Mpg Bad Bad And Bad

[viper700]

Disel Dave

On my 04. 5 dually I installed the quad box for towing. You cannot use the over head comp for your mileage. You have to hand calc. I was getting by the over head 18. 4 mpg not towing, when I installed the box I went to 22 mpg. The box does something to the comp and fools it on how much fuel you are burning. I now get with the box hand calc'ed 17. 4 not towing and 9. 5 to 12 towing my 15k 5er. Power is great and runs real smooth. Don't believe the overhead reading. I have 39k on the truck.

 

[Disel Dave]

Driving style

Sounds to me that you should look at your driving habits. If every car, truck , and boat you drive gets bad mileage, did you ever think it could be... 1. Aftermarket mods or 2. The person in the driver seat. Try having your wife drive and see what she gets. The one and only time I pulled my 26' trailer to the Oregon coast on a 2 lane hill type winding road, I still got 15 mpg in my 04. 5 CTD 48RE 4x4 3500 3:73... Sounds like it could be the driving habits in my own opinion... . Please, NO flames

Im not sure How much driving style i really use with the cruise set at 70MPH I hold the wheel stright unless i have to turn then i move it a little.

No Flame intended LOL It really cant be the style I have driven all my truck in every way grandma to stole it. I can see 10 MPG driving 5 miles back and forth to work what im saying is on the highway it should do much better and it dont.

 

[SGBARRACUDA]

I can relay my experience. On my 03 3. 73 auto 4x4 3500 dually the best milage I ever got was 16. 0. Win I pulled my race car and 26' enclosed trailer it would get 10 -11. 5 depending on the terrain. A good average with that truck I would say would be 15- 15. 5, that was with the 250 hp diesel. I traded it for a 2500 4x4 3. 73 QC with the 325/600 and the best I've gotten is 21. 5 and a fair average is 19. 5. The dual rears seem to have a big inpact on milage.

 

[lmills]

Man Dave, that's as low as it comes. I hate to rub salt in a wound, but with the 03 dually that you saw at the dyno events, I got 18-19 on the highway. That was with a 6 speed of course, but still with the 4. 10's

 

[Disel Dave]

Man Dave, that's as low as it comes. I hate to rub salt in a wound, but with the 03 dually that you saw at the dyno events, I got 18-19 on the highway. That was with a 6 speed of course, but still with the 4. 10's

I was only kidding, I had may people say that same thing But Greg has road with me many times I drive like a sensable person and like there is a egg between my foot and the pedal And it dont seem to matter. I get bad MPG The only thing I have that does good is my KIA car LOL and it screems at 70MPH. Something is not right and you know me I will find it In time.

 

[lmills]

Ahh I know you were joking, I just can't get over the milage being that low.

 

[Disel Dave]

Ahh I know you were joking, I just can't get over the milage being that low.

Yeah me either.

Hey you have fuel pressure gauges, do you have before (lift pump pressure)cp3 and then a rail pressure gauge?

How high does the rail pressure get?

Im thinking about doing some fuel pressure gauges but for now im just going to do some test.

Dave

 

[lmills]

unless you are running a hotter box than you are currently, I wouldn't bother with checking rail pressures. They are over 20,000 psi and there aren't a lot of gauges on the market that will work in that range. You could look into a outlook monitor or a SPA gauge for the rail pressure if you really want to check it. As for the lift pump pressures, I check mine after the filter.

 

[Disel Dave]

unless you are running a hotter box than you are currently, I wouldn't bother with checking rail pressures. They are over 20,000 psi and there aren't a lot of gauges on the market that will work in that range. You could look into a outlook monitor or a SPA gauge for the rail pressure if you really want to check it. As for the lift pump pressures, I check mine after the filter.

I finally got the powerstroke van done I was working on in the shop, Had to reseal the pan and install a new rear main seal It only has 469K on it and still running strong.

so I pulled the dodge in and put in a new fuel filter, Looking at the way the fuel goes a restricted filter could cause a flow / pressure drop to the cp3 pump. it seemed to run a little stronger after so we will see I'll try another tank of fuel if the MPG don't come up I'll check lift pump pressure at full load.

 

[SBurton]

Nothing to worry about. Mine do's the same thing. We just have to live with it.

 

[Disel Dave]

Nothing to worry about. Mine do's the same thing. We just have to live with it.

No sure Im following what you are saying, you mean you truck is getting Bad MPG?? Like Mine

 

[Disel Dave]

any one know If the lift pump is covered under warranty and if so what one?

 

[swexlin]

Dave, lift pump should be covered under 100K engine warranty. Are you sure your lift pump is bad?

 

[Disel Dave]

Dave, lift pump should be covered under 100K engine warranty. Are you sure your lift pump is bad?

I put a gauge on it It holds 7 PSI most of the time it will hold 7-5 psi at a cruise 1500 rpm

If i go to 2000 rpm up a slight hill it drops to 2 psi and if i tromp on it at 3000RPM it will drop to 0 psi untill i lift off the go pedal.

at 0 it is starving the PC3.

I seen a post some where that it should hold 5 psi at a min at WOT full load.



If you are in the area some time stop by we can put the gauge on yours and see what it does.

 

[lmills]

sounds like it is time for a lift pump. good luck convincing the dealer though.

 

[93 Dually]

Hey dave i dont have a 600 im a first generation owner but my dads 600 get 22 mpg to 24 mpg bone stock is yours stick or automatic he has the six speed sounds like you got a problem 10 is really bad my truck get 21 and 18 in town

 

[2Gen3Gen]

any one know If the lift pump is covered under warranty and if so what one?

Wow, I keep returning to this thread. Just my own opinion, I would go for a lemmon law buy back or unload that truck and start over. It seems to have quite a bit wrong with it. Life is just too short to be spending it trying to get a $40+k truck to run correctly when it is not that old. If I were in your shoes with the luck you seem to be having, my next truck would be a lease. Then you can just give it back when you are not happy with it.

 

[swexlin]

If you are in the area some time stop by we can put the gauge on yours and see what it does

Dave, I might take you up on that. My truck is going in on Tuesday for warranty replacement on my leaky CP3 injection pump. My truck has only 19,000 miles. I would be interested to know what my lift pump is doing; i. e. id my lift pump starving the CP3, which caused it to go bad?

good luck convincing the dealer though

I concur. My dealer insisted there was nothing leaking under the truck (even though the spot is quite visible on the ground). I had to take the tech and service manager UNDER the truck, and point to the drip coming off the wiring harness. ONLY then did they call STAR, and get authorization to replace the pump.

 

[Disel Dave]

Wow, I keep returning to this thread. Just my own opinion, I would go for a lemmon law buy back or unload that truck and start over. It seems to have quite a bit wrong with it. Life is just too short to be spending it trying to get a $40+k truck to run correctly when it is not that old. If I were in your shoes with the luck you seem to be having, my next truck would be a lease. Then you can just give it back when you are not happy with it.

Well I bought it used Im the 2nd owner I think they may have did just that unload it and was the one who bought it LOL

It only has one Issue BAD BAD MPG If i get that worked out IT will be great.

I had a powerstroke before im use to little problems, I mastered powerstroke repair so now it is time to master cummins CR repair I just filled up i towed 34 miles out of the 248. 3 that was on this tank the rest were in town no real highway to speak of it took 29 gal I went with 28 when I hand calculated it because last week the man who filled it I don't feel got it all the way in the neck. so at 28 gal and 248. 3 Miles = a wopping 8. 867 :--)

wow