2007 5.9 turbo bark and bad MPG's

[RWarhol]

I have a 2007 3500 5. 9 automatic and when i let off the gas the turbo barks, but not all the time. Also the oil is very black and full of soot. The mpg's are ten or lower. Has anyone else had these problems or a fix for them? Because the dealer knows nothing, they replaced the number six injector about two weeks ago but its not much better.

 

[roperteacher]

Black oil is normal on these trucks, I have an 07 5. 9 stick so not the Auto. My truck just turned 14,000 miles and I am seeing 22-23 Empty Hwy, 19-20 around town, and about 13-14 Pulling my large trailer. Less than 10 is not cutting it. .

 

[JCleary]

Less than 10 is pretty bad...

I average 12 around town. Highest tank to date (6k miles) is 16. 1

I would recommend traveling to a 5-star dealer and have them diagnose the problem.

What does your overhead read?

 

[Vaughn MacKenzie]

Welcome to TDR RWarhol. Have you had a turbo diesel before? It takes a little skill & conscientious throttle operation to prevent turbo bark especially on an automatic. Basically you're letting off too abruptly when you have boost built up, and with the sudden loss of exhaust drive the pressurized intake side tries to push back, creating the huffing sound. Try letting off the pedal slowly, it'll solve you barking.

Starting with the 600 series Cummins (04. 5 model up) oil soots up very fast, it's believed to be caused by the 3rd injection event late in the combustion cycle. Oil samples run from these engines prove how badly they soot it up. If you're truck isn't running perfectly right then likely makes the problem worse.

 

[rbattelle]

The mpg's are ten or lower.

I echo Vaughn's comments on turbo bark. But the fact that you're barking the turbo regularly suggest to me that you're driving with a lead foot. That's the best way to kill your fuel economy.



Remember - the single most important determinant of fuel economy is driving style.



Ryan