I'm pretty new to owning a diesel and as winter is coming and some nights and mornings are very cold... I just wanted to know if my 2001 Dodge cummins uses more fuel when cold. It seems to be that way, and if it is a significant amount, what can I do to help improve my fuel economy in the winter time?

 

Not much. You have a full size pickup (2500 no less) with a diesel engine. Fuel economy was tossed out the window with the purchase of that truck. I'm sure jigabop will contradict as he has the baddest truck of all, but "Ram 2500 diesel" and "fuel economy" should not be used in the same sentence.

 

he meant "Ram" and "fuel economy" shouldnt be used in the same sentence

 

^^yeah, that.....

 

I do believe a diesel is going to use more fuel when cold compared to a gasser as it takes longer to get heated up and working properly.

However the overall fuel savings and power increase out weighs that.

 

Any engine, regardless of fuel type, is going to use more fuel when cold out.

 

Yep, plus the fact that the gas companies put additives in the fuel during the colder months, that contribute to worse MPG's.

 

I hate to tell y'all this, but the answer is no.....

compression fired engines don't monitor o2 content and adjust trim to compensate... air makes no never mind, except that without it the injectors become tiny cutting torches that will cut through pistons like butter... more air makes for leaner burn, which makes less smoke-n-soot than a rich engine will make.. cold(er) air on the intake keeps exhaust gas temperatures lower, which in turn keep boosted (turbo) temperatures lower, which puts more air in the cylinders per intake stroke, but has zero implications for fuel delivery... that is the characteristic of a diesel- their power is based on amount of fuel delivered, not air moving through like a gasser does.. without the air, the diesel would melt itself quick like. more air moving through a diesel keeps the temperatures lower and prevents that.

gassers move air, and ignite it using fuel as a catalyst to ignition.. diesels don't.. they squish air and oil to the point it detonates... call it a controlled ping.. a gasser regulates RPM by using blades in the carb or throttle body to regulate air inducted.. a diesel does the same thing, but with fuel delivery instead of air... they both measure pressures (maf or map) to determine how much fuel based on pressure or flow of air, but a diesel could care less what the temperature is.... what a turbo diesel DOES care about is turbo pressures, which are much higher with colder air, and cause higher fuel delivery based on the higher volume of air- but again, that can be regulated using your foot, and re-learning how to drive your diesel in cold environments.

winter blend diesel means 10% #1 diesel to 90% #2 (regular ulsd highway diesel), and to keep the diesel from gelling.

 

i didnt have time to read all that "drewactual" said but what i did read he is VERY correct. ie a diesel engineis are TOTALY different than a gasoline engine. BUT one thing is the same they burn air "oxygen" and hydrocarbon. when the two mix in the chamber you lots of water. YEP. ALMOST a gal of water for a gal of gas / diesel fuel. if the air being pulled in is cold it will cause the fuel to not burn good.

 

Air temp does play a role. Colder air is denser, so, any engine management system that pays attention to how much air it 'thinks' is in there, is going to add more fuel when it sees colder air. Now, on the older 12V engines, they just don't care. At all. Fuel injection is purely mechanical, and the only thing that changes how much goes in, is how hard you are stepping on the go-pedal.

Now, one COULD argue that you don't have to step on the pedal as hard when it is colder out....... or vice versa...... but, then we start delving into theory, and that just makes me head hurt.