2019-20 RAM Cummins CP4 recall announced

[ajg617]

I am impressed with Ram. They are stepping up way more than Ford, which continues to deny the issue, and even GM, who was much more helpfull to customers having the issue, before finally dumping the CP4.
If Ram continues in this direction, I think a Ram will be my next truck.

This sort of support after the sale means a LOT to me.

I think Cummins had a lot to do with that decision since their name was on the affected engines.

[huntindog]

I think Cummins had a lot to do with that decision since their name was on the affected engines.

Possibly.
But the bottom line is the end result for the customer is favorable.... And that is what counts.

[Wileykid]

I think RAM is only doing the recall due to NHTSA starting an investigation several months ago. RAM has been stringing everyone along for two years, telling everyone a "service solution is coming", one update on the pump (CP4.2 in the '20), and all of a sudden when NHTSA gets involved, a recall happens.

One of the things that I have been reading, is that RAM is over driving the CP4 by 50% to get the fuel pressure they need, which is a major contributor of the high failure rate. Ford is not over driving the pump, and has less failures, or not enough for NHTSA to do anything.

Looking at the Mopar website, my VIN is already listed as part of the recall.

[huntindog]

I think RAM is only doing the recall due to NHTSA starting an investigation several months ago. RAM has been stringing everyone along for two years, telling everyone a "service solution is coming", one update on the pump (CP4.2 in the '20), and all of a sudden when NHTSA gets involved, a recall happens.

One of the things that I have been reading, is that RAM is over driving the CP4 by 50% to get the fuel pressure they need, which is a major contributor of the high failure rate. Ford is not over driving the pump, and has less failures, or not enough for NHTSA to do anything.

Looking at the Mopar website, my VIN is already listed as part of the recall.

The CP4.2 is not an update. The .2 stands for 2 cylinders. They make a CP4.1 which is a 1 cylinder pump for the smaller motors, and it has the same problems. Most everyome just calls them all CP4s.
As for the overdrive you speak of... This is the first I have read of it.
There is no need to overdrive that pump as it puts out more pressure than the CP 3 it replaced, and is plenty capable without overdriving it.... So I am skeptical on that.

On another note; Reading thru the ram PR, it states an expected failure rate of 4%.... That is right at the same as Ford and GM, when I saw the NHSTA documents on this years ago.

[ajg617]

Looking at the Mopar website, my VIN is already listed as part of the recall.

My VIN is listed now on both the Mopar and NHTSA sites. I really wonder what they are replacing it with.

[ajg617]

The CP4.2 is not an update. The .2 stands for 2 cylinders. They make a CP4.1 which is a 1 cylinder pump for the smaller motors, and it has the same problems. Most everyome just calls them all CP4s.
As for the overdrive you speak of... This is the first I have read of it.
There is no need to overdrive that pump as it puts out more pressure than the CP 3 it replaced, and is plenty capable without overdriving it.... So I am skeptical on that.

2019-2020 RAM Cummins had two versions of the CP4 - Asymetrical cam (early) and Symetrical cam (later). Documented in TSB 18-060-20. Quick way to tell is the size of the drilled dimples on pump - small dimples (various numbers of them) Asymetrical - large dimple Symetrical.

[huntindog]

2019-2020 RAM Cummins had two versions of the CP4 - Asymetrical cam (early) and Symetrical cam (later). Documented in TSB 18-060-20. Quick way to tell is the size of the drilled dimples on pump - small dimples (various numbers of them) Asymetrical - large dimple Symetrical.

I had heard that before. Not sure why that would be an improvement.
But I have seen the CP4.2 mentioned as an updated version on several websites, so that is a internet myth that refuses to die. There may be different versions of the CP4.2 with all of the big 3, but they are all CP4.2s

What version do you have? early or late. This could be a clue as to just how extensive this recall will be.

[ajg617]

they are all CP4.2s

What version do you have? early or late. This could be a clue as to just how extensive this recall will be.

All 4.2s you are correct. But the cam lobe difference requires different PCM flashes so there has to have been some internal changes. I have the early version with the small dimples. TSB attached.
Attachment 37784

[huntindog]

All 4.2s you are correct. But the cam lobe difference requires different PCM flashes so there has to have been some internal changes. I have the early version with the small dimples. TSB attached.
Attachment 37784

I can understand why the PCM flash would need to be changed due to a cam lobe change.... It is similar to putting a bigger/different cam in a gasoline motor. The fuel calibration needs to be changed then.... What makes no sense is to how that would affect reliability of the pump, in a signifignant manner.

[CX500T]

Cam profiles. Ramp speed, surface loading can all change dramatically with different cam profiles.

From a historical standpoint the early diesels (like late 1800s) had overly complicated injection systems that used huge, very high pressure air compressors.

That was the most common failure point then.

Then slightly lower pressure but more precisely controlled mechanical injection became the norm for about 80 years.

Now we are back to a very efficient injection system that has issues due to the extreme pressures.

The circle is complete.

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