hi guys,
i got this big problem with my truck :cry: i'm getting only 5-6 mpg.
i have a 14l 500hp ditroit s-60 in my truck(century). i'm on a dedicated run from newark nj to columbus oh, i run on pa turnpike. on my last trip i got 5.2 mpg. 24000 lb on my back. i took it to ditroit diesel in columbus, they've cheked my fuel presure, cac, updated tha software. i'm still in the same boat. tire presure good fuel filter is clean. brakes dont drag.

any idea :?: :?: :?: thx.

 

What year is your truck and how many miles? You may need to get an overhead ran on it, not an overhaul. Sometimes the Detroit dealers are not bright. My dad has had similar experiences, he take it to them and they can't find it! I'm sure the CAT and Cummin dealers are the same way too.

 

- alignment
- tire pressure
- tire model(what tires do you run?)
- what specs do you have?
- turn on all fuel mileage settings in the ECM(progressive shifting, turn down hp to a "split hp", softer cruise resume settings, lots of them on detroits)
- reduce trailer gap
- eliminate idling
- free flow muffler

I could go on and on...

 

is your air filter dirty ? how was the weather ? i usually get 7 mpg & 2 weeks ago i got 4.9 mpg. it was raining out & i had a headwind 25-35 mph. after a couple days the weather changed & my mileage went back to normal. all of us on our dedicated run had the same fuel exp... just a thought. det are usually good on the fuel.

 

Detroits sweet spot is 1450/1500 are you cruising in about that range, are you trying to keep your shift points at or below 1500?

Also you don't want to pull below 1050

Mike

 

Detroits sweet spot is 1450/1500 are you cruising in about that range, are you trying to keep your shift points at or below 1500????



hmmmm.. well on my 11.1 det i shift at 1600/1700- 1450 /1500 seems to low for me. if i did i would be luging the next gear. 1450 with a 45,000 lb load 7 its hard to get rpms & speed back up. with my truck anyway[/quote][/list]

 

Ya Heavyhauler I pretty much shift at 1600/1650. I was told by a Detroit Diesel rep at a truck show I think it was to keep shift points below 1500 for the best fuel milage.

I have always wondered if all of the S60's have the same characteristic as for as shift points, sweet spots and lugging. DAF has a 14Liter, I have a 12.7 liter and you have a 11.1 liter. Do they all pretty much run the same?

Thanks Mike

 

first of all thanks for the reply to you all.
i have low pro tires 22.5. it's got 670500 on it and i just got a overhead 2 months ago. i do not idel, got a generator. i noticed one thing, i got a pm about a 4 weeks ago. from oh to back home(nj) i got 7.2 on flat road, than it went down to 6.5. i was happy with it. the way back it was f....d up again. i shift at 1500-1600. 13speed trany 3:58 reals.

 

You'd never make it anywhere with my 500 detroit. It will NOT produce manifold pressure below 1300 rpm. I shift at 1800, which drops it to 1300 and it does okay, no more. It really runs good if you shift at 1900 to 2000 rpm, but I rather ease around with it. Anyhow, once she drops below 1300, you've lost it, it just falls on its face.

 

Looks I am glad I have a 12.7 430hp.

I have put 250,000 miles on this truck & I have never seen 1,900 rpms, but I only put 48,000 to 51,000 on the deck