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

Can you lower boost by adjusting the WG? Absolutely

Do you know what EGT's would do then?

Do you know where your EGT's are now?

 

EGT would go sky high
EGT run now between 400-900

 

I had a 1994 5EK series and had a tune in it. It had the horses to get you were you want and still got 7 mpg all day long.

 

My truck has a 3406 B with a 15 speed and 3:90 rears, sitting on 24.5s. I run it hard seasonally, very similar weight to you, and I usually get 4.5-5 mpg. Last fall I pulled a reefer for a friend of mine for several months, and cruising longer distances, I was up pushing 6.3-6.5. 60 mph I have about 15 lbs of boost, put my foot in it, we can see 34.

 

Did a diesel shop do the tune for you, or a buddy? A bad tune is worse than no tune

 

If you’re referring to my post, I did the tune. I put the file in it, actually tried several but settle for a 550 BrakeSaver tune. Also dropped a Stage 1 B/W turbo(no wastegate) the tuned called for 57 injectors, I had 58’s.

 

Take that 15 speed and use it for the only thing they are good for, a boat anchor. Put an 18spd in it or 13 speed, you can usually find a decent one for around $3000.

 

Was actually referring to the OP. Should be able to do much better than 4 mpg on an E

 

X2

 

x3, one thing I’m very glad have gone the way of the dinosaurs

Sounds like a combination of a bad tune and a bad foot

did I miss OP location or did he not share that?