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Just got my 11 back from cp4 failure. Dealer had it for 7 days. They had to take the cab off the truck to get to it, so I'm guessing you dont wanna do this in your garage. Cost was close to $10K to replace the whole fuel system due to metal from the pump going through the system. Not a fun fix. Thank GOD it was under warranty.
Pulling the can is NOT normal/required to do the job. But whatever, sounds like you got it fixed on GMs dime.
 

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My 2011 LML is pushing 100k now .. still original cp4, truck is going to HSP Diesel here in a few weeks .. we are doing everything including a fast 150 but i was gonna leave my CP4 for a bit ... now after multiple threads of reading im think im just gonna bite the bullet and do the CP3 with the fast 150 at the same time ... god this project is getting expensive... i sure hope its bullet proof when im done .. i don't need a 50K hauler turned into a boat anchor by a bad fuel pump !
 

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Looking at buying a 2011 3500 DRW, one has 56K another has 89K, is there anyway to test these CP4 before buying? see if they are starting to fail??? thanks guys!
 

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The CP3 conversion definitely stings, $1600 for the pump and conversion plus I think the manual calls for 40 hours of labor. I'm doing the conversion and an AirDog II 165 4G. I'm doing a full delete as well, should have the truck back this weekend. I'll sleep better at night knowing the CP4 is gone.
 

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The cost is correct, Makes sure you get the Kit that DOES NOT REQUIRE TUNING. You can R/R the Kit in less then 10Hrs. If you are doing complete delete and keep the kit that requires tuning make sure YOU know WHAT FPR/FCA you have so the tuner can map the correctly.
 

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I just got done reading all this,im just going to take my truck to the junkyard,and go byuy a 1932 ford pick-up,im scarred my duramax is going to blow-up and kill 50-100 people


these trucks are nearly bulletproof[stock],GM has probably sold 200,000+ of these duramaxs since 2011[when they added cp4] and how many have really failed?
 

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Not likely, I just received MY 1st 504,000 mile CP4, So they can last, It was not going to go much farther, the Bushings and the rollers scar badly.
 

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FPR/FCA? The kit I purchased was from Fleece. I know that the installer and tuner are working together to make sure everything is 100% before I get it back.

In all honesty, I think the CP4s are fine for the stock LML and the lift pump is probably the best addition to aid it. I did the conversion because i knew I would be tuning the truck and throwing more power at it. I wanted to do it right the first time.
 

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Factory CP4 and CP3 have the same flow at same RPM, The CP4 cannot be modded to support additional RPM and Flow/PSI W/O raising the risk for failure and its longevity is greatly reduced. At times modded CP3s fail, but its rare and NOT common to a certain point. Lots of myths on the CP3 do to misleading advertising and marketing.
 

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So, i recently bought a 2012 LML in Nov with 113000 mi on it. Mistake 1) do your research on potential hard failures. So, I had a CP4 blowout in the middle of no where SD. Long story short, 1 700 mi tow home to diesel engine specialist because the stealership here in Ft. Leavenworth has been less than good when it comes to my truck. So, he replaced the CP4, cleaned all screens, flushed lines, dropped tank and drained and inspected, replaced a pressure regulator etc. Truck runs fine until its warmed up. Then, if you shut it off, it takes about 15 sec of the starter running to get the engine to start. Tested all the return pressures on the injectors and they are all bad. So, chalk this one up, another $8500 to get this truck running right again. Hopefully tomorrow I have a working truck. Wish I would have done my research.
I have submitted a ticket to the NHTSA because this failure occurred while on the highway traveling 70mph. Quite an alarming occurrence at that speed to say the least. GM needs to recall these things and fix this now. That is too much money to fix for just 1 part failing. I want to love this LML but I could have bought a brand new one now at this point. Definitely getting a lift pump to prevent this from happening again.
 

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Glad I have a LMM with a CP3...
 

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So, i recently bought a 2012 LML in Nov with 113000 mi on it. Mistake 1) do your research on potential hard failures. So, I had a CP4 blowout in the middle of no where SD. Long story short, 1 700 mi tow home to diesel engine specialist because the stealership here in Ft. Leavenworth has been less than good when it comes to my truck. So, he replaced the CP4, cleaned all screens, flushed lines, dropped tank and drained and inspected, replaced a pressure regulator etc. Truck runs fine until its warmed up. Then, if you shut it off, it takes about 15 sec of the starter running to get the engine to start. Tested all the return pressures on the injectors and they are all bad. So, chalk this one up, another $8500 to get this truck running right again. Hopefully tomorrow I have a working truck. Wish I would have done my research.
I have submitted a ticket to the NHTSA because this failure occurred while on the highway traveling 70mph. Quite an alarming occurrence at that speed to say the least. GM needs to recall these things and fix this now. That is too much money to fix for just 1 part failing. I want to love this LML but I could have bought a brand new one now at this point. Definitely getting a lift pump to prevent this from happening again.

Your deisel specialist should have known that the injectors were NFG after the pump bailing on you and replaced the. From the get go. Did he replace the return line? That thing is like an octopus and you'll never get all the metal particles out of it. Fuel rails should have been replaced too... It's an expensive repair to do properly, and doing it improperly can lead to a repeat failures.
 

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Didn't change the fuel rails, did change the return lines because it came with another part he ordered. We talked about the injectors but he was hoping that they survived so was going to do the other things first. As others have stated some times you can get away with just changing the pump. Now, I realize that 95% of these that is not the case so in hind site, I wish he would have just ordered them and had them on hand and ready when he finally did realize that the injectors were fouled as well. That would have saved me a day but right now I just need my truck back. I am supposed to be moving tomorrow and need my truck yesterday.
 

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I think one of the big keys to CP4 longevity is the lubrication of the pump, todays fuels simply do not have the lubricity that Bosch spec'd for the CP4, and a fuel additive is required. If you use an additive, like Opti Lube XDP or another high quality additive, you really should not run into any major issues.

A lift pump, to me, is only necessary when running a tune and you are draining the rails of fuel since the CP4 can't keep up with the required fuel requested.

The 'exploding' CP4 is prevalent in all major diesel engines, VW, Dodge, Ford.

If you are stock and worried about the CP4, just use a good fuel additive and you should be fine. It's cheap insurance.

Chris
 

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I just purchased a 2016 LML and have had Opti Lube in since tank #1.

I agree with other in that you need to take what you read online with a grain of salt as people due over blow things.

That said a potential failure sits in the back of my mind. I am looking into lift pumps as an added layer of security.

The only thing holding me back is potential if not automatic warranty voiding.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 
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