5.9 Liter CR Dodge Cummins 03-07 Discussion of 5.9 Liter Dodge Cummins Diesels with Common Rail Injection

Why is my fuel milage so bad?

Thread Tools
 
Search this Thread
 
  #11  
Old 10-07-2009, 10:04 AM
AF1CUMMINS's Avatar
Diesel Bomber
Join Date: May 2008
Location: Sumter, SC
Posts: 1,034
Received 54 Likes on 37 Posts
Default

Somebody tried to recalculate for 35's on my 2nd Gen but he said if he did that then the Smarty wouldn't work on his truck anymore? Anybody know if this is true or were we just doin something wrong?
 
  #12  
Old 10-07-2009, 10:08 AM
Red_Rattler's Avatar
High Tech Redneck

Join Date: Nov 2007
Location: Columbus WI
Posts: 6,730
Received 496 Likes on 397 Posts
Default

That is true since your changing the stock programing in the PCM then it's vin locked since it has to save your factory program. All you can do without vin locking it is checking trouble codes...
 
  #13  
Old 10-07-2009, 12:24 PM
tdiezel's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2009
Location: Belen
Posts: 410
Received 13 Likes on 13 Posts
Default

I forgot that was required with a smarty. Oh well. I found a fella down here that does independent diesel mechanic work and from what everyone says, he's damn good at it too. I was told he could do everything I need so I am going to go ahead and give him a call. Also, how do you clean the sensors? With a wire brush or something?
 
  #14  
Old 10-07-2009, 12:26 PM
Wyatt Earp's Avatar
Diesel Bomber
Join Date: Mar 2007
Location: Nanaimo, BC Canada,
Posts: 2,015
Received 102 Likes on 98 Posts
Default

No. Pull them out with the applicable socket, clean them with a dry lint free cloth or some sensor cleaner - never use any harsh chemicals.

You can thank me later.

Cheers,
 
  #15  
Old 10-07-2009, 12:42 PM
tdiezel's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2009
Location: Belen
Posts: 410
Received 13 Likes on 13 Posts
Default

Lol well I wasn't contemplating dipping it in vinegar but I do appreciate the tip! Thanks Wyatt!
 
  #16  
Old 10-07-2009, 12:59 PM
Wyatt Earp's Avatar
Diesel Bomber
Join Date: Mar 2007
Location: Nanaimo, BC Canada,
Posts: 2,015
Received 102 Likes on 98 Posts
Default

No worries.
 
  #17  
Old 10-07-2009, 04:35 PM
tdiezel's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2009
Location: Belen
Posts: 410
Received 13 Likes on 13 Posts
Default

So I drove about 50 miles today and I noticed that if I slowly came up to 2000rpm and then shifted and kept it close to 2000rpm I got better gas milage than when I only sat it at around 1300rpm just cruising. I know they need to operate at a higher rpm but could my rpm and speedo gauges both be off?
 
  #18  
Old 10-08-2009, 08:35 AM
cumminsdad08's Avatar
Diesel Enthusiast
Join Date: Jan 2009
Location: lebanon Pa
Posts: 483
Received 28 Likes on 28 Posts
Default

mine runs the absolute best around 2,000 rpm. i ran a 400 mile round trip holdin it at just around 2,000 the best i could, and i got around 20- 22 mpg, most all highway. thats with 35x12.5r17, AND an alignment that was WAY outa wack. without my juice.
 
  #19  
Old 10-08-2009, 12:00 PM
tdiezel's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2009
Location: Belen
Posts: 410
Received 13 Likes on 13 Posts
Default

Hmmm maybe my rpms are off pretty bad then. I just had it aligned. I will call today and get they speedo and rpm fixed.
 
  #20  
Old 10-11-2009, 12:46 AM
tdiezel's Avatar
Diesel Enthusiast
Thread Starter
Join Date: Aug 2009
Location: Belen
Posts: 410
Received 13 Likes on 13 Posts
Default

Well I'm super e xcited to say I'm getting better gas milage now. I changed the oil and it made a huge difference. I filled up my truck and got 200 miles out of a half tank, that's 50 miles every 1/8th of a tank! Well needless to say I drove it after the oil change, with 200 miles on the odometer and 80 miles later I only used an 1/8th of a tank! That even included racing with a guy that quite literally whipped my ***. He had to have had a chip but he didn't have any visible gauges so I don't know what he was running but he was quick. Anyways just wanted to thank everyone for their help and advice!
 


Quick Reply: Why is my fuel milage so bad?



All times are GMT -5. The time now is 05:36 PM.