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so let me just ask this question to see where most true mechanics or people with true knowledge of the Duramax engine.


QUESTION:
if your CP3 is going out because of whatever reason, and you think you have pretty good knowledge on how engines are built, to be taken apart and rebuilt, would you do the CP3 replacement yourself or would you just pony over the money and have a shop do it for you?
 

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so let me just ask this question to see where most true mechanics or people with true knowledge of the Duramax engine.
QUESTION: if your CP3 is going out because of whatever reason, and you think you have pretty good knowledge on how engines are built, to be taken apart and rebuilt, would you do the CP3 replacement yourself or would you just pony over the money and have a shop do it for you?
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Wed 14 Ayg '19 @ approx. 4:30 PM MST

One look at the multi page instruction sheet from S & S Diesel made it clear to me I made the right decision - turned the job over to a qualified shop.

May I assume you made a typo error, and meant to ask "if your CP 4 is going out".

That's the problem - from what you will see about CP4 failures there is little or no advance warning.

You are assuming the CP4 is repairable. I get the impression from other threads and posts the thing, once it goes bad, is discarded. (? ? ? )

I worked as a truck mechanic during part of my high school & college years, later worked as a machinist's trainee, maintain my own boats, cars & airplane, so I have at least some degree of familiarity with mechanical devices and tools.

Let me tell you - one look at how far the GM dealer had to take that complex piece of machinery apart, and I KNOW I did the right thing! In addition to all the mechanical work, there's all those connectors of various types you either understand how to disconnect and then reconnect..or break....! Maybe you can find and hire that guy in here who claims it is a 6 hour job?
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sent while hiding in the "fitting room" of the local Fredericks womenswear store...….

 

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so let me just ask this question to see where most true mechanics or people with true knowledge of the Duramax engine.


QUESTION:
if your CP3 is going out because of whatever reason, and you think you have pretty good knowledge on how engines are built, to be taken apart and rebuilt, would you do the CP3 replacement yourself or would you just pony over the money and have a shop do it for you?
i would personally pay to have it done for 2 reasons. First, while i have the tools, and skills to do the work, i am not an expert, i have limited free time, and that is kind of a large time commitment. Second, it would take very little contamination to brick the injectors. The though of "was i clean enough during the install" would be in the back of my mind until i sold the truck of the pump failed.
 

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If your truck is 2018, you probably have a CP4, if you think it's going bad, it's probably time to convert TO a CP3...
 

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My CP3 wasn't going out but I screwed up a return line while replacing the injectors last time and ran out of weekend to fool with it. So I had it towed to the dealer on Monday and while they were fixing that I also had them replace the CP3 simply because they were already in there, the truck had 365,000 miles on it and I really didn't want to fool with it. It wasn't cheap plus I was in a rental p/u the whole time it was in the shop. I think rental fees were about $1800 alone.
 

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I would do it my self but then I'm retired and have been a mechanic all of my life. I have a shop with a lift and tens of thousands in tools.

There is nothing about this job that a talented amateur can't handle. It is complicated but that is why cell phones have cameras, isn't it?

However, I can easily see why people would be reluctant to tackle this job. Only you can decide whether your time is worth more or the shop cost is worth more.
 

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I would do it my self but then I'm retired and have been a mechanic all of my life. I have a shop with a lift and tens of thousands in tools. There is nothing about this job that a talented amateur can't handle. It is complicated but that is why cell phones have cameras, isn't it?However, I can easily see why people would be reluctant to tackle this job. Only you can decide whether your time is worth more or the shop cost is worth more.
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True - we old "wrench-turners" can do fine with "bolts and nuts" jobs. Welcome to the computer age - there are all kinds of propriatory connectors that can be easily broken if you don't know the secret. That and a bad back decided the issue for me.
 

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You know, once you have taken a connector apart a few times it seems pretty obvious how to do it but the first time can be a real head scratcher. When I come across these new and, for some unknowable reason, essential connectors I try to find a similar one that is easy to get to so that I can have a good look at it. That isn't always possible though.

Now the back thing can be a decider on it's own. Gone are the days when you could open the hood, climb inside and get to just about any part of an engine while sitting on it or on the radiator.

One thing I like about having a lift is that I can take the tires off and set the truck down low enough that I can get into it. I don't think that will work with the 2020s though. I hate having to use a step to work on the engine. I'm too old and fat for stepping up 18" 200 times a day.
 

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Having just recently replaced my CP3 myself I would still do it myself if I had to do it again. It took WAY longer than I had read it would but that is usually the case when I am wrenching. If I had to do it again I am sure it would be considerably faster. There are a lot of tips and tricks that I learned but can't think of right now to write here. Except don't take off the horn - that was bad rabbit hole.
 

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Discussion Starter #13
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One look at the multi page instruction sheet from S & S Diesel made it clear to me I made the right decision - turned the job over to a qualified shop.

May I assume you made a typo error, and meant to ask "if your CP 4 is going out".

That's the problem - from what you will see about CP4 failures there is little or no advance warning.

You are assuming the CP4 is repairable. I get the impression from other threads and posts the thing, once it goes bad, is discarded. (? ? ? )

I worked as a truck mechanic during part of my high school & college years, later worked as a machinist's trainee, maintain my own boats, cars & airplane, so I have at least some degree of familiarity with mechanical devices and tools.

Let me tell you - one look at how far the GM dealer had to take that complex piece of machinery apart, and I KNOW I did the right thing! In addition to all the mechanical work, there's all those connectors of various types you either understand how to disconnect and then reconnect..or break....! Maybe you can find and hire that guy in here who claims it is a 6 hour job?
- - - - - - - - - - - - - - - - - - - - - -
i would personally pay to have it done for 2 reasons. First, while i have the tools, and skills to do the work, i am not an expert, i have limited free time, and that is kind of a large time commitment. Second, it would take very little contamination to brick the injectors. The though of "was i clean enough during the install" would be in the back of my mind until i sold the truck of the pump failed.
If your truck is 2018, you probably have a CP4, if you think it's going bad, it's probably time to convert TO a CP3...
Im assuming hes asking about a different truck, if it were an 18 id hope the dealer would take care of that.
thank you for the answers.

just to clarify:
1. I was asking about another truck
2. I am aware that there is a difference between cp3 (2001-2010) / cp4 (2011-2016)
3. I was an owner of a 2006 LBZ that had over 200K on it when I traded it for the 2018
 
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