Duramax LML CP4 fuel pump failure

[80Ram]

As a owner of a 2016 GMC Sierra 2500 HD Duramax I'm concerned about the CP4 fuel pump giving me problems down the road. Right now I have about 53,000 miles on my truck and I have been well pleased. It seems the 2011-2016 models have the CP4 fuel pump which could cause potential catastrophic damage to the trucks fuel system. This would be very costly to say the least. Has anyone experience CP4 failure or could this be blown out of porportion for aftermarket parts?

[CBWELL]

I have a 2012 LML and have a FASS fuel system installed. I am told that it will help prevent the CP4 failure. I gives the fuel system 3 filters and provides pressure to the CP4 allowing the CP4 to supply the injectors only. Google Fass Fuel systems to see their products. Another good information is the website Diesel Place!! I am very happy with my system and have almost 250,000 kms on the engine. I change all fuel filters at 20k, or every second oil change. I use Rotella T6 synthetic oil.

[wulfraat]

Sounds like a reason to upgrade to the L5P with HP4 pump

I wouldn’t sweat it. Don’t put crappy fuel in and keep the tank at 1/4 full good to go.

[CBWELL]

I also use a fuel conditioner/lubricant every fuel fill. Have had good luck with Stanadyne and Schaeffer's diesel addatives. Buying good fresh fuel is very important, and I try to go to truck stops to get the most current blends, especially in the fall and winter.

[SteveSueMac]

I am just hearing about this for the first time. Found this TSB online:

https://static.nhtsa.gov/odi/tsbs/20...44240-3551.pdf

I’m not sure of the frequency of this failure but apparently when it happens it’s catastrophic and a 5-figure repair bill!

I sent the TSB to my dealer where I’ve had all my service done on my 2013 Duramax to ask if they ever examined mine for this problem.

I will not worry. I will not worry. I will not worry. [emoji3]

As for the Stanadyne - there are many flavors - what do those who use it recommend - just the pure “lubricity” formula or something else? Amazon has a 64oz jug of that for $32 and says it’s good for 500 gallons or about 14 fillups with my tank. That’s less than the cost of a gallon of diesel per fill up - sounds like cheap insurance to me....

[prostar]

I have a 2007 duramax and got an engine code that shut down the engine. I called the dealer and he told me to try and start after a couple of minutes. That worked and I went to dealer next day where they put new fuel filter on. He thought maybe I got dirty fuel since I change my fuel filter every 10,000 miles. I am looking to put the Fass lift pump on my truck also. I only have 120,000 on the truck so I want to keep it a while longer. I have always used Stanadine in the fuel.

[CBWELL]

I use the lubricity formula as well as the winter formula. I prefer the Schaeffers, but it is almost impossible to purchase in Canada. I try to stock up when in the US. I like the Diesel Treat Premium, both winter and summer. Another Schaeffer product that I have on hand at all times is Penetro 90. It is the best penetrating oil I have ever used. I worked in the fire service for many years and it was one of the only products that made rusted bolts removeable. Friends in the auto body industry also swear by it.

[GMFL]

I have a 2016 LML and had the CP4 pump fail at 7000 miles so fixed under warranty 9800.00 was repair cost. New pump, fuel rail, injectors, the works. I made GM agree to cover the problem for a additional 100000 miles. They paid for GM platinum protection plan for up to 120K miles. I feel safe with that in place.

[Tater]

I had a 2015 LML and traded at 80,000 miles with no issues other than a loose fuel pump connection about 4,000 miles in. The only reason I traded was because I had the extended cab and wanted the crew cab and camera capability. Both were and are 2WD although I don't believe that would make any difference whatsoever.

[Mhphhoward]

Originally Posted by 80Ram

As a owner of a 2016 GMC Sierra 2500 HD Duramax I'm concerned about the CP4 fuel pump giving me problems down the road. Right now I have about 53,000 miles on my truck and I have been well pleased. It seems the 2011-2016 models have the CP4 fuel pump which could cause potential catastrophic damage to the trucks fuel system. This would be very costly to say the least. Has anyone experience CP4 failure or could this be blown out of porportion for aftermarket parts?

No. Had an '05, now a '12, many many miles (ME to AK 14 times rt) and no fuel pump failure.

[Mhphhoward]

I wouldn't modify a Duramax in any way. Did it.... bad news.

[guskmg]

LMM '07.5 here. I have added a FASS fuel pump/filter system and a delete kit for unlimited Bio use. So far 130,000 mi. and no trouble. I did add the OEM fuel filter delete kit since it is downstream of the finer FASS filter system. It retains the water in fuel warning. I use no lubricity additives, but probably will in the future.
guskmg

[Life is a Highway]

Thanks for that information, Good that you got them to cover it again for 100,000 I am sweating the same with our new F-250 SuperDuty. I do use AMSOIL injector Clean and Cetane boost. Change Filters every 10,000 miles.

[cliffcharb]

Don't sweat it, its mostly hype with lawyers driving the cause. Most American manufacturers used the same pump. Do some fail, yes, but all components fail at some point or another. I know many with Ford super duty fleets and no issues. My father in law had one go out in his F450 (under warranty), but his daily F350 with 150k miles no issue. In my fleet we've had zero issues