Extended cranking, fuel system tests.

[lincolnlocker]

You can reset alm the adaptive tables with forscan and basically force a relearn.

Also, not sure why nobody has said anything but low pressure fuel should be 80ish psi all the time.

You have a leak between the tank and lpfp or its worn out or the control valves on the motor are stuck open allowing the low pressure.

If it where me, i would put a new lpfp on it being everything else looks clean in all of your pictures.

And use a good fuel additive every tank.

Cp4.2 might actually have taken some abuse with the low psi fuel going to it.

 

[Tiha]

Also, not sure why nobody has said anything but low pressure fuel should be 80ish psi all the time.

Exactly, I was hoping someone would see that and elaborate on it.

That reading is taken off the high pressure rail. It is not the switch that triggers the LP alarm and puts it in limp mode.
That switch is calibrated to 30K psi. So a little tolerance is understandable. Reading 42 psi on the scanner as opposed to even say 80 psi. The sensor could be off by that much. That is what .02% tolerance

understandable isn't it?

And if my PSI was actually less than 53 then the switch would close and I would get the alarm. So the switch would have to be bad as well.

I found one thread online where the person said his KOEO psi reading was 350. Like on my 2016. He said he replaced the sensor and the new sensor said 0psi. So he put the old sensor back in and kept running it. LOL

and I had thought about just throwing a pump on it but that is a $500 gamble in itself.

When I pinched off the return line the fuel rail pressure went to 96 psi. according to the scan tool. The LPFP is internally regulated at 120 psi. Taken that information and apply it to the ASSUMED variance in the pressure sending unit it made sense that the pump was working properly.

Regulated at 120 but reads 96 psi. 24 psi off.

now add that 24 psi (variance) to the 42 I measure and get 66 psi. Within spec.

To me the logic was sound. Maybe I need to make an adapter and put a manual gauge on it. Yuck, I don't want to.

 

[Tiha]

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

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

 

[lincolnlocker]

You're not ok if its still a long crank. Not sure what the specs are but low pressure fuel should be at and stay at 80psi at idle or wot. I can see a drop to 76psi every once in a while but that is rare. When my brothers lpfp pump went out, it was doing exactly what yours is doing. It tripped the low pressure warning like once. Threw on my spare lpfp off my 12 because i thought i had an issue there back when i had it. ***er holds 82psi all day long now. My turning might be a bit more aggressive than his as his never drops below 80psi.

I told him i wanted to trade it for mine. Lol.. my 15 has 250k on the clock. That 12 pump has like 110k on it. My brothers lpfp tanked at 90k and thats a 15 as well.

 

[Tiha]

I was supposed to have a fuel pressure tester adapter by now but it hasn't even shipped yet.

I tried to build one.

Looks like the upper fitting is a 12mm found a quick connect that works on 1/2" or 12mm. It seems to snap onto the fuel filter just fine.

But the Steel end, 12mm, to make the adapter is currently not available. 1/2" steel is too big to fit into the factory fitting.

So I thought I would just make a hose to snap in place of the return line.

Nope, the other end is like 9/16" or 14mm. I cannot find that quick connect anywhere. 5/8" is available, but that is too big.

What a joke. Sick and tired of amazon and their fake reviews and their fake ship dates.

Amazon says carrier has it. USPS says they have not gotten it yet.

Granted there have been gaps in shipping information before but not like this.

 

[Tiha]

Tried to move the truck last night. Would not start. Now I am pissed.

Was running, pulled return line to try and make my own pressure adapter. Which I failed at. Put line back on because I can't keep waiting on this stupid adapter forever with this thing in my garage.

Now I can't get the fuel system purged. Maybe that is a sign of bad lpfp but online seems to be fairly common thing. Even with brand new LPFP or that and an entire decontamination kit.

With the return line completely off the rail pressure still reads 42 psi. So certainly some inaccuracy there.

Cranking my PSI never increases, which is jumped right up before. I am sure that is because it is air bound.

So Now I need to try and purge the system just to get it running.

The fuel pressure adapter I ordered now finally shipped. says arrives next week. We will see.

When I was doing fuel pressure tests last fall I clamped a hose on the return line and ran it into a bucket. During that test I clamped off the return hose completely to test dead head pressure.
So now that I think back on that. I could have built a gauge adapter and just hose clamped it in place.

Now I don't care, just want to get it running and get it out of the garage so I can get started on other projects I am way behind on.

 

[Tiha]

Well low pressure is 62 psi per maual gage.
Still won't start.

Rail psi not coming up.

Pulled intake again. Pulled flow control valve. Still clean. Pump full of fuel.

Found this.

"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 tried it and my fuel definitely shoots into the air a few inches.

According to that my cp4 went bad. Sitting in my garage. Nice.

Can anyone confirm? I am not even sure what to check next.

I unplugged the pressure sensor so it showed 30k rail pressure. Still no start.

 

[Powerstroke Cowboy]

I have seen pickups go.from running to not running in seconds due to a failed hpfp. The one was shut off, started up and maybe backed up 40 feet and it shut of and was done. No hints of failure before.

These things are all but impossible to diagnose over the e-net.

Do you have metal shaving caught in the screen of the metering valve? That's on top of the cp4.

 

[Tiha]

Do you have metal shaving caught in the screen of the metering valve? That's on top of the cp4.

It hard to diagnose over the internet. Whether it be terminology, or understanding, or just not looking at the same things everyone else does.

Just like in this case. I can find one person that explained conditions that matched mine. Everything else I find they all have metal shavings. Mine is clean.

It is such an emotional roller coaster. Going into this I thought I would end up needing a decontamination kit. Then farther into is, maybe a couple injectors. Then maybe just a LPFP and at the end couldn't find anything wrong.
Now back to needing a CP4.

After measuring fuel pressure. 62 psi by manual gauge and still not getting it to start I pulled the intake again, pulled the flow control valve again. It is clean, no metal shavings.

The only thing that makes sense is the suction valve failure in the CP4. I should have gotten a picture of the fuel flowing out. Maybe I will before I tear it apart yet.

I tried to pull the pressure regulator off the Left rail, got the fender well out. Tired to get the return line off to do a flow test. I couldn't get it.
Got the regulator loose. But then found out you can screw it out of there without pulling the hold down for the injector right there, or pulling the fuel rail loose. So I left it.

Threw everything in back of the pickup and pushed it outside. I am out of time.

Guess I will put a CP4 in it. But now, which one?
It's not like I will probably put another 100k on this truck. Not increasing hp or anything.

There is $700 remans that it seems nobody admits to using. Then the New factory replacements for $1000, then all kinds of options claiming to be better.

 

[DEEZUZ]

The regulator on the rail comes out. I even bought a special wrench for it so you don't have o remove anything else.

 

[Powerstroke Cowboy]

You could very possibly have a bad suction valve. If your test all point to it. Then that should be the culprit. If that's the case you shouldn't have to worry about a contaminated fuel system.

 

[Tiha]

The regulator on the rail comes out. I even bought a special wrench for it so you don't have o remove anything else.

I guess I need to look for a video or something. I didn't try to force it past the injector hold down, maybe a little push and it would go.

Thank you.

 

[Tiha]

You could very possibly have a bad suction valve. If your test all point to it. Then that should be the culprit. If that's the case you shouldn't have to worry about a contaminated fuel system.

Had someone tell me to just replace the suction valve, but really with all of the horror stories I have read probably time to just throw a pump on it.

Seems like the RCD CPX is very popular. I need to research it some.

And yes I am thankful that I don't need to do a whole system. This whole thing is just so weird though.

Probably be a couple weeks and I will order the pump and push this thing back into the garage.

 

[sootie]

Go exergy or OEM

 

[ncollins64]

I second sootie, if it’s available exergy all the way for everything I have. There quality and customer service is awesome

 

[DEEZUZ]

Are the s&s kits just not available yet?

I wouldn't have an issue installing an OE, aren't they like $700? That and a disaster kit and you'll be fine.

 

[DEEZUZ]

I'm just having hard time seeing this entire issue being a hpfp

 

[Tiha]

I'm just having hard time seeing this entire issue being a hpfp

I always have too.

Ordered the 30mm crows foot for the DRV or pressure regulator on the Left rail. Should be here today. Figured I need to test it and inspect it to know for sure. I had used an air hammer to break it loose. Figured I better get the right tool to tighten it properly when I get to it.

Hate not having clear cut information. Was talking to a friend of mine that works for a diesel specialty shop. I hate doing that. I am sure he is sick of people asking just like I am.

But he said, put a HPFP on it. Even if it doesn't need it. Just do it now. He said in a situation like mine that is where they would start because that is what causes the most problems. You read online and people say 99% of failures is from this or that.
He said, you cannot predict how or why a CP4 will fail. Just like an engine that can spin a bearing, have a flat lobe on a cam, bust a valve spring, foul a spark plug, or burn a plug wire. Too many variables.
He works on everything so he hated the CP4 long before Ford started using it. LOL.

More than once I wanted to just tow the truck to him but didn't think I would ever need to get into it this deep. Now I am kind of there.

You can buy CP4s from $700 for cheapest remans, to $2000 plus.

Was kind of leaning towards the RCD CPX found a couple people that have actually put them in and were happy. I will have to look into the exergy.

Seems like there is a lot of options in the $1000-$1200 range.

My rails are flooded with fuel, the LPFP is maintaining 62 psi. It just about has to be the CP4. I am not sure the pressure regulator could cause this. But I will test it first.
I tested for return flow from injectors. Even if for some strange reason one or two started bypassing the CP4 should still overcome it and I should see pressure.

Have a hard time believing that even with a bad inlet suction valve it won't build some kind of pressure.

 

[Tiha]

Friend of mine just called me back from the diesel shop said he had to get his mind back to the Ford mindset and after talking with his co workers. One of the reasons I hate calling him is because they see the worst of the worst. They have dealerships tow stuff into them when they can't figure it out.

They said I need to check the pressure control valve on the left rail. It most certainly will create a no start condition. But that it is odd I don't see any blip in rail pressure and that would indicate the Pressure control is probably not the cause but still you don't know until you flow test it. To them pressure control valve is a common failure.

Next he said the flow control valve in the top of the pump. He said they don't fail often but they do fail, if my screwing with it caused it to fail or stick closed that would most certainly cause exactly what I am seeing and explain the suddenness of it all.

Asked him about the "inlet suction valve bad" test I did with the flow shooting out of the injector. he said they never heard of that. So don't take that as a fail indicator.

He said, pull the injectors and let him bench test them. Since the injectors need back pressure to operate properly my return flow test was worthless. Well he didn't say that, but I get the idea. They have to be tested properly and that they do frequently find bad injectors, they pop once or twice and stick, dumping fuel out the return. He also added the caveat that he doesn't know the back story of the injectors he is often testing, but from his point of view 6.7 injectors fail all the time.

Added; as you can see in most cases people that put in a decontamination kit even with a Clean flow control valve will have fixed any one of those issues and more. But for someone that wants to actually find the problem I have a lot of troubleshooting to do yet.
And at the end of the day it could still be a failed CP4.

Not sure what I will do first. Kind of wanted to write it all down, hoping to not forget anything since I don't know when I will take up this project again. All I can think is crap, If I pull injectors then I just as well better do valve cover gaskets and something with the CCV. then why not glow plugs too?
It just never ends.

 

[DEEZUZ]

My first thought was having a shop bench the injectors. There's a reason the return test doesn't really exsist outside of the bench. We run these all day long for customers