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?

 

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?