I have a crank and no start condition with P2291.The truck has 177K miles (highway)
The fuel rail pressure sensor shows first 350psi at KOEO then decided to replace it with a NEW sensor and now
shows 0 psi at KOEO. While cranking still shows 0 psi .I put back the old sensor and again shows 350 psi at KOEO and cranking . Looking at the Commanded Fuel Pressure it changes from 4,300psi to 6,000psi.
Any ideas what is happening ?
Yes, the FPL PID changes from LOW to NOT LOW when commanded from the scan tool .
Also,I did a few more tests today :
1.Took a fuel sample of the high pressure fuel rail and I could see on the bottom
of the black spray cap some very,very fine(almost dust ) metal particles
2.Replaced the fuel pressure regulator (FPR) - the old one had a little rust on it
3. While cranking the fuel rail pressure was going from 0 to 115psi and when the cranking stopped
it went back to 0 psi.
4. Pinched the injectors return line - made no difference in the pressure either with KOEO or cranking
5. Unplugged the FPS and the PCM defaulted to 31,200 psi - again no start
The Lift pump is NEW and the engine mounted filter has been replaced.
Is the HPFP gone already or there is some massive leak which prevents even to build up any minimum pressure with KOEO?
Any additional tests I should try ?
Here are the samples. Yes, there are two codes: P2291 and P2539 (Low pressure Fuel system Sensor Circuit) The second one showed up immediately after replacing the High pressure sensor .I don't know why.
That doesn't look like it would cause 0 pressure.
Check supply pressure with a gauge. Should be roughly 80 psi.
If that's good, check for aerated fuel using a clear line
Where should I install the clear line to check for aerated fuel? At the fuel return line at the back of the rail? If that shows positive what would that point to?
Install clear line just after the lpfp, supply side.
You probably won't have the appropriate fittings to make it inline, so just run 1/2" clear line off the spigot from the lpfp and into a Jerry can and watch for foaming.
With the pressure that you're building, little/no metal in fuel, I would suspect a supply issue. That or the vcv is not opening, or pcv is not closing. We'll get to those tho after supply is verified good.
can you test supply pressure off the lpfp? You will need fittings for this. But testing pressure is the first step
Personally, I don't gauge a fuel system issue by rust on components. I've pulled regs that had a lot more rust on them from perfectly working systems.
If you don't have metal in the rails, not likely that the pump has been taken out by rust debris.
I understand but from the pics you can not see clearly the sample. There are very, very fine metal particles . Isn't that enough proof that the high pressure pump is failing or failed already? How big the metal debris need to be in order to conclude the diagnosis?
Shine light in it when you take the pictures. I only see a couple specs. The sample will usually glitter under light.
Make sure the cap you use is thoroughly cleaned as well.
Definitely doesn't look like a blown up pump. Not at all. Usually the screens on the vcv are covered with metal flakes. You don't have any debris that I can see there.
Did you verify your supply yet? Using a clear hose with pressure gauge tee?
What about the contamination of the bottom of the seat of the valve? About the fuel supply - the DFCM is brand new and all filters, I haven't had a chance to measure the pressure but I timed the volume for 30 sec and it is the same as a WORKING F350 . Now, I have an issue with air in the fuel I think because when the lift pump is ON, I can hear some kind of gurgling and on upon touching the fuel line coming from the pump it vibrates/trembles randomly. Is it possible to have a stuck open injector and thats why no pressure can be built?
Whether it's a 6.0, 6.4 or 6.7. if you have low pressure, you verify supply first. Always. Especially when you have a 0 reading.
If you hear gurgling, there is a good chance there's air in the system. Clear line with a pressure gauge. That's what you need to do next
It turned out to be a good mix of DEF and contaminated fuel (mainly water with bacteria and fungus growth).
I am now in the process of replacing all fuel system components.
So far done - fuel tank removed and cleaned, injectors out,fuel lines out (low and high pressure) HPFP out ,and everything else that was on the way
before getting to the them .
Will keep you posted,hopefully with more pictures .
Update:
Everything reinstalled and replaced now I have DTC P0193 and crank no start . Fuel Rail pressure 31,900 psi , Also, the throttle body actuator makes
extra clicking sounds .
What am I missing? Any ideas?
The FRP sensor has been replaced with a brand new - no change. Next is to measure the voltage and connections to the PCM.
Correct - the 31.9K is the max PSI and that also happens if you unplug the connector to the FRP sensor .
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