LML CP4 failure tear down and why your 11-16 Duramax needs a lift pump!

Figured I would show first hand what to expect when you have a CP4 failure and what is actually going on in this pump when it fails. This is a 2011 2500HD with about 100k all stock. We will be upgrading to a CP3 and running a lift pump with some other upgrades along the way to keep this truck going.
Cp3 conversions can be purchased on our website-
www.racereadyfab.com/collecti...
Also check out our article on this topic-
www.racereadyfab.com/blogs/ne...
We hate to bring this up to every customer that walks in with a 2011+ truck and don’t mean to scare or make a sale which steered me to making this video and publishing the article on my website. With some online research many people soon understand why I bring it up all the time.

[@mariusg79]

Thanks for training, I need your opinion regarding a situation with this kind of pump on a new vehicle. I have noticed on the inlet part of the pump that there are some spots, drops and can not tell whether is is leakage of fuel or vasseline leaking from that inlet. The huse is ok, there is no leakeage only at the base of that metalic inlet. The service dealership could not tell either, told me to wait.

[@jeremybroderick9465]

get the Exergy FCA/MPROP Part number E05 10505 for your LML saves the injectors when the CP4 fails

[@davidroberts168]

I just replaced my regulator on my CP4 piece of crap. I replaced it with exergy system saver. It will not stop the CP4 it from taking a shit but it will save you about $8000 because it actually has a better screen then the stock regulator. The stock one has a 80 micron screen the one I replaced it with has a 25 micron screen, and it is doubled, so it will stop the metal shavings from going into your fuel, rails and injectors which will save you a hell of a lot of money if you don’t have a warranty have a good day.

[@tonymunn]

Thank you looking at a high mileage 2012 LML and if all the injectors are balanced, the first thing I'm doing is installing a lift pump.

[@Shad0wC0mpany2]

So it goes without saying that a CP3 is well worth the upgrade, and the peace of mind knowing that it is less prone to the failure of these CP4 models justifies the price and time of the conversion. But Is there the potential for headaches with rail bounce on the LML tuning once the pump is installed?

[@harrystamper2665]

Re the comments below stemming from Betty's view that the problem is 'from the pistons getting sideways in the bore of the pump', I think the sideways condition arises from other causes such as debris and is not a root cause in itself. There is a considerable spring force holding the piston and roller firmly against the cam so, for example, if the piston roller were rising up the cam profile, the only way the roller could 'twist' would be for one side of the roller to rise higher up the cam profile and it cannot do so because of the spring loading. There are only two points when the piston/roller could twist and they are when the cam is momentarily at either the top or bottom of the cam profile, and it has not the time to rotate nor the forces applied to do so. BUT, if there is debris between piston and cylinder wall then the piston could jam and lose contact with the cam and then perhaps rotate. This could give the impression on strip-down that the twisting of the piston/roller had been the cause of the problem. Why do I feel convinced about this? Because there are literally thousands and thousands of these pumps operating perfectly well in most parts of the world. To me the root cause will be found in what is different between operating in the USA and other parts of the world - and I think most people (sufferers) know the reason! Very good video with very clear pictures of all components - many thanks.

[@jimclark4489]

Nice video and useful information. Thanks for producing it. Just one suggestion - try mounting your camera in a location other than your bench. It'll prevent jarring the image when an item on the bench is moved.

[@sfcjones2590]

Another reason why I am keeping my 2009 Duramax

[@truckdriver4323]

08 with over 450K. Still running like a champ. 👍👍👍

[@gulfmaster4189]

Took preventative measures early, installed FAAS lift pump and Exergy metering valve at 80,000 miles, added fuel additive after every fuel fill, at 120,000 miles, did a CP3 conversion, never had a problem with CP4 but I feel more confident now, anyone want to buy my CP4 pump? Runs like new🙂

[@kamrinwoodward5822]

what lift pump did you get?

[@gulfmaster4189]

@@kamrinwoodward5822 FAAS

[@wallheadkdir]

Excuse my ignorance but is this down in the tank? I have a 2016 2500hd duramax with 65k do you think it might be to late to add a FASS system?

[@dirty3000]

Dam man I’m scared as fuck now🤣 KZbin got me in a rabbit hole for the dang cp4!

[@cesarjorgemurillobarientos1813]

very good

[@mikebarcus1594]

My tow truck just blew the cp4 a week ago. We swapped to cp3 and it seems to run much better. I don’t think the owner had the tank dropped though. New injectors and fuel rails were done. I wondering if the cp3 sucks up more fuel because I constantly get the change fuel filter message if I get on it even with a new filter. I hope they did it right repair was 9600

[@wallheadkdir]

😲 OMG yeah I'm gonna be getting on this! That is an insane amount of money for a repair

[@shawnpruner]

Have you ever seen a broken cp4 pump cam gear broken?

[@Franklinveterinarycenter1of4]

OK what is wrong with replacing the FPR and screens and changing the fuel filter a couple times during the first 50 miles of driving. Those injectors can be flushed out along with the high pressure lines and return lines. The tank, you can attach a super strong magnet to and potentially harness all minor metal filament from getting into the fuel filter. Hold off on lift pump till the tank filaments are cleared.

[@pvcarmon1]

Why in the "F" would Bosch reinvent the wheel and produce that POS! That major screw up hurt a lot of loyal Ford, GM, Nissan and who knows how many other folks.

[@Trident_Euclid]

I think it's because of the newer emissions requirements

[@logancooper2326]

It wasn’t a bad pump it’s to blame on poor quality American deisel it’s a German designed pump and they have better fuel in germany

[@CondoreComputing]

It's definitely not emissions, the CP3 pumps are more efficient, take less power, can produce higher pressures and are reliable. They designed the CP4 because it's cheaper, lighter, less moving parts. Quality in comparison to the CP3 is garbage. But its the vehicle manufacturers that jumped on the new pump desighns fault. They could have specced a different design from Bosch, knowing that our diesel fuel is.much lower quality. It's even a problem on VWs and is the reason I'm doing a CP3 retrofit.

[@Heywoodthepeckerwood]

@@CondoreComputing wrong. It was made for the European market. The American government mandated ultra low sulfur diesel. Sulfur is the main lubricator in diesel fuel. They don’t have issues in Europe or anywhere else the damn EPA doesn’t have jurisdiction.

[@Heywoodthepeckerwood]

@@logancooper2326 American diesel ain’t poor quality per se. it’s the fact that it is too clean. The epa mandated ultra low sulfur. Under 15 PPM Europe hasn’t made that mistake yet.

[@JerryJrsGarage]

Ok but what would a lift pump do to help? The CP4 has aluminum bore which does not do well with water intrusion in time so does the lift pump just help postpone this wear? I mean still it will fail in time no doubt.

[@RaceReadyFabrication]

Jerry Jrs Garage the theory behind the lift pump is to stop contaminates and water from ever getting that far which will greatly reduce the chance of failure. But I see what your saying it is just a poor design but without a cp3 conversion the lift pump is your next best option to greatly reduce wear in your cp4 pump.

[@JerryJrsGarage]

Race Ready Fab Yeah I suppose it would help to some extent. I am going to do a lift pump first then use additives in the mean time. I appreciate this video. Thank you!

[@diesellady1]

I know I will get haters, but I dont think this is caused by lack of lubrication. Although that doesn't help. I think it is from the pistons getting sideways in the bore of the pump. There is no keyway to stop them from spinning, and when the piston turns sideways it doesn't roll over the cam any more, just chews it up, or breaks it off. I tore one apart and found the rollers were chewed up bad. If they would make the piston so it doesn't turn in the bore, it would prob solve the whole issue. Just my 2 cents. ")

[@ChrisSmith-ig9jq]

what about to cp4 running in Europe? were the sulfer content is around 500ppm vs 15ppm

[@diesellady1]

I'm sure lubricity helps, but this would not happen at all if there was a keyway.

[@ChrisSmith-ig9jq]

@@diesellady1 makes sense

[@ol-man-duffyj688]

Not a bad theory, I’d expect to see flat spots on the pin sitting in one spot then.

[@FarmerSteveO]

@ Betty Sutherland you are right on point. The two CP4’s I have personally whiteness fail have been from the piston turning and the roller galling the cam lobe or vise versa which then fails and sends metal through the entire system. Every shop I have talked with said these bottom end failures account for almost all of the CP4 problems they see.

[@tmccourt22]

Do you guys have CP3 conversion kits that don’t require altering emissions or tuning? Only reason is because I have emissions testing where I am.

[@Veikra]

there are CARB california approved kits advailable for many vehicule. It only needs to be reprogrammed because the flow rate of the pump is different. If it's good enough for california it's good anywhere. The truck will work just the same

[@jimclark4489]

Check with S&S. They offer a CARB compliant CP3 conversion kit option that does not require tuning.

[@stevezickefoose8563]

Does the 2019 Dodge Rams 6.7 have the same cp4 pump

[@germanvargas4253]

Steve Zickefoose yes

[@MF-Roided]

So if I do a lift pump, does that save it completely? Also, if I do a lift pump and eventually do a cp3 conversion, can I keep that same pump or is it now useless? I’m trying not to go deeeeep into money here

[@lucaserickson318]

If you add a lift pump it will not stop the cp4 from destroying itself, I think water is what is killing these pumps and a lift pump will provide better protection compared to the stock filter. I ran a year with a airdog plumbed backwards due to the incorrect diagram in the instructions and I didn't have a cp4 failure. If you do a cp3 conversion your cp4 is pretty much worthless but the lift pump will work perfectly fine with a cp3, but you will want to use compressed air on the injector return line to provide 80 psi of backpressure to start the truck faster if it will not start, it took me about 5 minutes of cranking to get it to start after the swap. You will be looking at 1400 dollars minimum to do the swap if you don't use a used pump, depending on which pump and tuning it requires.

[@jacobgrimm7071]

About to go start working on my 2012 2500. I'm pretty sure my cp4 blew up yesterday.

[@raptureready9502]

Sorry to hear

[@kyleandersen6492]

Im sorry dude

[@dpdevil1]

How many miles

[@jacobgrimm7071]

@@dpdevil1 right around 80k. I made the mistake of deleting and tuning the truck without installing a lift pump so it was my fault. Expensive lesson to learn haha

[@jasonjackson329]

@@jacobgrimm7071 how can you tell it blew up ? And is it pretty a guarantee once it blows up that you’d injectors are trashed and stuck spending $$$$$ or is there some hope

[@orlandoduran7740]

thats the cp4.2 you got there too

[@jamespollock9772]

Will a lift pump prevent the cp4 from failing altogether?. I’ve had a lift pump from 50000 miles. I have 98000 now and I’m starting to really research this failure I keep hearing about.

[@Blue_Collar_Hunter]

I would like to know the same info. Please pass it on if you find out. Thanks.

[@miasmaro98]

It's a good preventative but not a 100% guarantee it won't fail

[@jamespollock9772]

@@miasmaro98 thank you sir

[@tobysmarts]

Lift pump will not prevent cp4 failures. I recently experienced this issue. It totally sucks.

[@logancooper2326]

Will an air dog 160 lift pump save and help this pump stay alive longer

[@EpicRebel12]

Just helps do a cp3 when possible. I changed my cp4 out at 110k miles and I didn’t have any metal though.

[@logancooper2326]

@@EpicRebel12 how much did it cost

[@aksleder907]

Ford runs the same cp4 on the 6.7 with a lift pump that operates at 60 psi and the cp4 still fails. So your solution isn’t really the solution. From what I’ve seen keep up with your filters, run quality fuel, fuel treatment, keep an eye on rail pressure and hope for the best

[@miasmaro98]

Ford just has an in line pump not an actual aftermarket lift pump like a FASS or Air Dog

[@skylinezz4482]

So basically just have to be lucky it doesnt fail when ur even taking care of it like that

[@jonnis240]

Bosch Cp4.2 is that 2 piston pump. Cp4.1 is the one piston pump.

[@jamesschneider6136]

How many miles?

[@deleteduser3749]

My 328d has a cp4. Died without notice at 131,000 miles. Car was getting 50mpg on the open highway two weeks prior.

[@jamesschneider6136]

@@deleteduser3749 sorry to hear that...

[@deleteduser3749]

@@jamesschneider6136 me too. I am becoming an expert on my fuel system and am going to fix it myself. Then I'm pulling off the bmw badges.

[@jamesschneider6136]

@@deleteduser3749 Hope it all works out for you! Haha Break My Wallet! Had a BMW M5 and it cost me $6k in repairs so when the oil pump failed I did donuts in it until the engine blew up

[@TheNiekerk]

Adding fully synthetic 2-stroke oil to diesel fuel to extend CP pump and injector life?

[@malazkm]

Can i put a cp3 pump im my gmc dually

[@mattbrown7566]

malazkm 2010 absolutely! Check out Wehrli Custom Fab for a conversion kit. There are others also but WcFab has a great line of products.

[@stevewaclo167]

Not if the 2SO has zinc, which builds up on injector nozzles, wrecks the spray pattern and can prevent injector shut off. So many people recommend 2SO, but it can be trouble.

[@montana1636]

Fully synthetic (Husqvarna premium) etc

[@Garth2011]

Word is the low sulfer diesel in the USA is not lubricating as well as the old formula diesel.

[@Veikra]

and yet they make a pump that is a total engineering facepalm.

[@Veikra]

Check my videos, it's not a lift pump matter, the design is flawed. I made a side by side comparision of cp3 and cp4 , highlighting MANY flaws of the cp4 vs cp3. That pump is no good and need to be replaced by a cp3 in all vehicules before it kills the whole injection system.

[@Foxfried]

A LIFT PUMP will not magically add lubrication to your fuel. Best option is to run a fuel additive to increase lubrication and get your scoring to match regular sulfur diesel.

[@Blue_Collar_Hunter]

Any recommendations?

[@Foxfried]

@@Blue_Collar_Hunter OptilubeXL has the best results if using with pump diesel. Or you can use BIO diesel direct from pump with no additives.

[@Blue_Collar_Hunter]

@@Foxfried thanks, I'll look into the Optilube XL. I have no interest in running bio diesel. I do have a Fass lift pump & currently waiting for my Exergy system saver to be delivered. But if & when my Cp4 fails I will convert it to a Cp3.

[@xaploq1]

So allegedly there is a lawsuit against chevy and duramax because the U.S. fuel does not provide enough lubrication.

[@shanevincent2641]

We will never see a dollar

[@davidperry4013]

They should sue bosch for making an inferior car part.

[@USMCRON]

Bosch made the CP4 pump for European standard diesel fuel which is not to the ridiculous overkill of the US standardized low sulphur content and therefore less lubrication. The design is flawed in this matter by “cheapening” the way the cam and lobe interoperates within the pump versus the CP3.

[@jeffs2809]

@@USMCRON this is not true, US is 15ppm, EU is 10ppm.

[@pvcarmon1]

How in the F isn't there a class action against Bosch for creating that POS. I truly feel sorry for Duramax owners, seems like every one of them I know without toons has had a CP4 failure, one in particular with less than 20k miles. Another friend tried to buy a CP3 upgrade and nobody would ship to California. I would not expect 70K miles out of one of those POS. Stay local, be careful taking long trips regardless your mileage.

[@Spahi77]

Its not Bosch fault. These things run in Europe without a problem. The problem is our piss poor diesel does not have the lubricity that our European counterparts do, and it eventually scars the pump till failure. This is why cp4 owners need to run additives like Optilube XPD in every tank. Exergy has a new metering inlet with double mesh screens to prevent a CP4 grenading. Its called a CP4 saver. This combined with a lift pump should help the CP4. Personally after knowing this, i blame US automakers for using the Bosch system and upgrading to the CP4 and should have stayed with the CP3.

[@jeremybroderick9465]

gm quit using bosh cp4, switched to denso fuel system in 2017, ford and dodge still use the bosh cp4

[@six159]

There are several class actions.

[@six159]

Ford uses the seimans now

[@MrTheHillfolk]

He needs to send it to a friend in another state , and have his friend ship it to him. Thats how my cousin got a 49 state cat for his car, which is half price of the 50 state version.

[@MrMallen1315]

really wish I could hear you..... audio is very low. FYI

[@Jagshemasher]

Turn your volume up - the audio is fine

[@davidperry4013]

My 2015 Camry which as gas engine so, I do not have to deal with this bullshit CP4 disaster. The fuel pump is justed a brushed dc motor with an impeller inside the fuel tank that sends fuel to the FPR than the fuel rail and tuned port injectors. If the fuel pump shits in a gas engine, it's only a 125 dollars quality Japan or US made part for a Toyota. Pretty much the only way to kill an electric fuel pump for a gasoline vehicle is you have to be dumb by running it on 0 miles to empty too many times.

[@fuqutube]

So tired of my Chevy Duramax issues. NOTHING BUT PROBLEMS! F#@K DMAX

[@antn8387]

thats the poo poo Bosch pump

[@HumpDaddy01]

Why it needs a lift pump? Easy. It's a POS!

[@ChrisSmith-ig9jq]

no its not a lift pump issue! Design issue, lubricity issue, water in fuel issue, running on low fuel and picking more trash up and lack of changing filters all play a part in ruining the poor design of the CP4 junk

[@mikeparrish9364]

Anyone who has had a fuel pump failure in a Chevrolet diesel should go to www.hbsslaw.com to join a class action lawsuit for free to get Chevy to own up to the problem.