6.0L Has No B@lls

[ChevMech]

As the title implies, I'm having the same problem a lot of people with the GM 6.0 liter have: my truck has no power.

 

I've read extensively online, and I've seen where you can add a performance chip or modified exhaust or intake and you will free some horses. I'm thinking this is more a current failure than it is an aftermarket performance upgrade desire. In the past 6 months, I've noticed my 2009 2500 HD has absolutely no power. It is gear hunting at 75 mph at 2000 rpm with no headwind. I know these are big heavy trucks, but how are you supposed to effectively tow with them if they fall on their face under their own weight? About the same time, I noticed there is now a "catch" in the idle while you're waiting at an intersection or drive through. Could the two be related?

 

Not too long ago, I used my company's 16ft enclosed equipment trailer to move a 350lb machine. The truck would not hold a gear, and I could almost literally watch the fuel gauge zip towards the E. Not long after, I began working with another individual that pulls a similar trailer loaded with equipment constantly with an F-150 with an EcoBoost. My first thought is I would have to forfeit eating to pay for fuel if I had to tow that much with my "HD", while they're getting moving right along down the highway with ease in a much lighter duty truck. and getting much better fuel economy. I was forewarned before I bought the truck that 6.0L were fuel hogs, but I at least expected to have the power to justify it.  

 

All of that being said, does anyone have any idea where I should start? I'm not looking to win a pull or race, just be able to use my truck for what it was designed to do. 

[sdeeter19555]

As the title implies, I'm having the same problem a lot of people with the GM 6.0 liter have: my truck has no power.
 
I've read extensively online, and I've seen where you can add a performance chip or modified exhaust or intake and you will free some horses. I'm thinking this is more a current failure than it is an aftermarket performance upgrade desire. In the past 6 months, I've noticed my 2009 2500 HD has absolutely no power. It is gear hunting at 75 mph at 2000 rpm with no headwind. I know these are big heavy trucks, but how are you supposed to effectively tow with them if they fall on their face under their own weight? About the same time, I noticed there is now a "catch" in the idle while you're waiting at an intersection or drive through. Could the two be related?
 
Not too long ago, I used my company's 16ft enclosed equipment trailer to move a 350lb machine. The truck would not hold a gear, and I could almost literally watch the fuel gauge zip towards the E. Not long after, I began working with another individual that pulls a similar trailer loaded with equipment constantly with an F-150 with an EcoBoost. My first thought is I would have to forfeit eating to pay for fuel if I had to tow that much with my "HD", while they're getting moving right along down the highway with ease in a much lighter duty truck. and getting much better fuel economy. I was forewarned before I bought the truck that 6.0L were fuel hogs, but I at least expected to have the power to justify it.  
 
All of that being said, does anyone have any idea where I should start? I'm not looking to win a pull or race, just be able to use my truck for what it was designed to do. 

Without knowing the maintenance, could be anything...

Steve
2012 2500hd

[ChevMech]

1 hour ago, sdeeter19555 said:

Without knowing the maintenance, could be anything...

Steve
2012 2500hd
 

You do bring up a good point. My apologies for omitting that information.

 

The truck has 135k on the clock. Judging by the CarFax and the amount of oil changes it had a different dealerships in different parts of the county, it has primarily highway miles with regular service. Since I've had it, I've followed a similar patter. Back in December of 2015 I installed a set factory replacement AC Delco plugs and wires. They are gapped to spec. Recently, I installed a K&N air filter. Other than a wheel bearing, I have had no major issues with this vehicle.  

 

[Colossus]

find a supercharger to put on it. 

[intheburbs]

You need to start digging into the motor.  Something's wrong.

 

My 2008 Suburban 2500 has 175k miles on it, and the LY6 is still as sprightly as ever.  Just recently I had a buddy in it for the first time, and I did a 0-100 run and she pulled like a freight train all the way up to 100.  He was shocked how fast it was.  Shifts happen right around 5800 RPM.  I deleted the speed governor with the tune and I've had her as high as 120.

 

Have never taken it to a dragstrip, but an unofficial stop watch run 0 to 60 is about 7 seconds flat. 

 

On the towing aspect, last summer we pulled this 8600-lb behemoth (below) out to Yellowstone, climbing as high as Powder River Pass, elevation 9666 feet.  Total loaded weight was just over 16,000 lbs.  I've never felt like the truck is underpowered in the least.  Yes, it gets abysmal gas mileage - 12 mpg around town, maybe 15 on the highway if I behave myself, and about 7 mpg while towing.  Yes, it's not as fast as my Denali, but it'll eat 5.3 trucks and 5.7 hemi trucks for breakfast, lunch and dinner, every day.

[Logan Lanfear]

It seems like this could be fuel related but usually that would throw a code.  Has anything come up on the dash?  Maybe try adding some fuel system cleaner (whatever brand you prefer) for the next couple tanks of fuel.  Did the aftermarket intake change anything or was the problem happening before?

[Mike GMC]

Run a compression check and maybe a leak down test.  My guess would be bent push rods or maybe a broken valve spring.  Could also be an issue with excessive cam wear.

[ChevMech]

The check engine light has not come on. I did notice a slight power increase when I replaced the filter, but that was because the other one was insanely plugged. 

 

My next step is to do a compression test, and while I have the plugs out, I'm going to pressurize the cylinders to see if I can hear anything in the intake, exhaust, or crankcase. I don't have a leak-down kit, but I'm sure I'll get one since I'm going to have it so far down.

 

Another thing I failed to mentioned is the loud ticking. I've read that these engines are prone to that to begin with, so I've haven't paid it any mind. Everything mentioned above could be causing this now that I'm thinking about it more.....

[ChevMech]

Hello all,

 

I wanted to follow up with everyone about my progress with the aforementioned problems I've been having. 

This past weekend I stopped by the local parts store and purchased a can of carb cleaner and a can of mass air flow sensor cleaner. I disconnected the batter (to reset the ecm), cleaned the MAF and throttle body. It's hard to say how bad the MAF was, but the throttle body was gummed up pretty bad. I put everything back together and now it seems like the truck has a little more power. What I wasn't expecting is how quiet the engine is under load. Before, it had a pretty audible roar. Now, its much quieter. We'll see how this, combined with a can of Seafoam in the gas, will improve performance.