Archived 04.5 hpcr fuel pressure reads 7799psi; high pressure lines, rail empty - no fuel

[DrDeltic]

Anyone seen this one?
fresh Bosch reman CP3, new in-tank pump supplies 17-18 psi with no fuel flowing (dead-headed pressure)
cranking flows 15psi on supply side to CP3
scan tool pressure reads 77XX-8000 psi from pressure sensor
pressure sensor new Bosch
engine cranks at 177-180 rpm
scanner reads 1.6-1.7 amps FCA current
NO START. NO HINT OF STARTING. NO EXHAUST SMOKE, NO INDICATION OF FUEL COMBUSTION OF ANY KIND
high pressure indicated but wonder about excessive return or erroneous pressure sensor reading
pull injector line # 1 - NO FUEL IN LINE FROM RAIL
pull injector line #2 - NO FUEL IN LINE FROM RAIL
pull rail and all injector lines - ALL LINES AND RAIL EMPTY, NO FUEL; RAIL FEED FROM CP3 EMPTY, NO FUEL
new in-tank pump flows 1/2 gallon through open line in 15-ish seconds, 1/2 quart at CP3 inlet banjo in 5-ish seconds
ANY HELP OR IDEAS APPRECIATED - Thank you!

 

[Wayne M.]

What happens to rail PSI if you unplug it? Key on engine off?

 

[p-Bar]

Unplug the FCA and try it

 

[Wayne M.]

Is the FCA a input or output?

 

[p-Bar]

Output. Fuel control actuator

 

[DrDeltic]

Good question.
KOEO rail pressure reads 0.
Added info:
assembled a mechanical 10,000-psi gage to plug into CP3 out line to rail. Rail and all injector lines still off the engine, also Rail Pressure Sensor, temp sensor on manifold, UN-plugged
cranking after priming with in-tank pump, FCA still plugged in, pressure on mechanical gage headed to 10,000, had to crank about 15-seconds. Shut down before un-regulated pressure killed the gage, FUEL PRESENT, as expected with this kind of response. Re-assembling today to check fuel return by each injector (which was my suspicion originally until I saw no liquid in the system)
also suspected scan tool might be not fully developed or eroneous reading, or wiring or electrical, so called software engineer. No problems reported to them and in-use every day around the country.
thank you for all of you

 

[DrDeltic]

P-Bar
thank you. Good thought.
the latest:
unplugged FCA changed fuel flow enough for truck to fire on 5 - had #1 supplying mechanical gage to read pressure un-tainted by goofy PCM strategy of PID rules, which I still don't know. Wish I had some of this and/or raw data verifiable at sensors and actuators.
pressure came up so fast it spiked my gage (10,000psi gage - thought I could catch it fast enough, nope)
plugged FCA back in and re-connected #1 to injector feed. No Start, no fire.
Thank you

 

[Wayne M.]

So what is going on with this one?
Its unclear what your answer to my question was-
Rail pressure KOEO? Your answer was 0, but was that plugged in or not?
What scanner are you using?

 

[DrDeltic]

WayneM
sorry. You are right, I answered "0"
I unplugged the FCA and answered "0" looking at FCA current, NOT FPS psi. My bad. Sorry, Wayne.
when I did what you said to do, scanner says same 7700-8000 psi range as plugged in, as cranking with no start, and as running momentarily on 5.
the scanner reports no real change no matter what. The shop working on this 200-miles away previously, replaced the FPS with new Bosch, evidently seeing the same as me and suspicious. Can't know what they saw prior to replacement.
AutoEnginuity is the brand. I have another 05 to look at and verify scanner. Not here today. I did call AE's software engineer to check for scanner troubles they may have seen and know about. They think all is well with the tool, in contact with users every day. I use it frequently, just have not on these vehicles for these same conditions. They think their Cummins parameters and investment are decent.
Additionally, did a combined injector return-flow measurement to separate hydraulic from electrical.
Specs I have say combined (all 6 at the same time, return line from rear of head) no more than 160ml/minute on a warm engine at 1200rpm. I can't warm the engine running how it does with FCA unplugged, but got 600ml in 30-seconds. Realize unplugging FCA means un-regulated pressure and results in more bypassed fuel than a functioning system, but of course, don't have any experience here to extrapolate my result.
got a thought?

 

[Wayne M.]

"when I did what you said to do, scanner says same 7700-8000 psi range as plugged in, as cranking with no start, and as running momentarily on 5."

So you have a fixed rail pressure under any circumstance? Even KOEO, plugged/ unplugged? you have to focus on that.

I use autoenginuity too. I find it good. Get the update yet?

 

[DrDeltic]

WayneM
update? No. AE engineer told me nothing would change to help at all as I updated in June. He said they did nothing to Cummins dx for HPCR with this update. I believed him.
"Fixed rail pressure under any circumstance" you ask? evidently not.
since rail pressure as reported by FPS through ECM does not change under any circumstance, but real, measureable fuel pressure as supplied by CP3 to HPCR does as reported by mechanical gage, I have to say something in the electronic sensing or reporting process to dx plug (obd2 plug under dash) is amiss. But I don't know what. ECM? Wiring? FPS? FCA? Something else?
This is why I would like FPS raw data for a designated pressure (since scanner reads 8000psi for example, what is FPS return signal voltage supposed to be at 8000psi? Vref on FPS incoming is 5v, ground is ground, what is signal voltage to ECM at 8000?)
Also would like to know what FCA raw voltage should be commanded to trim fuel for CP3 for start-up and idle. It won't start with FCA plugged into harness. FPS reported pressure to scanner does not change with FCA plugged in, or not.
Since you have AE scanner, and 04.5 HPCR sytem also, do you know what your scanner shows fuel pressure to be, KOEO prior to starting?
What it shows when cranking? Idling? This one shows 7700-8000 in all these conditions. Also, what does yours show for FCA current, KOEO? When cranking? When idling? This shows 1.6-1.7 amps. I think this is supposed to be right, but is it accurately reporting what is truly happening? Voltage to FCA from ECM to control the actuator as raw data would be wonderful to know. The bottom terminal on the FCA is controlling voltage on this one. Top terminal is ground. What is the working voltage on a functioning unit?
I know the diagnostics is there to set codes when anything is "out-of-spec" but this doesn't unless I turn the key on with FPS unplugged.
I'm trying to rule out the ECM by checking raw data, realizing that something is wrong somewhere.
If you have more wisdom for me, I'm all ears.
Thank you!

 

[Wayne M.]

I don't know if I can get out there today, but I'll try to look at some PIDs.
I have seen Ford powerstroke PIDs like these, on trucks sick or not, and they're totally rational.
Hey I'm not the wise ones here. They either haven't seen this or they have their popcorn out.
the AE software update has nothing to do with your issue, I was just asking if you got it and if it's different at all. It came out a few weeks ago.

 

[DrDeltic]

WayneM
popcorn. I like that. Some enjoy the show.
us dummies put on the show, others like to watch. Hope they enjoy the show.
i believe this is a weird one.
AE couldn't tell me if 04.5 should show KOEO Fuel Rail Pressure at these figures as "normal"
i trusted it at first, not knowing any better. Then got suspicious and did the mechanical gage plumbing. Come to find out "real world" pressure nowhere near that reported by the scanner. The "why" has me wondering.
thank you formyour help!

 

[cerberusiam]

The why is probably the 04.5 PIDs, they are wacky with what they report sometimes. Could be a bad ECM, or, you have a short in the harness, or bad wiring back feeding signals to the ECM.

On my 05 the RP is 0 with engine off key on, the AE reported pressure is with a couple hundred psi of the ISSPRO gauge pretty much all the time.