wiserfrombud

Is there not a throttle % readout on the digital screen in the center of that dash? I can't remember, I am not in the truck right now. I would think you should be able to depress the pedal with just the key on and watch that the percentage is reflecting what you are doing with the throttle. Just a thought. You could certainly check that with the service software at the dealer, but there goes another 100 bucks. I would try that.

That's brutal about all the junk in the tank etc.... I hope that doesn't give you any further problems. I would get 25 000 miles on it or so and do another good full service analysis on the oil. I am reasonably good at deciphering these things now. Post results on here to see what's really going on with the motor. It won't tell you everything, but it will tell you a fair bit.

No its all good, I spent a pile of Money @ Cummins on my KW. Every time I went there and I always left with the same issue or worse. I gave up with them and worked with my local repair shop who me I have a great relationship with. I eventually got it back to about 95% running properly for a fraction of the cost. The old saying if you want something done right, you do it yourself has never been more true.

If none of this helps, maybe try posting some of this in the engine forums?? I have only owned my Mack for 5 months. I am not a certified tech or anything, but this is now my 3rd emission truck as well, so this isn't my first rodeo either. My last truck was a 10 kw 660 with an ISX. I had a fair number of issues with that motor so I am just brain storming with you. Both motors use that pos Holset VGT turbo. It's great when it's new. They don't last, they aren't cheap to replace, and have fun finding a shop that truly knows how to set it up properly!

What are your lanes and how heavy is your freight? That truck is going to struggle with 80 000 on most any type of hilly terrain imo. If you run 45 000 gross across Texas, it should be a great spec.

If the turbo is original and it's never been off, there is no reason for it to be out of calibration. How long ago did you purchase the truck? It was bought from the dealer you are speaking of? I think if it were ME, I would pull a full service oil sample from a lab. Not bench top bs. If your turbo is out of whack, you should be seeing elevated soot levels.

Hmmmmmm. How is the DEF usage? Did you have them clean the DPF just for good measure before you bought it or was there a soot load/frequent regen issue?

Something does sound out of whack now with that explanation, because mine certainly does not behave like that.

How many miles are on it? Has the turbo ever been replaced? If so I wonder if it was calibrated improperly?

Hmph. It's on big rubber but still.....I am surprised you find that thing to be such a slug. 800 degrees sounds like it's getting all kinds of fuel to me. Maybe try getting the + update as suggested earlier?? I'm not sure what else to think about that. Mine I am very happy with the performance out of mine for a 13 litre!

394's!? Wow. That's geared pretty low. On what size rubber, and what transmission?

Btw the E is the economy designation I believe....if you aren't happy with the C, you certainly would not wish you had an E.

Btw the E is the economy designation I believe....if you aren't happy with the C, you certainly would not wish you had an E.

Oh I see you were comparing it to your 09. I can't see that 12 being every bit as strong as your 09 and then some provided you are comparing apples to apples. Same spec, load, terrain etc.... if the 09 had 411 rears, and this new one has 36 rears, that will be a noticeable difference for sure.

Ol well what is the truck spec'd out to do? 87,000 lbs is a pretty good load. What rears are in it? When you say it doesn't pull very food down low. Compared to what? Are you unhappy with it because you can't accelerate with traffic from a light? To me an underpowered truck is when you are pulling a hill, and it will not pull a grade in anything higher then 3rd gear. If I takes you a while to get rolling, or you have to grab a few gears in the grades, so what?

And for what it's worth, I am almost always 80 000 lbs gross running the I15 corridor from California to the Canadian border. Lots of good pulls on that route.

What is the torque rating on that motor? It's rated at 1860 like mine right? In my experience horsepower is just kind of a byproduct of torque. Hp doesn't matter nearly as much in how the truck pulls as torque.

I usually shift around 1300. It's tough to tell how a truck is running just off of the boost gauge. With the variable geometry turbo's, the boost constantly fluctuates based on ambient temp, elevation, and state of the emissions system at any given time.

If its running right, it should pull better down low. I have a 16 505c+ and it's peak torque is 1050 to 1400 rpm, I believe is what the literature said. It is usually around that 800 degree mark on a grade. The only thing you are doing at 1700 with these newer engines is making noise and wasting fuel. I understand mine is a + and has the same torque in all gears, but even without the +, I'm fairly certain the curve stays the same.

Big enough job! Your a champ. I wouldn't have had the patience to do that. Haha.

Wait, you changed a RAD in the church parking lot? Or the lower hose?

Yup. I don't think anybody could deny emissions trucks have their share of issues, but from my experience it hasn't been nearly as bad as all of the pre emissions fans make it out to be. I made a good living with my two previous emissions trucks (2005 379 pete/2010 kw t660 both ordered new)and plan on doing the same with my new Mack. I am not willing to sacrifice all of the creature comforts of a new truck. This Mack rides nice, it's quet, I love the lighting, and the climate control is second to none! So far I am very happy with it.

Just a heads up, I run 55 when I have time and 59 when I'm in a hurry heh. So keep that in mind with that fuel mileage number. However that is miles divided by gallons since new. Not some finger in the wind, smoke up your ass number like most throw out there when asked their fuel economy. Also keep in mind, always heavy, hilly terrain, and 505 horse/1860 torque in all gears. This thing performs like a champ. Pulls every bit as good as my BXS C15 and my CM871 ISX both rated approximately the same.

I have a 2016 CXU 613. MP8, 505c+, Eaton 13 speed, mack twin Y/rears. I have had it for almost 3 months now and have loved it since day 1. It has 30 000 miles and it's 90 day average is 7.38 US MPG running the I 15 corridor between Canada and California, loaded 75 to 80 000 lbs all the time.