Insane Fuel Consumption.

[SolidWaste]

2008 Dodge Ram 2500 Hemi 5.7L with 4x4. Until the last couple of months I had roughly 12 miles per gallon. I dont know what has happened, but when I noticed an employee was filling the tank every other Day; I averaged it again and it came out to 5 to 7 miles to the gallon. I have already pulled the Coil Packs, Spark Plugs, Injectors, Air Intake / Mass air sensor, Oxy sensors and cleaned the cat. I even pulled the tires and checked the Brakes to make sure they werent putting pressure on the rotor constantly. I cleaned everything and made sure it was all in working order and there still is no change. Nothing was damaged so I didnt replace anything.
I also noticed a weird Idle. Not rough but inconsistent. It will rev up then down slightly and the smaller side fan turns on and off. Coolant temp senors was tested and passes and the engine doesn't overheat.
Is there some issue I am overlooking? Has anyone else had this problem? We are a County Department and the Department that had it before us did not take care of it, but again. No appearnt signs of damage on the parts mentioned. I am fully stumped and would greatly appreciate some insight from someone who more than I. Thank you for your time!

 

[06 Dodge]

If all other things checks out the I would assume that a lack of control for the right foot should not be over looked......

 

[Ken226]

2008 Dodge Ram 2500 Hemi 5.7L with 4x4. Until the last couple of months I had roughly 12 miles per gallon. I dont know what has happened, but when I noticed an employee was filling the tank every other Day; I averaged it again and it came out to 5 to 7 miles to the gallon. I have already pulled the Coil Packs, Spark Plugs, Injectors, Air Intake / Mass air sensor, Oxy sensors and cleaned the cat. I even pulled the tires and checked the Brakes to make sure they werent putting pressure on the rotor constantly. I cleaned everything and made sure it was all in working order and there still is no change. Nothing was damaged so I didnt replace anything.
I also noticed a weird Idle. Not rough but inconsistent. It will rev up then down slightly and the smaller side fan turns on and off. Coolant temp senors was tested and passes and the engine doesn't overheat.
Is there some issue I am overlooking? Has anyone else had this problem? We are a County Department and the Department that had it before us did not take care of it, but again. No appearnt signs of damage on the parts mentioned. I am fully stumped and would greatly appreciate some insight from someone who more than I. Thank you for your time!

Our fleet trucks show horrid mileage like that when the employee leaves it idling for hours. The gallons burned @ idle without any miles accumulated, results in a horrid MPG number on the instrument cluster.

 

[tron67j]

I would do a couple full tanks yourself, drive normal and not feathering it to artificially get the best out of it, and see what you end up with. That way you know what a normal use mpg is with idling, A/C time, etc. all captured. As stated above. It could be left idling for hours with AC on, for example, and that would kill mpg value.

Have you checked for any codes even though engine light may not be on?

Could be a vacuum leak. Maybe a fuel pressure problem; you could install a pressure gauge to monitor it. Have you checked air filter for debris restricting air flow? Could try cleaning the throttle body.

I don't know where or how it is driven, but you could jack front end up and make sure wheels turn freely and verify no brake drag, bearing problem, and that the front 4wd is fully disengaged (I know it would probably tear itself up if not, but just thinking out loud about free things to check).

 

[crash68]

I also noticed a weird Idle. Not rough but inconsistent. It will rev up then down slightly and the smaller side fan turns on and off. Coolant temp senors was tested and passes and the engine doesn't overheat.

It could be the air conditioning cycling causing the up/down of the idle but you may have an air leak on the intake side of the engine.

 

[Rado]

All great advice above !
Check the idle hours meter to see if he idles too much !
Maybe could be the catalytic converter may be starting to plug ?
Did the excess consumption just start or only with same driver ?

 

[SolidWaste]

If all other things checks out the I would assume that a lack of control for the right foot should not be over looked......

Yeah. Its an employee driving it and he isnt very.... well common sense isnt all that common.

 

[SolidWaste]

I would do a couple full tanks yourself, drive normal and not feathering it to artificially get the best out of it, and see what you end up with. That way you know what a normal use mpg is with idling, A/C time, etc. all captured. As stated above. It could be left idling for hours with AC on, for example, and that would kill mpg value.

Have you checked for any codes even though engine light may not be on?

Could be a vacuum leak. Maybe a fuel pressure problem; you could install a pressure gauge to monitor it. Have you checked air filter for debris restricting air flow? Could try cleaning the throttle body.

I don't know where or how it is driven, but you could jack front end up and make sure wheels turn freely and verify no brake drag, bearing problem, and that the front 4wd is fully disengaged (I know it would probably tear itself up if not, but just thinking out loud about free things to check).

That is my next step. The entire air intake and throttle body was removed, cleaned and inspected. I need to look at the GPS reports to see but he probably parks it and sleeps, knowing him. When i spend the front tires, it moves the front drive shaft. Does that mean the 4wd is ingaged? I'm not a mecanic and that probably sounds like a stupid question.

 

[SolidWaste]

All great advice above !
Check the idle hours meter to see if he idles too much !
Maybe could be the catalytic converter may be starting to plug ?
Did the excess consumption just start or only with same driver ?

No. New driver. He is filing the tank every other day. He didnt have this issue when I first let him start driving. I want to give him the benift of the doubt, but it is getting hard. When I spin te front tire, the front drive shaft movess. Shouldnt that spend freely if the 4 wheel drive if off?

 

[Rado]

No. New driver. He is filing the tank every other day. He didnt have this issue when I first let him start driving. I want to give him the benift of the doubt, but it is getting hard. When I spin te front tire, the front drive shaft movess. Shouldnt that spend freely if the 4 wheel drive if off?

I have no clue about the drive shaft as I am no mechanic so no help !
But am curious about it and hope a gear head chimes in that can help !
Please UPDATE what you do find out !
Any codes ?
Maybe O2 sensor going bad ?
A buddy of mine was getting lower mpg till they change the O2 sensors and he started getting about 2 or 3 more mpg !
But I think they also through a code
Thanks!

 

[zrock]

Well it is a 2008 work truck, unit could be getting millaged out and the engine is on its last legs. I would be doing a compression check and seeing what condition the engine is in. You may have a dead cyl or 2

 

[Dean2]

No. New driver. He is filing the tank every other day. He didnt have this issue when I first let him start driving. I want to give him the benift of the doubt, but it is getting hard. When I spin te front tire, the front drive shaft movess. Shouldnt that spend freely if the 4 wheel drive if off?

Based on this comment and one other you made about checking the GPS and common sense, I would either have him working where he is directly supervised or fire him. If you really think he is parking and sleeping, the gas mileage on the pickup is a minor issue, especially cost wise.

 

[Evguy1]

I knew a guy that siphoned fuel out of the company truck every tank so it was consistently low MPG.

 

[Rado]

I knew a guy that siphoned fuel out of the company truck every tank so it was consistently low MPG.

That IMO is more common today with the way people think today :O

 

[SolidWaste]

I have no clue about the drive shaft as I am no mechanic so no help !
But am curious about it and hope a gear head chimes in that can help !
Please UPDATE what you do find out !
Any codes ?
Maybe O2 sensor going bad ?
A buddy of mine was getting lower mpg till they change the O2 sensors and he started getting about 2 or 3 more mpg !
But I think they also through a code
Thanks!

O2 sensors are what I am checking next. They are in such a dumb spot. On top and the cat obviously isnt removable unless i want to cut it, but i need it installed to test. I'll just have to try and try i guess! No codes. I have a few tests I can do while driving with my OBD2 tool. I will be sure to update just incase it helps someone else; if I figure this out.

 

[SolidWaste]

Based on this comment and one other you made about checking the GPS and common sense, I would either have him working where he is directly supervised or fire him. If you really think he is parking and sleeping, the gas mileage on the pickup is a minor issue, especially cost wise.

That was meant to be a joke, I am sorry if it didnt come off that way. He has ethic issues I am trying to work through, but I dont think he would honestly sleep. I also surprise check on him! lol
But other issues may lead to the same results. Thank you for your input and I am just really trying to not have to.

 

[SolidWaste]

I knew a guy that siphoned fuel out of the company truck every tank so it was consistently low MPG.

Well. I am installing a Camera today. Thank you for an idea I didn't even think about.

 

[Wild one]

Well. I am installing a Camera today. Thank you for an idea I didn't even think about.

Newer vehicles are harder to syphon fuel out of now,but way back when i was a kid i knew a guy who worked for a towing company,and he had a cheap electric fuel pump rigged to a a couple jerry cans,and he was syphoning fuel out of pretty well every vehicle he towed,he was selling it cheap to a few of the local young guys.He was finally caught redhanded by a vehicle owner who'd followed him to the side streets where he was doing the syphoning,and he was leaking a bit of blood* when the vehicle owner was done with him,and looking for another job,once the owner of the towing company was informed

 

[EdGs]

Newer vehicles are harder to syphon fuel out of now,but way back when i was a kid i knew a guy who worked for a towing company,and he had a cheap electric fuel pump rigged to a a couple jerry cans,and he was syphoning fuel out of pretty well every vehicle he towed,he was selling it cheap to a few of the local young guys.He was finally caught redhanded by a vehicle owner who'd followed him to the side streets where he was doing the syphoning,and he was leaking a bit of blood* when the vehicle owner was done with him,and looking for another job,once the owner of the towing company was informed

Karma is a B I T C H !!!

It always catches up with you.

 

[Bighorn_Brown]

Didn’t read all the posts. Someone may have mentioned it already, but I’d suggest you should look for a vacuum leak. As the vehicle sucks in more air as a result of the leak this will be reported to the BCM. Which will then compensate by dumping more fuel to equal out the air to fuel ratio. Hence, the excessive fuel consumption.