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RCD CPX--high pressure fuel pump disaster

noirtier1

Member
Joined
Feb 18, 2024
Member Number
7499
Messages
8
Good afternoon all. Anybody out there have experience with your high pressure fuel pump splitting literally in half? Causes? I had this happen. I have my high pressure fuel pump go out replaced it with a aftermarket CPX. No other aftermarket changes and fuel system or engine. Engine ran perfect had zero compression issues, always ran Schafer oil, has A bank's air intake I have put on it as well as have my hot and cold side changed when I bought the truck. Truck is fully deleted and has an ezlynk for tuning. Don't run a hot tune or anything crazy. Just towing versus Street tune. Basically After CPX was installed I was going down the road towing a empty trailer nothing heavy about 4K pounds all the sudden here are awful noise and motor shuts down. I never had metal in any of my oil changes or anything like that, but shop called me to tell me that motor was locked up. After another round of diagnostics on it they took the gear off the front of CPX and seen that it was split in half. So yet another set of fuel rails lines etc and the CPX reinstalled. Then they check the compression on the motor all the sudden I have compression problems and and being told I need a new motor. Awfully strange that the motor had zero problems before and zero compression issues. And never have metal in anything. I run a fuel treatment every tank to ensure water is being removed etc. Truck has only ever had Ford oil filters in it as well. And again as I previously stated never had drivability problems or loss of oil pressure either.
Any input would be appreciated. While I am not completely diesel dumb I am new at owning a diesel. There seems to be a conflict of opinion out there on what happened first the CPX splitting in half causing the motor problems or the motor causing the CPX problems. Just for the record as far as maintenance this truck is very well-maintenanced as I'm a business owner and use it for towing daily. I'm one of the only female owned outdoor construction companies and need to be able to rely on my vehicle. As a single female you could imagine that as I said I'm not completely diesel dumb but at the same time I'm not a mechanic either. Truck gets a fuel filter every other oil change, with oil changes at 5K and always recharge after cleaning Banks air filter. I have a Venturi reroute also... But it was done quite some time ago and truck ran perfectly fine up until this point. I've done other things to it like putting a master cylinder in it and new hydro pump, brakes but that's about it no major catastrophes until this.
 
If the fuel pump sized it could have spun the timing gear on the crankshaft and that is why you are showing compression issues.
Fixable if that gear spun
 
They pulled out a CP4 to install a modified CP4? :laughing:




They should have installed a DCR pump if they had a clue..... Good luck
 
Tiha said:
If the fuel pump sized it could have spun the timing gear on the crankshaft and that is why you are showing compression issues.
Fixable if that gear spun
Click to expand...
So I m looking for insight and understanding. I'm not a mechanic but I'm a quick study.
When I had the original new/modified CPX was installed in my truck a few months prior to this catastrophic failure --the truck got new injectors, rails, lines, filters and a brand new fuel tank installed on it as well.
When the shop contacted me at first over my truck and told me the motor was locked up, I asked him how that could even be possible considering when this happened I was going down the road and actually had to shut the truck off because it was losing power after I heard the very large noise under the hood. At that time, they did say they hadn't finished diagnosing it and they had a couple more things to do/check but wanted to call me with their first impressions which I had asked them to do. On the next phone call they had removed the gear off the front of the high pressure fuel pump and seen that the cpx was split completely in half. They also stated that the motor would freely turn by hand.

Because the motor would freely turn by hand and the high pressure fuel pump was split in half they contacted the manufacturer and a new one along with new rails new injectors new lines etc was sent and all these parts installed on the truck. After installation my guess is they tried to start the truck or we're doing more diagnostics on it and at that point, I got another phone call saying that the motor will turn over but they think the motor is shot. I had no metal shavings in any oil change, no loss of power until this event, no oil loss, and no oil pressure loss. My oil temps were running 198, 202 and 212 when towing heavy. So nothing crazy really going on there either. Clutch fan working fine on the truck anytime oil or trans temp was over 195.

I asked the mechanic if when the high pressure fuel pump split, if it could have sent trash/metal somehow into one of the injectors and washing the cylinder down creating hydrolock?? After that question he said no and eventually the fuel would have went out of the cylinder. After speaking with somebody else with the above information they had a complete opposite opinion that if the cylinder was either way over full with fuel or had something else going on in it it was possible to have a piston break causing a chain reaction. Fast forward 2 weeks while they're waiting on the motor to be ordered and shipped, I stopped by after speaking with a senior technician from Ford (basically a specialist for odd cases) and he said that it was probable high pressure fuel pump grenaded the motor. Then stated half the mechanic pull the heads as well as results of compression test. I stopped by the shop to have that conversation with the mechanic, mechanic then states that would not explain crank walk that it now had. (The crankwalk issue was discussed with me at the same time they said it needed a motor and that it would turn over and not run along with the fact that there was a cylinder with under 100 lb of compression).
Can somebody out there that is more diesel smart than me help make sense of all this? How probable is it that the high pressure fuel pump splitting in half caused the catastrophic motor failure? Understand that when this happened I was driving down the interstate with a very light empty trailer behind me 3800 lb nothing crazy and doing 70. Truck was pulling fine no hard shifts, no loss of power just literally as I went to go up a very slight incline all the sudden heard the noise and knew something was massively wrong as truck was losing power I pulled to the shoulder and turned it off. No fluids underneath it, new fluids down the road none on the trailer behind me. And no signs of fluid lost. Just seen one puff of white smoke as I got stopped and once truck was turned off you could smell unburnt diesel
 
noirtier1 said:
So I m looking for insight and understanding. I'm not a mechanic but I'm a quick study.
When I had the original new/modified CPX was installed in my truck a few months prior to this catastrophic failure --the truck got new injectors, rails, lines, filters and a brand new fuel tank installed on it as well.
When the shop contacted me at first over my truck and told me the motor was locked up, I asked him how that could even be possible considering when this happened I was going down the road and actually had to shut the truck off because it was losing power after I heard the very large noise under the hood. At that time, they did say they hadn't finished diagnosing it and they had a couple more things to do/check but wanted to call me with their first impressions which I had asked them to do. On the next phone call they had removed the gear off the front of the high pressure fuel pump and seen that the cpx was split completely in half. They also stated that the motor would freely turn by hand.

Because the motor would freely turn by hand and the high pressure fuel pump was split in half they contacted the manufacturer and a new one along with new rails new injectors new lines etc was sent and all these parts installed on the truck. After installation my guess is they tried to start the truck or we're doing more diagnostics on it and at that point, I got another phone call saying that the motor will turn over but they think the motor is shot. I had no metal shavings in any oil change, no loss of power until this event, no oil loss, and no oil pressure loss. My oil temps were running 198, 202 and 212 when towing heavy. So nothing crazy really going on there either. Clutch fan working fine on the truck anytime oil or trans temp was over 195.

I asked the mechanic if when the high pressure fuel pump split, if it could have sent trash/metal somehow into one of the injectors and washing the cylinder down creating hydrolock?? After that question he said no and eventually the fuel would have went out of the cylinder. After speaking with somebody else with the above information they had a complete opposite opinion that if the cylinder was either way over full with fuel or had something else going on in it it was possible to have a piston break causing a chain reaction. Fast forward 2 weeks while they're waiting on the motor to be ordered and shipped, I stopped by after speaking with a senior technician from Ford (basically a specialist for odd cases) and he said that it was probable high pressure fuel pump grenaded the motor. Then stated half the mechanic pull the heads as well as results of compression test. I stopped by the shop to have that conversation with the mechanic, mechanic then states that would not explain crank walk that it now had. (The crankwalk issue was discussed with me at the same time they said it needed a motor and that it would turn over and not run along with the fact that there was a cylinder with under 100 lb of compression).
Can somebody out there that is more diesel smart than me help make sense of all this? How probable is it that the high pressure fuel pump splitting in half caused the catastrophic motor failure? Understand that when this happened I was driving down the interstate with a very light empty trailer behind me 3800 lb nothing crazy and doing 70. Truck was pulling fine no hard shifts, no loss of power just literally as I went to go up a very slight incline all the sudden heard the noise and knew something was massively wrong as truck was losing power I pulled to the shoulder and turned it off. No fluids underneath it, new fluids down the road none on the trailer behind me. And no signs of fluid lost. Just seen one puff of white smoke as I got stopped and once truck was turned off you could smell unburnt diesel
Click to expand...
It's gonna be hard to armchair diagnose this but if the crank has excessive end play/thrust then something's up.

As Slowpoke said don't put a cp4 of any flavor back on it, look for the s&s - DCR variant.

There's a lot to this story, you might be getting enough info to just tell you that you need a engine not getting in the weeds, but if you are going to intervene you need to get your hands on the parts.
 
A damaged injector filling a cylinder with fuel and damaging the piston or rod is very possible.

But that would not affect the other cylinders. Especially in the time frame they have had it.

You are not getting the full story, in fact the repair shop may not even know the full story. The person you are dealing with at the shop may be getting the information to you 2nd or 3rd hand even.

Shops don't like to do diagnostics on something like that. They see the problem and they want to fix it as quickly and cheaply as possible. They make no money tearing the engine apart to see what really happened inside.

Now if you are approaching this from a legal standpoint, as if you want to get warranty or sue for damages, then you should contact a lawyer and get them involved now. That way you can keep the engine from going back as a core before it is diagnosed.

But keep in mind that is a gamble in itself. You may spend $10k trying to find the answer and find out that it was just a freak accident and nobody is to blame.

What year is this? The 2011-2012 had valve train issues. Up to 15 they had turbo issues. Seems like each year had their own set of unique but common issues.
 
Mine was a 2018. Not sure if you see my previous post but had zero metal anywhere prior to this event. Never had any form of performance issues prior. The crazy thing is the truck was running and just losing power very very quickly after CPX split in half. I physically had to turn the truck off after I pulled over to the side after hearing a absolutely huge noise out from underneath the hood much like a noise you would hear when a motor is a*locking up, b* piston is breaking, c** crank has issues. It was a very loud metal to metal noise but more of a huge thump not anything high pitch or crazy like that. I had my ezlynk in the console so I went ahead and plugged it in got all sorts of crazy codes coming off the fuel system. Which of course after the shop finally saying they removed the gear off the front of it and seen that it was split in half made 100% since that I was getting in fuel error codes. I maintenance my truck very very well because I towed with it a lot and need it to be dependable. Same shop had it to fix several other things after I bought it. I myself have only had it for 50k miles. He might be able to see my other post on what happened with it. But originally they thought the motor was locked up until they removed the gear off of the front of the high pressure fuel pump and then the crazy thing is is the motor would still turn over. That's when they said they did a compression test and a cylinder was getting less than 100 pounds of compression. I just find it extremely suspect that something went so wrong that it split the high pressure fuel pump in half and it wasn't somehow the cause of the motor having a catastrophic failure. I could see it if I had had any form of prior motor problems but seeing as I didn't and additionally they had just had it a thousand miles prior to put a hydro boost and master cylinder in the truck and they drove it afterwards they would have definitely said something about it having issues. I never had any fuel pressure loss that I could tell but as far as the truck diagnosing itself and all gauges, my oil pressure never dropped until this happened. In fact to be honest I never had any irregularities on anything in the truck it was just all in one second... it happened. I was told after the CPX was removed from the truck that the manufacturer of the CPX had a batch of the very first production run that they had a lot of catastrophic failures with. My CPX was literally one of the first off of production. In fact I believe mine was one of the first 10 made if I remember the conversation correctly. Rcd sent a new set of rails, injectors etc after this CPX split in half so it's just an opinion but they obviously knew something was wrong in the unit or that it was one of the defective ones or why would they be sending out a whole new fuel system to the shop to have it installed? Again just looking for understanding as I'm not a mechanic and trying to make sense of the whole thing
 
Also, there was a Ford master tech on a different forum that chimes in and said to have the shop pull the heads and see if a cylinder got washed down from HPFP failing, have compression test ran in every cylinder and documented. Is there anything else out there that can be checked or tested to see if HPFP caused the catastrophic failure to the motor. I know the 2018 6.7's aren't really know for grenading themselves.... Even our diesel shop said this was odd
 
Looks like you got it covered but, yes I was about to add before this second post, you need compression numbers on all cylinders not just one.

If it is low in one cylinder, pull the head, or at least the valve cover and see what you see.
If low in all cylinders, pull both valve covers and see or actually I would be more interested in pull the front cover of the engine and looking at all the timing components.

Maybe the camshaft is broken. Which would have destroyed every valve in the engine.

You said something earlier about crank walk. Are they saying the crankshaft has too much in and out play? Or any idea what they meant by that?

But all of that labor is going to be additional cost on top of the repair.

It could be that there was a cylinder hydro locked and when the shop tried to start the engine they broke the piston then. It doesn't happen often, but it does happen.

So basically we don't have enough information yet. If one cylinder is all that is bad, I would think the truck would have started up after the CP4 replacement. Even with hydro lock and a broken rod or piston.
That would make me think it is more than one cylinder. Which again would point to the CP4 seizing before it broke and throwing the engine out of time somewhere.

Pretty hard to troubleshoot stuff over the internet.
 
noirtier1 said:
Mine was a 2018. Not sure if you see my previous post but had zero metal anywhere prior to this event. Never had any form of performance issues prior. The crazy thing is the truck was running and just losing power very very quickly after CPX split in half. I physically had to turn the truck off after I pulled over to the side after hearing a absolutely huge noise out from underneath the hood much like a noise you would hear when a motor is a*locking up, b* piston is breaking, c** crank has issues. It was a very loud metal to metal noise but more of a huge thump not anything high pitch or crazy like that. I had my ezlynk in the console so I went ahead and plugged it in got all sorts of crazy codes coming off the fuel system. Which of course after the shop finally saying they removed the gear off the front of it and seen that it was split in half made 100% since that I was getting in fuel error codes. I maintenance my truck very very well because I towed with it a lot and need it to be dependable. Same shop had it to fix several other things after I bought it. I myself have only had it for 50k miles. He might be able to see my other post on what happened with it. But originally they thought the motor was locked up until they removed the gear off of the front of the high pressure fuel pump and then the crazy thing is is the motor would still turn over. That's when they said they did a compression test and a cylinder was getting less than 100 pounds of compression. I just find it extremely suspect that something went so wrong that it split the high pressure fuel pump in half and it wasn't somehow the cause of the motor having a catastrophic failure. I could see it if I had had any form of prior motor problems but seeing as I didn't and additionally they had just had it a thousand miles prior to put a hydro boost and master cylinder in the truck and they drove it afterwards they would have definitely said something about it having issues. I never had any fuel pressure loss that I could tell but as far as the truck diagnosing itself and all gauges, my oil pressure never dropped until this happened. In fact to be honest I never had any irregularities on anything in the truck it was just all in one second... it happened. I was told after the CPX was removed from the truck that the manufacturer of the CPX had a batch of the very first production run that they had a lot of catastrophic failures with. My CPX was literally one of the first off of production. In fact I believe mine was one of the first 10 made if I remember the conversation correctly. Rcd sent a new set of rails, injectors etc after this CPX split in half so it's just an opinion but they obviously knew something was wrong in the unit or that it was one of the defective ones or why would they be sending out a whole new fuel system to the shop to have it installed? Again just looking for understanding as I'm not a mechanic and trying to make sense of the whole thing
Click to expand...
What did RCD say about the failure?

CPX Pump – RCD Performance

rcdperformance.com rcdperformance.com
 
sounds like you've been taking it to the dealership for service and repairs?

What area are you from? any good diesel performance shops?

from my experience, i'm only taking a diesel to a diesel specific shop

and then even when it comes to diesel specific shops, a diesel specific shop that specializes in my truck
 
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