Truck just died at the lights. Had to tow it to garage, Waiting to hear from them. It made a couple skips just before dying. 93K miles 2011 GMC Duramax. It sounds like no fuel? Ive been watching youtube videos and fuel pump replacement seems like a nightmare. Replace injectors, rails, drain fuel tank along with pump. Is this right. 2011 would be LML right? with CP5 fuel pump? If this is the case what would a job like this cost? Is there any chance it could be something else that just causes the diesel to quit?
OK, I had my filter head lose its prime over the winter so I changed it and seemed to solve that problem. It seemed like same issue today when it died so I'm thinking fuel problem? Will the TCM cause it to quit like that? It has at least 1/2 tank. I just did full brake job yesterday.
I tried pumping up the primer and it was soft so I pumped it until it was firm ran back around and tried to start, still nothing. Tried priming again and it was soft so I pumped it till it firmed up and tried again, still nothing.
Before it died I felt a couple skips as I pulled up to light then it just quit. Before that it was running good. I didn't get any messages prior. Im really bummed about the CP4 pump issues. This is the first brand new vehicle I ever bought thinking it was good for around 300K. I feel even if it isn't the pump I need to get rid of it before it ends up a real problem....which it already is, I just can't trust the truck it seems.
There is the option to convert it back to the reliable CP3 pump, if that's what it turns out to be.
And there's the Exergy System saver if sticking with the CP4...has a smaller mesh screen to catch the debris when/if it fails....doesn't stop it from failing, just tries to control the damage elsewhere.
Dealer is gonna hopefully look at it tomorrow and give me the verdict. What if no codes?
What % of these pumps fail you think?
A conversion to CP3 pump still sounds like a big job?
Horns is right that you are ahead of the curve in coming for advise now. You need to have a little diagnosis first, including codes. Lincoln Diesel Specialties has a reasonably priced kit that has everything you need to make it good again and more reliable if it is the CP4.
Nobody could fault you for wanting to do the conversion to the CP3 regardless of the outcome of your diagnosis but there are a lot of trucks running around out there with lots of miles on their CP4 and still going strong. The main problem with the CP4 isn't that it is total junk. It does work for most people. The problem is that when it does die it takes the whole fuel system along with it.
There are a lot more people who need a new filter head than there are people who need a new CP4. Think happy thoughts for now and see what the mechanic says.
For what it is worth, a lift pump will prevent air leaks that leave you stranded.
Thx for the input. What exactly is a lift pump? Is it a replacement or addition?
I did just replace filter head within the last yr maybe its a bad one?
Just pulled my cp4 with 150k miles on the truck. Seems like it had been done before as there where some new lines and stuff on the truck. So it probabaly has less miles than that. I bought the truck at 60k so must have failed before I purchased. Pulled reg and screen was clear as could be. Like mention Lincoln diesel has a severely discounted kit to replace the cp4 or can get the same kit with a cp3. Iirc its around 2100 for the one with cp4 and depending on cp4 2300 and up. I wouldnt have the dealer do the work or supply parts as they will screw you bad. Find a good diesel performance shop to do the work if you cant and get the parts yourself from Lincoln. The job isnt terrible just time consuming.
Let's say 2200 for the parts kit, and 2-3500 to tear down and reinstall at a good diesel shop. Probabaly books for 30 or so hours but could be done in 15 or so. All depends on if you're deleting at the same time or re installing all the egr stuff, sticking another cp4 in or swapping to cp3. The dealer it would be anywhere from 8k to 15k.
A lift pump is a low pressure pump that mounts back near the gas tank. It has two main functions. The first is that it keeps a little pressure on the system so that any leak is a fuel leak, not an air leak. A fuel leak is not a good thing but it doesn't leave you at the side of the road waiting for a tow truck. The second thing a lift pump can do for you is to allow you to install better filters for the fuel so that what the CP sees is extra clean. You can install filters without a lift pump but then the CP has to suck harder on the fuel inlet which can lead to more air infiltration or even cavitation.
Installing a lift pump is a good thing that isn't essential but lots of us think it is worth while. It is the same sort of thing as changing out the CP before it fails. You don't have to do it but nobody is going to call you an idiot for doing it. Just don't get carried away with the fuel delivery ratings of some lift pumps. 50 GPH is all you can use on a street truck. The big pumps are just big. It's like having a 12 incher. It might give you something to brag about but otherwise it isn't of much use.
The first lift pump I ever did lasted about a week and then came back. Since I didn't consider myself an expert on the subject I sent my customer to another shop that specializes in diesel pickups. They had the tools to diagnose it properly. Their diagnosis said that the lift pump had failed again. They replaced it and the pump was warrantied. I didn't do anything wrong. The reman pump I used was defective. I just didn't have the confidence yet to continue on. Now I do.
This job takes a lot of time and patience but there are no big road blocks. There's just a lot of stuff in the way. I'd do it again without hesitation.
Also Lincoln diesel has the best priced kit and their customer service is great. Fwiw I wouldnt stick a cp4 back in unless you live somewhere you cant delete. Their are options for cp3 swaps without tuning though also. I just checked Lincolns site it is slightly higher than I quoted
I agree with these guys. If you dont have to stick with the CP4 and can do the CP3 conversion i would go that route since its proven to be a better design and more reliable than the CP4. If you have to replace the CP4, Injectors direct has a kit you can get that is very reasonably priced. I just pulled my CP4 to do a 10mm CP3 stroker. The CP4 only has 23k miles on it if your interested i can help you out with the pump and you can install the Exergy screen onto it and be on your way. I would definitely get a Fass or Air Dog lift pump to help the high pressure pump out. Personally i had a Fass and Air dog on my trucks and will run Air Dog as it was much quieter than the Fass.
A lot of good info and advice gents, thx.
If it turns out to be the filter head again I'll just fix it but then I feel like I'll just be waiting for the pump to go? Im not really looking to spend 2-3k on something that might break? Would you guys just bite the bullet or trade in/sell truck? Its piece of mind and dependability that I desire. Is the pump an "if" or "when" it fails?
2011-2015 is a lot of trucks (CP4s) that are still out there racking up the miles?
Its piece of mind and dependability that I desire. Is the pump an "if" or "when" it fails?
2011-2015 is a lot of trucks (CP4s) that are still out there racking up the miles?
If anyone knows of a mechanical device of any sort that will never fail I'd like to know about it. An anvil will fail eventually.
The CP4 will fail. It's replacement will fail. That replacement will fail. The question isn't whether something will fail but whether it will outlast the other parts of the truck or whether it will be a maintenance item before that. An original CP3 will probably make it to the scrap yard in working condition. A CP4 might make it there too but the odds aren't as good.
I would prefer a CP4 to a 6.0 power stroke any day. In fact to any Power Stroke. If you want the most reliable engine possible get a Dodge (not Ram) 12 valve with a P-pump. It will outlast everything else on the truck several times over. But then you will have to deal with rebuilding the trans often, the dash cracking to bits, the body turning to rust etc.
You could get a Peterbilt and it would probably make it to two million miles but at 7 mpg. There just isn't a perfect answer. Or maybe there is. Put a Cummins engine on an Allison transmission and mount it in a Ford body. Nah, you couldn't get any to work on it and who knows where you would go for parts.
2016 too. It's a roll of the dice as to if or when. Some drop @ less than 30k miles under warranty, others have over 200k miles with no failure.
Clues point to our U.S. fuel with it's lower lubricity rating vs EU fuel that the pump was designed to run on.
CA fuel is the same as EU, and the same built trucks running their fuel in the great white north don't have issues.
If it's not your pump, for peace of mind, start using a quality fuel additive to improve lubricity. Adding an aux FWS filter and a small lift pump, for extra water in fuel protection is another idea.
Look into installing the 'system saver' on your pump (although, we're still waiting to see 'if' it works, from someone who has installed one, and then had their pump fail....AND then took the time to report/post on it).
Trade for a '17+ model?....the Denso CH4 that GM switched to, hasn't had the same record as the Bosch CP4.
Just got the call. Fuel pump has failed and they are trying to determine if electrical or mechanical. If they find its mechanical and metal in system then worse case is realized, if not then its an r&r Either way it will need to be replaced. I spoke to him about replacing and they would just replace with another CP4. I could upgrade pump he said but I would have to source it because they would just do GM replacement.
This SUCKS!
If you swap a cp3 in it in my opinion the lmls are the most reliable dmax platform. Either way your cheapest way out is getting it away from the dealer and into a private shop or performance shop and buying the parts yourself from lds. That have a sale going on right now for that exact kit.
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