CP4 weak point and why the CP3 is the only solution.

[@californiajeeping]

In the video above it is clear why the cp4.2 is an inferior design to the cp3.

The ramp rate on the shaft/cam is radical and the friction is very high. Remember its not lubricated by oil but by diesel. This is why additives are so important. I have been running 2oz of hot shots EDT and I frequently fill with renewable diesel all with hopes to stave off the eventual nuclear destruction of the fuel pump.

The CP3 has a much much much better design with more surface area for wear and higher flow volume. It does not have the metal to metal ramp that causes wear on the cp4. There is no roller bearing either. If the ramp rate was lower on the cam for the fuel pump lifters they could have run a flat lifter with no bearing which is likely how it was designed. At some point Bosch likely needed higher pressure so they added a ramp and then a roller to the lifter to reduce friction. This is speculative.

If we get a CP4 recall will the fix from Bosch be to retrofit to a cp3 or will they simply find a way to pin or hold the cp4 lifters from rotating 90 degrees? In all honesty that would not be a bad fix. Replace the pump with a new one with 2 plastic keepers and a flat spot on pump lifters. Similar to how some v8 engines have a plastic keeper on a lifter to keep it from rotating. Thats all the pumps need to not explode.

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[XJFanatic]

Just throwing this out there the CP3 ain’t that great either. My 3rd Gen Cummins was on its 3rd when I traded it and at $1200 a pop. They don’t fail outright normally but tend to just start leaking diesel when they get cold.

 

[rharr]

There are a few bypass type kits that mod the CP4 to change how the diesel flows and prevents chunks from entering the fuel rail. Same guys who's video you posted.

https://www.drivingline.com/articles/new-product-spotlight-ss-diesel-motorsport-s-cp42-bypass-kit/

Maybe one of you EcoD Indiana Boys can stop by and talk to these folks.

 

[IOS-XR]

When I took my diesel Glad in for service last month I asked the service manager about the pump recall situation. He said they’ve been doing the older Jeeps and he said he’s heard down the grapevine that the gen 3 engines will be recalled in ‘23. He said what they are being told to do is retrofit the CP3.

 

[Rusty PW]

Be great if they did install the CP3 pump in the recall.

 

[LordEnzo]

Still waiting to order a diesel glad, probably a '24 since my lease is up Nov '23. This and the overheating are the only concerns I have right now. If they get it ironed out, I can figure out an aftermarket approach for cooling, which a couple other threads seem to be working out as well. Otherwise, I'll chance the 4xe and possible mid cycle refresh expected for '24.

 

[@californiajeeping]

Be great if they did install the CP3 pump in the recall.

CP3 is capable of 550-600HP according to some.

That is significant compared to our little cp4 that cant do 250 without exploding.

 

[@californiajeeping]

There are a few bypass type kits that mod the CP4 to change how the diesel flows and prevents chunks from entering the fuel rail. Same guys who's video you posted.

https://www.drivingline.com/articles/new-product-spotlight-ss-diesel-motorsport-s-cp42-bypass-kit/

Maybe one of you EcoD Indiana Boys can stop by and talk to these folks.

Still when it destructs your dead in the water. This just saves the rails and injectors.

 

[Almost]

Still when it destructs your dead in the water. This just saves the rails and injectors.

Yeah, but that is a significant cost especially out of pocket after the warranty period. I would rather just replace a pump for about $1K vs also having to buy about $3K worth of injectors and fuel rails on top of it.

 

[Rusty PW]

CP3 is capable of 550-600HP according to some.

That is significant compared to our little cp4 that cant do 250 without exploding.

What I read the CP3 is good for just over 600hp. The CP4 tops out just bottom 500hp on the bigger diesels.

 

[woffman5]

What I read the CP3 is good for just over 600hp. The CP4 tops out just bottom 500hp on the bigger diesels.

There are two different models, the CP-4.1 and CP-4.2. The 4.2 has two pumping elements and, as a result, higher fuel flow rate to support the larger diesel engines. The 4.1 is a single element, so lower flow rates to support the smaller motors. The Cummins recall for the 2021/2022 model year (at least I think that the model years) is a result of failures associated with "overdriving" the pump to support higher HP/torque outputs and a substantial increase in fuel pump failures. Ours is coming, it's just a matter of time. The relatively low number of failures in the Gen 3 EcoDiesel population isn't a priority right now. It's cheaper for Stellantis to pay for fixing the few (relative) failures that occur in the Gen 3s right now than try to fast track a recall and source parts. I trust the new one in mine about as far as I can throw the truck (spoiler alert, I'm 5' 10", 165 lbs, and can't lift up the truck), so for now, the tow strap is in it at all times, and the rescue rig (wife's 4xe JLU) is always nearby, or a phone call away. While the 4xe's have issues, ours has 17k on it and no major issues. We did manage to rattle several fuses loose (we air down now, I'm stubborn, what can I say!), and had tons of issues with CELs in the beginning (who designs a gas cap that only goes in one way, are you fricken kidding me), but the 4xe has been super reliable. Most importantly, it didn't strand me on a trail in the mountains.

 

[rharr]

so is the ecoD a CP 4.1 or CP 4.2?

 

[@californiajeeping]

from a ram forum regarding the 4.2:

" 1) The CP4.2 injection pump was installed in all 2019-2020 RAM 6.7s. The original had an asymmetrical cam design for the lifter. The theory of failure is that the aggressive ramp rate of the cam lobe contributes to the lifter turning in the bore, effectively kicking the roller off it's intended path, causing it to grind and send metal shavings through the system. Additive companies claim to aid the prevention of this by increasing the lubricity in the fuel, making it "slippery" so the lifter roller doesn't stick and kick to the side. Around early September, a revision to the pump was released [Pump Identification Link]. It is identified by the large machined dimple in the top right corner. All other small dimples on any of the pumps are nothing but date/mfg coding and do not indicate design differences. The revised pump has a symmetrical cam lobe theorized to lessen the ramp rate of the lifter, reducing the chance of the lifter spinning in the bore. "

Someone take a look at their pump if its 2 dimples its a 4.2?

 

[@californiajeeping]

I believe we have a 4.2. There are apparently 2 "revisions" or more of the 4.2 design. No clue how to tell what they changed or how its better but if ram is putting cp3's back in then none of them are any good.

 

[Zybane]

Does the engine need to come out to replace this pump? If not, how much stuff needs to get removed in order to get to it?

Dealerships do terrible work and barely put stuff back where it was, so curious how much stuff I'd have to double check if they put a CP3 in mine.

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