Changing tire size programming

[Crunchy]

The truck has 9500 on it. I will look into some kind of fuel additive. Fuel filter has another 22% before the comp says they are needing to be changed.

[Alchase]

The truck has 9500 on it. I will look into some kind of fuel additive. Fuel filter has another 22% before the comp says they are needing to be changed.

Crunchy, what vehicle and motor?

Only 9500 miles, and you saw a noticeable MPG decrease?

Shouldn't it be under warranty? I would have them check it out.

[Crunchy]

Ram 2500 with the cummings.  if I had to guess it would be a combo of the tire size, cold weather with more warm up time idling, and little more city driving than usual.

[Alchase]

Nothing dramatic on size, I went from a 295/65/20 to a 285/70/20

Yea, that's not much of a change at all. Only works out to about 10 revolutions per mile less. Hardly enough to make any noticeable difference.  Could be your truck is more sensitive than some or, like someone else mentioned, maybe the shift in fuel blend.

For a Ram 2500 with the Cummings, I would bet the tire change was insignificant to the issue.

[Crunchy]

Fuel filters are cheap. Lots of crappy fuel out there. I keep an extra stock spare in the truck.

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I change my fuel filter every other oil change, and coach told me to add fuel additive with every tank. 

which additive did he recommend?

[Special T]

I went up 8% in tire size and saw  a decrease in Hwy milage...
I would bet that that 22% sat is based off mileage, just like the oil change stuff is. OR  idling your your Cummins to warm it up is having an effect on your Emmisions garbage.
 The fuel filter on my dodge is less than $25. Any noticeable difference in mileage pays to put in a new one.

All that computer calculated output is just bells and whistles. Unless there is some kind of fuel drag/resistance sensors I'm 99% certain it's based on mileage, just like how check engine light tend to come on during service intervals. 2c

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[jackelope]

The truck has 9500 on it. I will look into some kind of fuel additive. Fuel filter has another 22% before the comp says they are needing to be changed.

Crunchy, what vehicle and motor?

Only 9500 miles, and you saw a noticeable MPG decrease?

Shouldn't it be under warranty? I would have them check it out.

He put bigger tires on it and it's winter.
There's nothing wrong with the truck.

[jackelope]

Fuel filters are cheap. Lots of crappy fuel out there. I keep an extra stock spare in the truck.

Sent from my SAMSUNG-SM-G930A using Tapatalk

I change my fuel filter every other oil change, and coach told me to add fuel additive with every tank. 

which additive did he recommend?

Maybe a quality cetane booster?

[Woodchuck]

I run white bottle Power Service in my truck, every tank. fuel filter once a year.

[jackelope]

I went up 8% in tire size and saw  a decrease in Hwy milage...
I would bet that that 22% sat is based off mileage, just like the oil change stuff is. OR  idling your your Cummins to warm it up is having an effect on your Emmisions garbage.
 The fuel filter on my dodge is less than $25. Any noticeable difference in mileage pays to put in a new one.

All that computer calculated output is just bells and whistles. Unless there is some kind of fuel drag/resistance sensors I'm 99% certain it's based on mileage, just like how check engine light tend to come on during service intervals. 2c

Sent from my SAMSUNG-SM-G930A using Tapatalk

That fuel filter % is based off of a combo of miles, engine hours and engine work load.

Same way as our oil change intervals work now.

[trophyhunt]

With my truck going from stock to a 6” lift with 35”x 12.50x20”, do you guys feel it’s pretty important to buy a programmer ??

[jackelope]

Your speedo is definitely not accurate.  I would assume you're losing some performance because of it too. Shift points will be off, etc.

[trophyhunt]

Your speedo is definitely not accurate.  I would assume you're losing some performance because of it too. Shift points will be off, etc.

yes, Speedo is off, it still shifts nice but I’m positive it could be better. My diesel mileage sucks, about 11.5 per gallon pulling a loaded trailer or not.

[Crunchy]

Your speedo is definitely not accurate.  I would assume you're losing some performance because of it too. Shift points will be off, etc.

Dealership job, or other options?  When I first got the truck I was averaging about 16, after it broke in I was getting nearly 20.  Now it has shot down to about 16 again.  Other than tires, and an oil change nothing has changed.

[horsehunter509]

The truck has 9500 on it. I will look into some kind of fuel additive. Fuel filter has another 22% before the comp says they are needing to be changed.

I never run mine to 0%. Normaly do fuel filter between 20-25%. Not worth pushing it any further for me.