Chevy Silverado and GMC Sierra Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter · #1 ·
I have a 2016 Sierra 2500HD Denali and recently I had my truck in for a new fuel filter. I drove it for a while and the warning popped up to replace. I had it replaced and then I looked back at my records and it had only been a few thousand miles so I called the dealer and they said to watch the display and see if the life goes down quickly. If it does they said I have an issue with the fuel system. I checked it a week ago and it was at 95% and today the warning message popped up and the life was at zero.

Anyone had this issue?

Jeff
 

·
Registered
2021 GMC Sierra 2500HD AT4
Joined
·
3,479 Posts
Has it been cold outside when this happens? I had this happen with my LML. I'm pretty sure it was due to the fuel in the filter beginning to gel at cold temperature and causing more restriction.
 

·
Super Moderator
2015 High Country Duramax
Joined
·
18,610 Posts
Your probably dropping rail pressure.

Before you drive it much more, or at all, I'd definitely recommend pulling your fuel pressure regulator out of the pump and checking it for signs of metal.

It is pretty easy to get at. It is two torx screws and the one electrical connector. Make sure no dirt and debris fall in there. Look at the screen and make sure there is no metal stuck to, or around the screen.

The CP4 pump is known to shred itself and the very early stages are the issue you describe. The pump starts to fail, and can't meet the desired rail pressure, which will trigger the change fuel filter message.

Other things that can cause this besides the pump, is a restricted fuel filter (obviously), fuel feed line restriction, or a failing/failed relief valve. Also if your tuned, running too big of a tune without a lift pump can drain the rails.

But I would definitely check for metal on the regulator first. If by chance there is metal, hopefully you caught it early enough before it wrecked the rest of the fuel system.
 

·
Super Moderator
2015 High Country Duramax
Joined
·
18,610 Posts
If your still have powertrain warranty left, it would be covered. But if the warranty is expired, they don't have special coverage for the fuel system like the do the emissions system.

Here is an example of a failed pump. This one took out everything. But don't get too far ahead. If there isn't any metal on the regulator, then you may be fine for now. That alone doesn't rule out a pump issue, but it rules out a pump failure at the moment.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #7 ·
The dealer called today and said they are replacing the whole fuel system and will need the truck for another 5 days. It's still under warranty so the 10 k or more repair will be covered. They also noticed a broken weld on the down pipe that was leaking so it'll get replaced too.

After this I assume it'll be like a new truck. I hope it helps with mileage. Would it be smart for me to put a FASS filter system on after this or something similar? I was thinking about trading it in but now I think I'll wait a while.

Jeff
 

·
Super Moderator
2015 High Country Duramax
Joined
·
18,610 Posts
Good to hear it's still warranty.

A lift pump can definitely help. It will help keep the fuel clean and free from air and water. Debris and water are the absolute killers of the cp4 pumps.

A good fuel additive is also a great idea. Optilube xpd is what I use. But most of the top tier products will do you just fine.

The best way is to ditch the cp4 all together and go cp3. Bur warranty obviously won't pay for that.
 
1 - 9 of 9 Posts
Top