016 starts on the first revolution this 2014 may take 3-4 revolutions to fire up.
Does matter if it is hot or cold, sits for a minute or a month.
Cycling the key before cranking does not affect it. Full fuel tank or empty.
No codes ever. Truck has been flawless since new. Put a starter on it and thermostat housing otherwise beyond the EGR DEF issues it has never been touched in it's life.
No additives ever. No bad tanks of fuel, never water in fuel.
Filters changed with motorcraft every 10k since new. been changed numerous times since this condition started.
Batteries have been replaced since this started.
It burns clean, no smoke. No apparent power loss. This last trip my mpg was down to 17.3 instead of the usual 18-18.5 but I also see my intercooler hose off the turbo is leaking pretty bad, so I would imagine a big boost leak like that will affect mileage.

Specs, 2014 F250 186k miles. Deleted with minimaxx but stock fueling. Had this truck for over 6 years now, been doing this for at least a year so last 20-30k miles.

Never had a problem so never had to learn, started reading on a recent 3k mile trip and boy did I learn.

While searching extended cranking I kept coming across CP4 failure as cause. This didn't make sense to me as the condition existed so long how is the truck still running and the only symptom I had was longer cranking.

Here I am into it now. Still no codes. Started thinking injector return. Watching the scan tool everything seems fine. Injectors look perfect. Fuel pressure is okay while running and cranking. Actual vs desired fine. Duty cycles fine.

Then I noticed my Key on engine off fuel pressure is 42 psi. I thought the engine light was to come on and code set at 52 psi. so I assumed it was my scan tool. Grabbed a different scan tool. LPFP pressure is still 42 psi.
So I am puzzled by that, is that not the case? Shouldn't I have a check engine light?

Next I have read that the LPFP is internally regulated at like 120psi. Logic says I need to dead head the pump to see if it is working and able to achieve 120 psi. If it can pump is likely fine, if not my fuel pump is likely bad and I should start there.

I think I can take the fuel return line off by the filter on the left valve cover, put a hose on it, maybe pinch it to create back pressure? Will that dead head the lpfp? If pressure does not increase, then I have an external leak, leaky injector (which should hydrolock the engine) Or bad LPFP? At this point I would probably get a mechanical fuel pressure gauge and correct fittings to properly test.

If I understand correctly the CP4 has an regulator in it. Mechanical set to 55psi. Also called an overflow valve. This could be bad, or held open by metal shavings allowing fuel to bypass and not build the 55 psi it is set at.
OR Fuel pressure regulator in the Right Rear fuel rail? (not sure this would do it, will it? I need to research some more on this one) Or maybe you guys know how to test this?

Anyway, I think I have tested about all I can test without tearing the top of the engine down. Is there anything else I need to check while it is still running and drivable?

I would imagine my next steps are to tear the engine down. Check the overflow valve and Fuel pressure regulator, as well as pulling the Fuel Volume Control valve on top of the CP4 and checking for metal shavings.

First picture, Key on Engine off.
Second picture, truck running.
Third picture, Key on Engine off
fourth picture Engine running
Fifth picture Engine running.
 

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Powerstroke Cowboy

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My Dad's 2011 had some of those symptoms. Cranked a little longer and did not get as good as mpg before the CP4 kicked the bucket. He was around 270k I think when that happened.

It did not seem to be as spunky either but that was hard to tell.
 

Tiha

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It is surprising how often you read guys putting in a CP4 and although they found shavings and needed it, it did not fix their problem.

CP4 could very well be where I end up but I hate guessing and in my case I don't see any reason for it unless maybe I have had low fuel pressure for a couple years now. I am puzzled by the lack of low fuel warnings when low side is 42 psi.

Thinking about it, if that has anything to do with my issue and restricting the return increases low pressure above 42psi the truck should start better correct?
So maybe that is one way to troubleshoot it, by restricting the return line?

Reading on the pressure control valve. Says it is open to allow fuel to flow through the rails during Key on Engine off situations, then closes during cranking. But really cannot definitively find what Low pressure PSI should be with Key on Engine off. Don't see anything about the PCV holding any type of minimum pressure, just that it closes during cranking. So that could still be my issue if it is stuck.
Also I think that would be verified by restricting my fuel return line.
 

6.0 Tech

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Verify your primary fuel filter is fully tight. Also seen a bunch where o rings have worn out on some of the quick connects, not enough to leak externally, but enough to suck air. Maybe disconnect them and put some dielectric grease or trans gel on the orings and see if pressure comes up some. Also, the 11-14s were fairly common for the fuel pressure switch to leak, and contaminate the pigtail, kinda like early icp sensors on 6.0s. Verify that is also not a problem. Another thing, since you haven’t owned it it’s whole life, it could be a partially restricted sender from an additive cap or maybe some other shit that may be in the tank.


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Tiha

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Pulled and checked LP rail sensors last night. Dry no leaks.

I pulled the return, Interesting, I am reading the high pressure rail pressure. with Zero system pressure it would bounce from 42 to 0 constantly. So I am now wondering about the pressure sensor and pressure control on the High pressure rail.

Anyway, ran a bunch of fuel out, No air, no metal shavings.

pinched the return line and pressure went from 42 up to 96. That is good enough for me to believe the lpfp is working correctly.

I am going to pull the filters and cut them apart. If I don't find anything I am going to put it back together and run it more.

I took video of it starting with fuel return pinched off. Starts pretty decent. I think it starts better. Also took video of my 16 starting to compare. Start up was very similar, guys at work are laughing at me that I would complain about the difference. LOL But what I was trying to show them was the 14 does not crank as fast as the 16.

Actually starting to question the starter itself. It is 2 years old now. Reman from advance.

I need to video it when it get it all back together without the return pinched off so I can compare. Video doesn't lie, No emotion or feeling in it. Maybe all of this hassle has been a bad starter. Hope so, but at least I will know I am not going to get stranded with a bad CP4 yet.

And really I have the forscan app but I need to get enginuity or Forscan for laptop so I can see more PIDs

We had stopped for fuel in Texas last saturday. It was like 99 degrees, by the time we left the truck probably sat 20 minutes. So everything was heat soaked, starter, fuel system. That startup was the longest crank I have ever had. I thought this was it, this was the time it won't start on the first try, or at all. Wish I had a video of that one.
Hot fuel, weak pump made sense in that scenario, but now looking back, so does a heat soaked starter.
 

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lincolnlocker

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Pulled and checked LP rail sensors last night. Dry no leaks.

I pulled the return, Interesting, I am reading the high pressure rail pressure. with Zero system pressure it would bounce from 42 to 0 constantly. So I am now wondering about the pressure sensor and pressure control on the High pressure rail.

Anyway, ran a bunch of fuel out, No air, no metal shavings.

pinched the return line and pressure went from 42 up to 96. That is good enough for me to believe the lpfp is working correctly.

I am going to pull the filters and cut them apart. If I don't find anything I am going to put it back together and run it more.

I took video of it starting with fuel return pinched off. Starts pretty decent. I think it starts better. Also took video of my 16 starting to compare. Start up was very similar, guys at work are laughing at me that I would complain about the difference. LOL But what I was trying to show them was the 14 does not crank as fast as the 16.

Actually starting to question the starter itself. It is 2 years old now. Reman from advance.

I need to video it when it get it all back together without the return pinched off so I can compare. Video doesn't lie, No emotion or feeling in it. Maybe all of this hassle has been a bad starter. Hope so, but at least I will know I am not going to get stranded with a bad CP4 yet.

And really I have the forscan app but I need to get enginuity or Forscan for laptop so I can see more PIDs

We had stopped for fuel in Texas last saturday. It was like 99 degrees, by the time we left the truck probably sat 20 minutes. So everything was heat soaked, starter, fuel system. That startup was the longest crank I have ever had. I thought this was it, this was the time it won't start on the first try, or at all. Wish I had a video of that one.
Hot fuel, weak pump made sense in that scenario, but now looking back, so does a heat soaked starter.
Id say fuel pressure control valve
 

Tiha

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Id say fuel pressure control valve
I moved the truck a few times this weekend. Now that I try to video every start, starting up cold is pretty decent.

Still leaning towards that PCV or injector return flow. but watching this weekend makes me think it is something that moves, like the PCV being sticky or lazy. I am not a sure an injector would pass too much fuel and then stop.

Need to get a good hot start video too. I took one but where I had my phone you couldn't hear the engine cranking FML. But 3 repeated hot starts, one after the other did take longer to start.
I am hoping to find it cranking slower than my 16 or when cold. Which would make me put a starter in it before moving on to other diagnostics.
 

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