2014 6.7 CP4 anyone have experience?

[CarterKraft]

Quick Google search, does 60 look more inline?

How to check low pressure fuel pressure

I have a 6.7 with codes P228F (Fuel Pressure Regulator 1 Exceeded Learning Limits - Too Low) and P127A (Aborted KOER - Fuel Pressure Failure). Even though the PPT doesn't ask to check LP fuel pressure the hotline said to check it as that is usually the cause of these codes. This truck has passed ...

www.forddoctorsdts.com

 

[Tiha]

Quick Google search, does 60 look more inline?

Yep the range is like 53-75 psi or something.

I was hoping someone would have something to say about that. Because by spec it is too low.

But here is why I tend to ignore that reading. That reading is taken from the high pressure fuel rail on a sensor calibrated for 30k psi. So to be off a few PSI at the bottom end, seems reasonable right?
I mean that is like .02% tolerance.

Also, the LP switch, which is a different sensor is set to trip at 53 psi. That is the switch that gives the low pressure alarm and puts truck into limp mode.

So if my pressure was really only 42 psi, then the LP switch would have to be bad as well since I never get that low pressure alarm. Make sense so far?

Also, the Low pressure fuel pump is internally regulated at 120 PSI. Clamping off the return line, dead heading the pump, and reading pressure off that same sensor it reads 96 psi.
So assume pump bypasses at 120 psi, but reads 96 psi on scanner. That is 24 psi off.

Now apply that "reading 24psi low" to the 42 psi I get under normal operation. 42+24= 66 PSI, Well within spec.

Sound logic isn't it? I mean I really need to make an adapter and put a manual gauge on it to know for sure. But that sucks. LOL.

 

[Tiha]

I ordered a fuel pressure gauge adapter. Be here next week.

Pretty sure I am okay, But now I gotta know for sure.

 

[CarterKraft]

Yep the range is like 53-75 psi or something.

I was hoping someone would have something to say about that. Because by spec it is too low.

But here is why I tend to ignore that reading. That reading is taken from the high pressure fuel rail on a sensor calibrated for 30k psi. So to be off a few PSI at the bottom end, seems reasonable right?
I mean that is like .02% tolerance.

Also, the LP switch, which is a different sensor is set to trip at 53 psi. That is the switch that gives the low pressure alarm and puts truck into limp mode.

So if my pressure was really only 42 psi, then the LP switch would have to be bad as well since I never get that low pressure alarm. Make sense so far?

Also, the Low pressure fuel pump is internally regulated at 120 PSI. Clamping off the return line, dead heading the pump, and reading pressure off that same sensor it reads 96 psi.
So assume pump bypasses at 120 psi, but reads 96 psi on scanner. That is 24 psi off.

Now apply that "reading 24psi low" to the 42 psi I get under normal operation. 42+24= 66 PSI, Well within spec.

Sound logic isn't it? I mean I really need to make an adapter and put a manual gauge on it to know for sure. But that sucks. LOL.

Yep solid work so far.
I don't like the assumption on the rail pressure, LP deal (sounds like you aren't sold either) so a mechanical gauge comparison would be a thing I would do.

The CR stuff I work on there is no where near enough resolution in the rail pressure sensor sub 100 psi for that to work at all.

 

[Tiha]

To Update,

Pretty sure I need a CP4.

I have a crank, no start situation.

was waiting on fuel pressure tester adapter, it still hasn't showed. But I remember doing my LPFP testing last fall I clamped off the return on a hose that was just hose clamped on.
So I made a tester that just uses hose clamps and installed it in place of the return line, steel rail to Fuel filter.

I have 62 PSI from the Low pressure fuel pump.

truck will not start, will not build rail pressure.

Tried all kinds of bleeding procedure. Nothing. It was running. I shut it off and was waiting for the Fuel pressure tester. Now no start. Simple as that.

Found one guy online that said.
"quick tip here. The typical failure with cp4 pump is a bad valve seat on the Intake non-return valve (suction valves). We have found that when an injector line is cracked open, and the key turned on to operate the lift pump a good cp4 the fuel will ooze out. In the case of failed suction valves the fuel will poor out and travels about 1.5 to 2 inches up."

I have that, I get 3-4" though not just 1.5-2" But I could not find anyone else online saying the same thing. No other way to verify it.

Tried to pull the pressure regulator return line to flow test it. Could not get the fitting off.

tried to pull the pressure regulator on the Left fuel rail. Got it loose, it will not spin out unless I pull the injector hold down, or fuel rail loose. At that point I just threw everything in back of the pickup and pushed it outside. I am out of time.

Yep, Seems like it failed sitting in my garage.

I pulled the intake to inspect the CP4 for metal shavings again. Nothing, still clean. There just isn't much information on failed CP4 pumps that are not full of metal shavings.

Quite the emotional roller coaster. Originally thought I needed the whole decontamination kit. Then thought I might just need an injector or two. Then started thinking maybe I just needed a Low pressure fuel pump.
Then bam I am back to needing a CP4.

Besides the Pressure regulator tests there isn't anything else to test. After thinking about it over the weekend I think I am just at the point of having to buy a CP4.

So now, which CP4 to buy?
I probably won't put 100k on this pickup. No HP changes, no fancy tuning.

There are Remans for $700 that nobody admits to using. New Bosch for around $1000 and it just goes up from there with pumps claiming to be better.

 

[CarterKraft]

Can you get the suction valve by itself? I would think that part is the "Failed" part for your symptoms.

Can you pull the valve and watch/listen to confirm it is moving?

In your boat if I had time I would just pull the CP4 and get it apart and see what is going on with it.

 

[Tiha]

Can you get the suction valve by itself? I would think that part is the "Failed" part for your symptoms.

Can you pull the valve and watch/listen to confirm it is moving?

In your boat if I had time I would just pull the CP4 and get it apart and see what is going on with it.

I actually haven't had time to look.

Found parts breakdowns, but not sure if I can order parts. Had thought about rebuilding it myself. Like why not?

But it may be like many other things, cheaper to buy one than the parts to rebuild it.

Either way I will probably take a look when I get time to pull it out. But honestly when I get that time I think i would want one laying there to throw back in right away.

I had so much stuff to do in May and this truck plugged up the garage all month, waiting parts, or tools or something.

 

[CarterKraft]

Thinking about this more a zero pressure situation is rare in my world.

You are saying it is making zero pressure or just low pressure and definitely not enough to enable injection?

It might be a good time to check bank return rates, it might be possible the leak is substantial enough to not build pressure now. (This is what we see usually when it's a crank no start)
Is there a easy way to check returns all together?

Edit: where you saying you measured delivery flow and it's not coming out of the discharge ports?

When I've had dead pumps it was a stuck suction valve or destroyed. The suction valve is a easy fix.

 

[Tiha]

You are saying it is making zero pressure or just low pressure and definitely not enough to enable injection?


Is there a easy way to check returns all together?

Edit: where you saying you measured delivery flow and it's not coming out of the discharge ports?

When I've had dead pumps it was a stuck suction valve or destroyed. The suction valve is a easy fix.

Zero pressure measured while cranking. Watched on Forscan monitoring the Fuel pressure sensor. My pressure is at 42 PSI, from time to time it would blip to 96 psi while cranking.
But maintains a constant 62 psi on manual gauge.

Probably is a way to check the returns, they all come back to one place. When i get back on it I will look at it more.

I had Zero return fuel return from the injectors, KOEO and Engine idling. I thought that was odd. But if they are good I understand it is supposed to be very little.
Also understand there needs to be 45psi back pressure in the return lines for the injectors to operate properly. Seems odd to have no flow but it somehow achieves 45 psi back pressure?

In edit: While attempting to purge air from the system I removed the last return on the pass side rear injector. Turned key on and pump a bunch of fuel back into the return lines. The 45 psi I would imagine comes from the LPFP pumping, not return from the injectors.

I had unhooked the entire passenger side, plugged the line to the driver's side and ran clear tubing off the injectors into cups in theory to measure them.
but Got no flow.
Did the same on the driver's side. same results. I totally expected to find one injector bypassing a bunch of fuel after finding the CP4 clean.

I haven't looked much yet, but a quick search for rebuild kits only show seals.

 

[Tiha]

Talked to a friend of mine yesterday about my situation, at a dead end pretty much ready to put a pump on it.

He works for a diesel specialty shop. They see the worst of the worst. So his opinion is a little skewed. For example they have a truck in there now that has been towed to 2 other shops and still not running. They also work on all brands so hard to stay focused on what I need help with from time to time during the conversation.

Besides that, I hate when people only ever call me when they need help so I avoided it as long as I could.

Right now I am focused on Crank No start. Not building rail pressure which honestly is probably not related to extended cranking.

He said a few things, but basically with the testing I have already done. Fuel pressure, fuel flow, checking for codes, injector buzz test. I only have two tests before replacing the HPFP.
One is the Pressure control valve on the Left Rail. Need to flow test it. It can cause a crank no start condition.
You take the return hose off the rail, plug it. Run a hose from the rail side into a bucket. KOEO fuel should dump out pretty fast. Try cranking, Fuel flow should completely stop. We both kind of felt this was not my issue because I see no Blip in rail pressure while cranking. But you don't know until you know.
IF the fuel does not stop completely replace Pressure control valve.
If the fuel does stop move to the volume control valve in the top of the cp4 pump.

KOEO the VCV should buzz or vibrate, or rattle. Anyway you should know it is on.
If it does not do Electrical pin point test.
If it does Buzz pull valve. (it actually says replace at this point but we are going a step further) Pull the plunger out of the valve, see if it moves freely.
If plunger is stuck replace valve.
if plunger is not stuck Replace HPFP.

He dumbed it down very quickly for me. A bad VCV on top of the CP4 makes the most sense for my immediate fail condition that I have. But you don't know until you know. It could still be the CP4. But I feel like I have some confidence going forward with that.

On his own he added that the return flow test I did was worthless. You need to bench test the 6.7 injectors. They need back pressure to operate properly. From his view point they fail all the time. He really thinks I need to pull them and have him bench test them, but he also doesn't think they can create my no start condition. Well, not a no start condition, but no rail pressure condition, They can run perfectly fine, not throw codes and still be bypassing fuel like crazy.

He said the PCV is a common fail item (from his point of view) VCV does fail but not as often.

A situation like mine is not uncommon. Clean VCV inspection but no start. He added that if I would throw a Decontamination kit in it. I would fix every one of those problems that can be creating my condition. Pump, Injectors, sensors and never now the cause but it would be fixed. So he doesn't bash shops that push them. He said a decon kit can be done it about 10-16 hours. Doing pin point testing like I am doing, a shop could easily spend 16 hours doing just that then still end up doing a decon kit.

Not sure what other insightful information I forgot to post but I need to test the VCV and PCV. If it still is not running then I will probably pull the injectors for testing and order a CP4.

 

[Tiha]

Tested the PCV and VCV. Pressure control valve on the left rail and volume control valve in the top of the pump.

Unhooked the return line from the PCV, put a hose on it and ran it into a bucket.

KOEO fuel flows out the hose into bucket.
Crank engine, flow stops. that is exactly what it should do.

Since I was only looking for fuel flow, thought I didn't have any, I didn't unplug the VCV to see if that stopped the flow as well.

I did test the VCV for voltage. I did NOT feel any clicks or vibrations or hear any noise from it like I had read elsewhere.
Also pulled it apart for kicks. The plunger was not stuck. I would not recommend doing this, pretty easy to get a metal shaving in there or dirt.

Crappy video I know, but you get the idea.

In edit: So I need a HPFP. Whether it be a inlet suction valve stuck open or other catastrophic failure. Also going to pull the injectors and have them tested. I expect to have a couple bad ones at least.

 

[Tiha]

Injectors are out, look better than I expected. Off they go for testing this morning.

I suppose the best I can hope for is to have 3-4 bad ones that bypass enough flow to prevent the rail pressure from climbing.

Pulled the PCV, pressure control valve as well because I was there.

Looks clean. Thought it was interesting, the end looks knurled. It isn't metal flake, nothing that will come off. Looks machined, I wonder what the intention was in doing that.

Was thinking about putting a new CCV filter on, but if it was meant to be a maintenance item then why would Ford put the IAQ numbers on there?

I was certainly blessed pulling injectors, maybe took me 2 hours. No broken hold down bolts, all the injectors popped right out. None of the horrors you read about.

 

[Tiha]

Next update.

Injectors tested, 4 failed.

But not in a way to create a no start condition, as in bypassing fuel. They failed IAQ or IAS test, meaning, (I think) that the computer cannot accurately control the injector.

That would cause my cold miss, or low idle, idle surges. Smoke, soot. Run ability problems. Going back to my fuel trims posted earlier. I could about guess which ones it was. Even though they didn't pass the limit, they were certainly and clearly farther off than the others.

So 4 passed, 4 failed. Installing 4 new ones. They are getting me prices on Alliant injectors. I have no idea who makes a good injector for these. Or if there is a difference really. I know anyone can replace parts in an injector but can everyone test them properly when done?
Kind of hate to go through all this to put crappy, marginal injectors in.

Then I need to pick a CP4 and get it ordered.

 

[CarterKraft]

Don't let me mess you up but did you ever figure out if a SCV could be the problem?
IF you have no debris anywhere and no pressure I am really curious what failed?

edit: re-reading your last couple posts, the VCV will be PWM and I'm not sure a test light will get you where you need to go, I measure amperage on those with a amp clamp. You should feel it move... Maybe it wasn't being commanded because of something else?

 

[CarterKraft]

If you are getting a new CP4 anyway maybe buzz testing the suction valve on a battery is worth a shot, just to verify it's operational.

 

[Tiha]

Don't let me mess you up but did you ever figure out if a SCV could be the problem?
IF you have no debris anywhere and no pressure I am really curious what failed?

edit: re-reading your last couple posts, the VCV will be PWM and I'm not sure a test light will get you where you need to go, I measure amperage on those with a amp clamp. You should feel it move... Maybe it wasn't being commanded because of something else?

Right, the VCV or SCV, lol there seems to be a different term depending on who you talk to.

My test was just to see if there was voltage available. That was one of the pinpoint items in the troubleshooting tree. I had read you should hear or feel it buzz, but I could not. Felt dead to me. I could not reach the one on my 2016 to feel it, but I certainly could not hear it for comparison.

But my understanding is that if the VCV is dead, stuck closed I would not have gotten fuel flow during the PCV test. Maybe that isn't correct, I have no idea. Again, not a lot of info on the net about testing VCV/SCV.

Kind of right back to the same old thing. When my friend called about the results of the injector tests and I asked him if they had injectors in stock, he said nope, but they have a decontamination kit in stock for $4k.

A decontamination kit would fix all of my problems. It always would have without ever knowing the cause.

Right now I am looking at what? $300 an injector? so there is $1200, and maybe $1000 for a CP4. so $2200 vs $4k, Am I saving that much?

Thought about throwing a VCV on just to see what happens. They are like $100 on ebay, But I can't do anything before I get the injectors back in. Who knows when I will get to that. Next two weeks at least are booked for me.

Maybe I will shop decontamination kits just for kicks. It is appealing to have all that stuff new. I have two questionable connectors on the my return line. I would need install kits for the 4 injectors I reuse. If I had 4 injectors fail can the other 4 really be all that great?

 

[Tiha]

Finally getting back to this project.

I got a decontamination kit.

Started putting injectors in. Cleaned the holes out with compressed air. visually inspected each before installing injector.

Lubed injector with new oil. Slide them in.
Used a little antiseeze on the hold down bolts.

Got the first 5 done, went great. Pulled the 6th out of the package and no o-ring. It happens I guess. So grabbed another injector. It will not slip in as easily as the rest did. Feels like it is hitting something solid.

I don't want to use the clamp to force it in. It was dark, late, and still hot. So I stopped.

Going to grab the Mic and compare it tonight. See if it is out of spec. I would not be surprised.

Have not started on fuel lines yet.

Still kicking around the idea if I want to put the injectors in and play with it some more or just put the entire kit in and be done with it.

Hate not knowing, but in the end it just needs to be done so I can move on to other things.

 

[Tiha]

All the injectors are in. The one that did not want to fit, well when I got home I pulled it and It still had the protective rubber cap on the tip.

So yeah, I was distracted by the previous missing 0-ring and thinking or wondering if I missed any others and did not pay attention to what I was doing.

Pulled the cap it slid right into place.

All the injectors are in. Torqued down. CP4 is in. I just put the high pressure fuel lines on. Need to tighten them.

Still have the return line to route and install.

Couple hours here and there it will get done.

So I am really nervous. I don't know how anyone can install these parts on the truck and keep them clean. Even in my garage, no wind. Little dust. You barely touch something and dirt is falling everywhere.

Before I started I read so many people complaining about this company or that. When you read through the complaints I really have to wonder if they got a chunk of dirt in the fuel system during install and created their own problems.

Pensacola diesel on BBB I think, can't remember where but it was one of the best reads. Injectors direct had some as well. Where you can follow the person making the complaint, then the company responds with, 'well we took it apart and inspected it and it had dirt in it" Or something like that.
You can follow it all the way through and kind of decide for yourself.

Today you can find complaints about any company out there as much as praises. No confidence in knowing you made the right choices.

If I don't have it running by this weekend it will probably get pushed off to the side for a month or two again. But at least the fuel system is closed up now.

 

[CarterKraft]

Not sure if this helps but we routinely do these jobs in dirt moving machines in dirt producing environments (rock pit, sand pit, ready mix yard, construction site etc.) with no problems from dirt contamination.

You have to be diligent and clean everything, keep it clean (capped/plugged) and put it together in a order that keeps you from contaminating where you have already been.

It sounds like with your level of "care" you will do fine.

IMO if you bought the whole kit, just put it all on. You can autopsy the removed parts to get a feel for what happened, I would do that regardless of if I bought the parts separately or in a kit.

I would want to know as well what happened.

 

[Tiha]

Not sure if this helps but we routinely do these jobs in dirt moving machines in dirt producing environments (rock pit, sand pit, ready mix yard, construction site etc.) with no problems from dirt contamination.

You have to be diligent and clean everything, keep it clean (capped/plugged) and put it together in a order that keeps you from contaminating where you have already been.

It sounds like with your level of "care" you will do fine.

IMO if you bought the whole kit, just put it all on. You can autopsy the removed parts to get a feel for what happened, I would do that regardless of if I bought the parts separately or in a kit.

I would want to know as well what happened.

I am in that same boat. I still want to know.

The only thing I have to go on since my injectors were not the cause of low PSI during cranking is the Inlet suction valve on the CP4.

Way back when I posted that I had read where you crack the injector line, Key on Engine off. If fuel shoots a couple inches you have a bad inlet suction valve on the CP4.

When I get it back together far enough I am going to test the new pump that way.

Only ever read that in one place, but it does seem to make sense.

External inspection of the CP4 or any other parts I removed didn't reveal a thing. It all looks good.

But then maybe I get it together and it still won't start.

Agree I am probably being over cautious. I had a shop guy do a 7.3 IDI pump and injectors years ago and he was filthy. He got done and 3 injectors were sticky. I know it was his fault. Made me realize how careless I had been in the past and how you really can mess up a set in a hurry.

But today it seems like every part you buy is hit or miss. no guarantees and I don't have time, nor do I want to do any of this again.

 

[Tiha]

As with any of my personal projects, I never get the easy ones. Like hey, here is a bad injector, replace it and boom done. Nope. not me. not ever it seems.

So here I am. to update I got a contamination kit. Because it was the best deal compared to individual parts. So I just got the motorcraft kit. Thought I would install decent brand name parts and all my problems would be gone.

Started with replacing just the injectors and rails. Just for kicks wanted to see what happens. I did all that. Hooked up the forscan. Tried to start the truck and Nothing, no change in rail pressure. Still does not build rail pressure. At all. None.

I bled it plenty. Kept cycling the key as I was entering the IQA numbers. And nothing. Just like before. Not building rail pressure.

Only code is injector pressure too low while cranking.

honestly expected that because all of the testing I had done previous to tear down said it was a failed CP4.

So onto replacing the CP4. It went very well. I have been lucky all along, no stuck injectors, everything came apart just fine.

Finally get it all back together and absolutely no change. Crank no start, not building any rail pressure. None.

I start going through all the trouble shooting again. Testing the new PCV, VCV, bleeding, purging air.

Even tried some other things. Making sure my trouble codes were cleared before cranking. In doing that I am getting MAP code and Barometric sensor code because the top of the engine is still off.
So I hooked them up and let them lay there. Can't hurt right?

to my surprise after doing so the engine started to build rail pressure while cranking. first try was like 150 psi, second try was like 250, 3rd try was like 1500 psi. 4th try it started and ran. My rail pressure was running plenty high like 6k. but bouncing around. Then the engine died.

Immediately back to crank no start, no rail pressure.

No idea if the MAP and Baro sensor had anything to do with it. I really don't think it did. but things like that distract you just enough to lose sight of the goal.

I had noticed at one point when working on the engine that with the key on, the alternator was hot. So that got me to thinking about stray ac voltage. So I disconnected it. Have the charger on the truck anyway. So no need for an alternator right now.

For kicks I pulled the VCV to inspect. Of course it was clean. While I had it off I cycled the key and a ton of fuel shot out. So it is getting fuel to the vcv and pump. My core is long gone otherwise I would have swapped the VCV to see what happens.

Keep in mind I am working on this in my spare time so i come up with an idea and test it when I can.

Started thinking about PCM. So i did my best to test that. I have 12v at the VCV. yellow wire. Even during cranking. On the blue wire I don't have an oscilloscope so I can't accurately test the PW. But I did watch the voltage change while cranking. It dropped to about 9v dc. to me this also said the PCM is trying to control the VCV and my wiring was good. I even tore apart the plug to the VCV and made sure the wires and connection points were good.
At some point I returned my PCM to stock programming. Like I said, just desperate at this point.
But regardless the PCM seems to be doing what it should. Communicating. Responding. Wiring seems to be good.

I had also removed my fuel cap before doing any of this testing. Cause you just never know. LOL.

Kind of a side note, I mentioned earlier in the thread that I had read, if you crack an injector line KOEO and fuel shoots into the air then you have a bad inlet suction valve. Well I have that with the new pump as well, so that is either BS or my new CP4 has a bad inlet suction valve as well.

So I think now I am at, a mechanically bad VCV. LPFP or maybe even something in the tank blocking flow, or faulty cp4.
Just seems strange to think I can run fuel into a bucket all day long but only have a problem with cranking the truck? I can't get past that. I have the FP gauge tapped to the windshield so I watch it just about every time I crank the engine or cycle the key.

I ordered another VCV. Be here later this week. I am about 50/50 that it will be the problem.

Kind of lean towards that because I have NO rail pressure. Usually you read about guys getting 200 psi or 900 psi or just building slow. I just get nothing, Nada. But that would mean my last VCV was bad too? Doesn't make sense either.

 

[CarterKraft]

Is it forbidden to cap the lines to the pump? Will it scatter?

Maybe get a PWM driver off Amazon and control the pump valve independently.

We usually cap the lines at the rails, I don't think I've done just the pump.

Did you autopsy the core?
That was pretty bold putting new injectors on a old pump...

 

[Tiha]

Is it forbidden to cap the lines to the pump? Will it scatter?

Maybe get a PWM driver off Amazon and control the pump valve independently.

We usually cap the lines at the rails, I don't think I've done just the pump.

Did you autopsy the core?
That was pretty bold putting new injectors on a old pump...

I would think the pump would hold it, it has to have an internal bypass.

Capping lines was in my crosshairs but I got stuck on it doing exactly the same thing. If I had seen some kind of rise in rail pressure I think I would be capping lines looking for a new injector that was bad.

Did not tear apart the old core. My time was limited. I knew I wouldn't get the thing put together for a while so I just packed it and shipped it back.

Yep, old pump and new injectors, but have to remember my fuel system was spotless. No signs of metal or rust anywhere.

I had actually thought about gutting the VCV just to test, but then I have no way to kill the engine, or what if it runs away. LOL

Think I will try this new VCV and maybe throw a lift pump on it after that. You don't know until you know.

I could hear air entering the fuel tank after I started purging the system. Or at least I think that is what I was hearing. Kind of thought that was odd, don't ever remember hearing that when i changed fuel filters and bled the system.

I changed fuel filters not too long before I started tearing this thing apart. Maybe I have a bad filter. Who knows. Getting pretty ridiculous though.

 

[CarterKraft]

I would think the pump would hold it, it has to have an internal bypass.

Capping lines was in my crosshairs but I got stuck on it doing exactly the same thing. If I had seen some kind of rise in rail pressure I think I would be capping lines looking for a new injector that was bad.

Did not tear apart the old core. My time was limited. I knew I wouldn't get the thing put together for a while so I just packed it and shipped it back.

Yep, old pump and new injectors, but have to remember my fuel system was spotless. No signs of metal or rust anywhere.

I had actually thought about gutting the VCV just to test, but then I have no way to kill the engine, or what if it runs away. LOL

Think I will try this new VCV and maybe throw a lift pump on it after that. You don't know until you know.

I could hear air entering the fuel tank after I started purging the system. Or at least I think that is what I was hearing. Kind of thought that was odd, don't ever remember hearing that when i changed fuel filters and bled the system.

I changed fuel filters not too long before I started tearing this thing apart. Maybe I have a bad filter. Who knows. Getting pretty ridiculous though.

Have you just ran the lift pump into a bucket (not put) to just check no pressure flow?

 

[Tiha]

Have you just ran the lift pump into a bucket (not put) to just check no pressure flow?

Yes. ran a hose right off the rail.

Also during PCV testing. Run a hose from the PCV return into a bucket. Watch the flow stop when you start cranking.

LPFP seems to be doing what it is supposed to.

Like I said, it would be weird that the pump does everything it is supposed to do all day long until it comes time to crank the engine.

I took the low pressure fuel lines off the CP4 and cycled the key, thinking maybe there was a blockage or restriction.
Nope it flowed out like mad.

 

[CarterKraft]

My BIL had a crank no start on a '17 ended up being a lpfp and a delaminated fuel tank.
We changed the secondary fuel filter and couldn't get it to prime even though it was running before we did that.

It pumped fuel like crazy to at the inlet of the secondary fuel filter.

 

[Tiha]

My BIL had a crank no start on a '17 ended up being a lpfp and a delaminated fuel tank.
We changed the secondary fuel filter and couldn't get it to prime even though it was running before we did that.

It pumped fuel like crazy to at the inlet of the secondary fuel filter.

I had actually thought about taking the return line off at the fuel pump and running it into a bucket.

Maybe I should try that.

 

[Tiha]

I took a day of vacation yesterday to do some other stuff. Had some time so I swapped the LPFP from my 2016 onto my 2014.

No change, still no rail pressure. So I have eliminated that. Was really hoping that would have done it.

Now I am waiting on my VCV should come today or tomorrow. If that doesn't make a difference I think I am back to a Dead CP4 new out of the box.

 

[CarterKraft]

I took a day of vacation yesterday to do some other stuff. Had some time so I swapped the LPFP from my 2016 onto my 2014.

No change, still no rail pressure. So I have eliminated that. Was really hoping that would have done it.

Now I am waiting on my VCV should come today or tomorrow. If that doesn't make a difference I think I am back to a Dead CP4 new out of the box.

I'm following your logic but even though these pumps are subject to dying they don't really not work unless they frag.

Id be checking current to the suction valve to verify it's actually doing some work before changing it or the pump.

 

[Tiha]

I'm following your logic but even though these pumps are subject to dying they don't really not work unless they frag.

Id be checking current to the suction valve to verify it's actually doing some work before changing it or the pump.

Sounds like you are calling the suction valve is what I am calling the VCV. Everyone has their own terms it seems.

It has been electrically checked. That is why I ordered a new one. Everything checks out. The PCM is trying to control it, it has voltage.

It is either dead, or something inside the pump is.

Not sure what else can cause zero pressure.

I agree, the pump is stupid, it turns, it pumps. I keep looking at it from an electrical issue, but it can certainly still be a hydraulic issue.