I have no idea why. The HPOP is mechanically driven, and if you're waiting for 15 seconds KOEO to crank and during that time it starts at 4000 and drops to 800, I don't know why it would do that. The pump is not being turned so there should be 0 PSI. I have no idea how the SCT reads the ICP, but some monitors you need to enter the formula and sounds like someone may have gotten the formula backwards, or some take inputs in a Hexidecimal looking system and are easy to mess 1 digit up. If you're cranking and getting 4000 on the HPOP, that is higher than the 1100 or 1400 at the highest I've seen mine cranking, so that should be plenty to start it. I can't remember if its 350 to start or 500 to start.

If you're getting good ICP, but its not starting must be something else, the easiest thing to test for is the bubble test in the fuel bowl. Also, 80 PSI seems high, especially for stock injectors, so I may also suspect something wrong with the blue spring install. Saw a video that had a kinked fuel return line with high fuel pressure, but did not know if that led to a no start or not.

 

The 4000 to 800 drop occurs when I turn power on, no cranking involved. I've double checked the reading with an Autoenginuity device- same thing. My guess would be that the 4000 psi reading could cause the injectors to reduce output, thus starving the engine for gas when I try to crank before pressure drops to 800. When I wait the 15 seconds for 800 psi it starts on the first crank and all runs great. Is there some way the truck would hold pressure when off?... then when power is applied the IPR releases?
I had tried another pressure regulator from Advance (short notice) and it didn't change my pressure. It also appeared to be junk, so I tried the blue spring one everyone seems to rave about. The 80psi seems to be consistent with what others are reporting. Min psi is 50, 60/70 normal, so I wasnt alarmed at the 80psi.
Thanks for your help

 

The HPOP system is at zero with the engine off, I would suggest replacing the ICP sensor(again, or look closely at the terminals), the readings should be zero psi and 0.24 volts KOEO.

40psi fuel should have no effect on starting(only WOT). FICM sync on the other hand will.

Those tuners can give bogus readings, Try Torque Pro to confirm the readings.

You need 500psi to fire the injectors, with 1500psi commonly seen when the engine starts up.

Monitor FICM voltage, Sync, HPOP(pressure and voltage), IPR%, oil pressure gauge(jump to halfway), Tach needle ...at cranking

These trucks 'need' about 5 seconds between key on and crank, for the computers to boot up.

 

Did you ever find the cause of this issue. I am having the literal exact same issue started June 2018 and been dealing with it since. Waiting to start 10 seconds until the icp says it loses the pressure

 

Disconnect the ICP sensor and the repeat the starting process to see if you have to wait with the sensor unplugged.

 

Yes I still have to wait. I've been through almost everything I can find and pulled ipr and put new screen because I was bored. I'm using forscan to view everything. Screen was clean. The only thing that's very odd is my icp voltage reads over 4 all the time and my psi reads 870 at idle and moves up and down as normal while driving. Why would voltage stay high but psi show accurately

 

If your ICP volts are over 4 at all times, then you MUST have a code.

Sounds like you have a short in the wiring. When the PCM determines that there is something wrong with the ICP volts, it will assume a value for the ICP pressure - one that it "thinks" is correct. We call this an inferred ICP pressure value.

 

P2289 and once the truck is running, I can clear the code

 

As I stated - look for a wiring short.

The code makes sense.

 

I looked pretty hard over the past 2 years and I'll keep looking. I brought it to a shop 2 months and and they told me the pigtail replacement that I did was poor so they redid it with a new pigtail and they told me to replace the icp after that so I did with one from Ford dealership. running low on funds from all this bs going on in the world so i didn't let them fully diagnose it. 700 just to tell me my fan cluch was bad and fix 2 pigtails. So I also went through 3 different brand icp's and 2 pigtails in 2 years.

 

The PCM sends it 5 volts. The signal return voltage is supposed to be just a little above zero at KOEO. It can't be over that unless there is a short, or if you have a bad PCM (which is rare).

 

I just tested straight into the end of the pigtail from battery ground to pigtail on the bottom pin and it reads the 5v. And I tested 2 pins koeo. So looking at the pigtail hole, the right one and the bottom one and it reads .1-.2 while disconnected

 

What does ForScan read the voltage for the ICP when the plug is disconnected?

 

Forescan reads 0 when disconnected

 

So, the pigtail is connected wrong
about 2:42 in this vid shows the ICP connector pinout
pin 1 - ground
pin 2 - 5 volts
pin 3 - signal

 

My apologies, everything i said in that last post was invalid. I been up all night

 

Did you watch the video?

You have it wired wrong as Hydro stated .........

 

Yup I pulled even off the brand new pigtail that I let a well known diesel replace. Pins 1 and 2 are backwards. I'll fix it and get back to you

 

Swapped 1 and 2 pins. Voltage is .24 as it should be and truck starts up..... all this from changing icp with oreillys one 2 years ago, then still having issue so i changed pigtail myself, then letting a shop "properly" fix it only for them to tell me I need a new icp and then i put a Ford one on and it still have the same issues. You see this is why I joined forums? I'm hard headed but I trusted that shop too much. Thanks guys. Positive and ground were backwards

 

 

Stuff happens sometimes