Engine/Transmission (1994 - 1998) Bad Fuel Economy on 98 215HP

[ctdf]

Just bought a 98 3500 dually 4x4 5sp quad 3. 54 limited with 198,000miles,on the way home I was towing a 22ft bumper hitch with a 99 crewcab Ford 4x4 PS, took brothers truck and trailer to get it. I wanted to see how it pulled so we loaded his on the trailer and headed home, we left Castle Rock, CO and drove to Goodland, KS and filled up, 8MPG :{ :{ :{ ,so we switched and drove to Salina, KS and he filled up, 8MPG :{ , but I felt better, so we parted ways, he lives near Witchita, I got in the Dodge with his trailer and loaded my festiva on it, I know, BIG TRUCK, little car, and headed for N. E. Missouri, stopped east of ST. Joe, MO still ONLY 8MPG :--) Filled up after getting rid of car and trailer and drove around here for a week and light go pedal and check it by itself, 10. 5MPG This truck is bone stock, no pump tweaks, turbos, still found that cat under there, THOSE WONT LAST LONG, but my main question why the bad mileage.

The two trucks and trailer weight about 20-21000, truck, trailer and car about 12500-13000 and the truck with the flatbed on it 7840, bed is for sale, I know this is not normal, I have an 84 Ford with a 180 hp #6plate cummins motor 5sp 4x4 extended cab 3. 54, they weight the same, with this combo got 18-21 empty, 12-16 with the 20000 or higher weight, put 215 injectors in, didnt hurt, then put 215 pump on and timed to 16btdc, dropped to 15-16 empty 10-12 loaded 20plus weight, #10 plate Oo. , same mileage, again any thing to help my mileage Thanks Chris



P. S I thought 215 pumps were better on mileage I had 2 and both have done worse, my bad luck or what?

 

[Neibe]

The worst mileage I ever got was 10 pulling 10,000lb fifth wheel into a stiff head wind going 70-75 in some pretty hilly area. Do you have a leak when was the fuel filter changed?

 

[McCRam]

My mileage came up about 5 mpg when I changed the first filter on my truck, maybe thats it. Other than that, check the fuel pressure, check the filters and fuel screen. Good luck.

 

[nfox]

Poor Mileage

I would suggest checking the fuel pressure and check the injection pump timing to make sure its at 16*, if the timing slipped you get get really poor mileage. When you start it in the morning does it miss, when the oil pressure comes up try to accelerate the motor to 1600 rpm to see if it misses or smokes white.

 

[AfterBurner]

Check all your boost lines and clamps, to ensure you don't have a boost leak anywhere.

When it goes "naturally aspirated" it will suck the deisel!

 

[DPinkston]

Have the timing checked as mentioned previously and get a new overflow valve for it. Is the speedometer registering correctly? If it's slow you are losing miles there. May be several things together that are causing your atrocious mileage.

Danny

 

[ctdf]

I haven't change the fuel filter, checked timing or pressure yet on the dodge, did them on the ford cummins, only had the dodge for two weeks, Im ordering a pdr hybrid hx35 and overflow valve next week and will change fuel filter, front main seal, kdp and timing, change to 60lb springs, for the exhaust brake, and check valve lash. Im thinking of doing the 3000 rpm spring kit Oo. , any thoughts? Also got an #11 plate for the dodge. Don't think I have any boost leaks, not positive and it smokes less than my ford cummins at the same temp and doesnt seem to have a miss.

What kind of mileage are similar trucks getting?

P. S Where is the fuel screen on these, is it in the fuel heater? I bypass the heater on the ford.

 

[Neibe]

I get 19 in the summer non towing 15 towing. See my sig above got 4:10. gearsThe screen is in the lift pump it is on the same side as the fuel pump but just below the pump on the block. It is right next to the primer bulb if I remember correctly.

 

[Got Smoke?]

My first thoughts are the CAT since you said its still on there, then fuel filter, timing, and check your intercooler boots. I've had intercooler boot problems on two trucks now and both times the mileage dropped 2-4mpg. You might just want to go ahead and order a PDR intercooler boot kit while your ordering everything else from him. Also, definately get the 3K kit you will love it while towing.

 

[AMcKee]

Mine is 4x4 and I get 17-18mpg empty. I definately second the motion on the 3kgsk.



Andy

 

[RBrunson]

My truck is about the same as yours with 105,000mi. on it, I got 13mpg with 5er in tow, 20,000lbs total. Running empty right at 18mpg. I haven't bumped up the timing yet, that should help some. Definetly get the 3K spring kit. You should be able to get the milage up after you go through the items mentioned above by others.