Cat 3406E Question! MPG Poor at 3.5-4 mpg.

That could be part of the problem. Caterpillar will give you the low nox file instead of the high nox file due to emissions regulations. It does wonky stuff like not turning the fan on until 217* and makes it just run worse in general.

 

When was the last time the overhead was run? How old are the injectors? Double check oil for fuel dilution.

 

that's definitely part of your problem!!
Have you checked for boost leaks, exhaust leaks? what's your fuel pressure?
I ran a 700hp tune for years on my cat, constant stop/start, high idle time and everything else that can kill MPG an could avg 5.

 

Take that boost number and write on a piece of paper. Then use that for toilet paper . I’m gonna use random numbers here let’s say 27 psi is hard on fuel and underpowered if it’s 27psi with a leak. 27psi no leak is a completely different than 27 with no leak. You’re gonna want to stop the fresh air inlet into turbo and check it all not just air to air. Then look at over head set it up right. Check turbo wheels especially the exhaust side you can’t see till it’s out of hot box. Before “tuning” one it’s best to give it a complete once over and fix any little trouble you find. Most if the time you have a couple small problems creating a bigger one. The tune is only going to mask that.

 

Bobtail Member

Looking to change my stock 8501s from my 6nz I have 3 2780s and 3 9035s they are cross numbers for the 8502s wondering if I can pair them together​

 

When was the last time you were looking for an 18/13 speed, no core youre looking at 5k for a used takeout that looks like its already dead and 9k for a rebuilt

 

I just put a 13sp in my truck this January rebuilt one was 4,950$ In Portland, Or.