Anyone ever heard of a Charge Air Cooler going bad and causing this much drop in mpg?

 

 

I have dealt with them in the past. They are not cheap, but usually charge less than the local dealers. I don't believe they are open on the weekend, but their number is 423-622-1006.

 

Have you noticed a loss of power?

I had some sort of nest sucked up into my turbo. Whatever was in it, damaged the impeller. I'll bet I lost 50 hp and some fuel mileage. Going to replace the turbo someday.

Possible restriction in the intercooler?
Maybe something in the air intake system?
Have you noticed any increase of black exhaust?
Is there air pressure in your tires correct? Maybe some goober is playing jokes.

 

If you have a boost gauge, what's it doing? Yes, you would lose mpg if you had an air leak somewhere in the charge air cooler.(intercooler)same thing. Make sure all your hoses and conections to your air cooler are secure and tight. What about the turbo? Sometimes they can slowly crap out on you and you would lose mpg.

 

Yes, check the charge air cooler.

They block both sides, pressurize it to about 30 psi, and notice the boost loss over about 15 seconds. Do this ASAP.

If it's more then 3 psi, change it.

Also, I think sonny is giving some excellent advice, someone may be skimming your fuel.

You changed fuel filters as well correct?

ULSD doesn't affect fuel mileage that much. I run it almost exclusively and my fuel mileage this year is the best ever.

 

Hi Papa Rick! did you find the problem? What was it?
I have the same problem C-15 -4.4 mpg before i got 5.5-6 mpg!!!

 

Dual turbo? I'd sure have a look if so. A friend of mine keeps losing the top turbo, don't know why. But it does knock the hell out of his mpg. He says there is a big power difference though, of course he runs pretty hard too.

 

See all the different things that can affect the fuel economy of an engine.

Now...weak turbo has been suggested...that can be tested.

Charge Air system leaking...that can be tested.

Fuel filter dirty? That can be changed.

Rack needs to be run? Well..they will see how far out of sinc the injectors are, when they tear into them. My rack cost me $469.00 to have done.


Now...on the fuel portion of the equation. Are all the hoses in good condition? Any wet spots? I wouldn't have believed it, but something as simple as a weak hose can lower your mpg with an electronic engine.

Another thing that lowers fuel economy is Bio-diesel, especially the 855 blend. You can lose 1/2 mpg with that stuff easy. I try to avoid it as much as possible.

 

There are a few guys around here that bought new trucks with the C15 and have the same complaint, economy seems to get worse the more miles you put on it, they all have less than 300k. One guy said Cat put out a tech bulletin and even a video on how to drive the C15 for best fuel economy, dont know if its true or not but you may check with Cat for a tech bulletin.