Concerning the high pressure system; I can't really see the fuel sample clearly so I don't know what to make of it. The place to look for metal debris is in the bottom of the primary filter cap and the a sample from the left fuel rail when removing the FPR or the FRP sensor... and there ARE non-ferrous metals in the HPOP so a magnet test is not conclusive. The presence of metal alone pretty much is. A 2 or 3 small flecks do not concern me. I reread all of your posts and you did change the VCV and the PCV but you made no mention of looking for debris in the pump and on the VCV screen and the PCV for rust and debris. I am guessing nothing jumped out at you which is good.
Your trip to the dealer and the result is about what I could have expected. To be honest you can't rule out a high pressure system failure - I am just not convinced. Yet. Here is why...
I am going through everything you are telling us and looking at ALL of the codes you have reported which are:
- P0089 - Fuel Pressure Regulator Performance (damaged fuel pressure control valve)
- P0193 - FRP sensor A circuit high
- P06A6 - Sensor reference voltage A Circuit range or performance (VREF out of range)
- P0336 - Crankshaft Sensor A circuit Performance/range
The second, third and fourth codes are related in that they tell us there is an electrical issue with the Reference Voltage A circuit or the sensors connected to it. Combined with the extremely erratic FRP voltage you monitored I am still thinking you have a wiring concern which must be ruled out before condemning the high pressure system. The first code is likely the result of the erratic FRP reading which the PCM uses for control feedback so we will put that on the back burner for now especially since you have replaced all of the related parts.
A little more backgound - the PCM has three VREF legs that it uses for all of the sensors. Your FRP and Crank sensor share the SAME VREF LEG (A) along with the following sensors: Diesel Particulate Pressure Sensor, Accelerator Sensor, EGR Throttle Plate Position Sensor and the A/C Pressure sensor. The PCM monitors circuits and sensors however an intermittent fault can commonly happen too quick to set a code. Additionally, the PCM monitors the Crankshaft position and Fuel Rail Pressure sensors more closely which might explain why you only have those codes. This is important. So I want you to RETEST the VREF and Signal Return circuits in the same manner you did before performing the harness wiggle test going to the other sensors sharing those circuits looking for shorts to power, ground and opens.
I am attaching a General Service Bulletin that explains all of this and lists the codes you are diagnosing. It will show several known locations of for wiring failures and you should also closely check and inspect the harness that runs along the right frame rail leading to the DPF pressure sensor as there have been known cases of crushing and chafing between the underside of the cab and the frame rail as well as the DPF pressure sensor bracket.
I am glad that you seem to be understanding all of this - this is one of the more technical posts I have offered. At this point I have pretty much given you all I have on this and I hope that you do in fact find a harness or sensor fault and don't have to shell out the coin to replace the high pressure system.
I wanted to post my experience with the mechanic yesterday and some more of the anomalies and see if what he is saying makes sense or if you think I need to take it elsewhere to get a second opinion.
This thing is weird! There are so many things that point to it being an electrical issue but I can't seem to find any electrical problems! I looked over all of the wiring starting from the back of the truck along the passenger side rail all the way up to the driver side fuel rail. I did not visually see any issues. I then started the truck and had it running at idle. The mechanic came out with his computer and diagnostic tool with which we monitored Commanded pressure, "actual" pressure, and FRP voltage. I went under the truck and wiggled and jiggled the wiring from the back of the truck all the way up to the driver side rail again. There was no fluctuation in voltage or any issues with the truck at all. It would not "screw up". In fact it ran for about 10 minutes with no issues at all.
At idle it was sitting at ~5,000 psi. I was able to rev the engine with no issues. The psi would go from 5,000 and increase linearly up to whatever I commanded with the throttle (5k-approximately 18k from what I remember). The truck seemed to be running like new. The mechanic then used his computer to increase commanded fuel pressure to approximately 7,000 psi and the actual pressure rose steadily with the increase. He then ran a high pressure test. As soon as he hit start on the high pressure test, the truck died.
From the troubleshooting that I had done on my own, prior to bringing the truck in, if the truck was giving me issues, if I waited a day and started working on after having set for about 12 hours, the truck would act normal for a while and then start acting up again. Sometimes, after changing a part, I would think that I resolved the issue because it would act normally while sitting in park. I would then put the vehicle in drive and start driving around my yard and then all of the sudden it would die. After it died the first time that day, I could start it back up but then as I put it in gear, it would immediately die. If I would wait a day, I would be able to start it and move it back to my garage for more troubleshooting.
The mechanic said that the other day when he was looking at it, at first it was acting normally but then once it started acting up, he could start it and then if he got on the running board and began jumping up and down to shake the truck, the truck would die which led him to believe it was an electrical issue. After troubleshooting all of the wiring though and the fact that when he runs the high pressure test it immediately dies, he thinks that the pump needs to be replaced (along with everything else). There are also stickers on a box in the engine that indicate the injectors were replaced at some point prior to me owning it. He said one other thing he could think might be the issue is that moisture got in the fuel and potentially caused one or more of the injector's piezoelectric sensors to short which might be causing the pressure to spike and or a voltage issue. He said if that is the case though, the pump might be compromised also so he recommends just replacing everything.
I asked him if it could be an issue with the PCM and he said, potentially but more than likely, if it was, I would be getting a code for that. I asked him if it was possible for him to "re-flash" the PCM and set it back to stock and he said he could do that but he was worried that because I have a delete and tune, if he did that, the truck might not start again. I asked him if he reset it and I just reinstalled my tune, wouldn't that work? He said it might but it also might cause issues with updates and other things needed from my Mini Maxx and he didn't want to lock out the truck.
My questions are:
1. If it was the pump failing, why would it act normally some times and others not, especially after sitting overnight?
2. If it was the pump, wouldn't I be getting some type of code associated with low pressure and not high pressure?
3. Why would the pump put out high pressure while in park with me revving the engine but then when put in gear or the high pressure test being run, subsequently die?
4. What are your thoughts on resetting the PCM with a deleted vehicle? Is it worth it as a last ditch effort or might I totally screw things up?
Thank you again for your time ford_doctor! I may just have him do the entire system, I just don't want him to replace everything only to find out that the issue isn't fixed because it was an electrical component.