Recently purchased '89 F250 SC 4wd 7.3L Diesel 3 speed auto. I'm getting between 11 & 12MPG city no load. Does this seem normal? I've seen the thread here that lists mileage from about 10 to 20MPG, so this seems a bit low to me, but again maybe not since it's a 4WD, etc and no overdrive. Becaomes a fairly serious question because the damned fuel guages are unreliable like every ford built in 89.

While I'm at it, is this 3 speed tranny what you tekkies are calling a C6?

Thanks.

 

firts question find out what gears you have if you have 4.10's your proably pretty close normal.

 

90 250 4x4 s/c zf 5 3.55 no soup bowl kool blue filter 19-20 mpg mt

 

well, my old man's 84 6.9w C6 generally got around 12 all the time, less towing, it is 4x4 ext cab, 3.55 gears. My standard cab 4x with 6.9 and 4 speed 4.10 gets 13 normally, waiting to see if the better exhaust helps any.

 

The 3 speed auto is a C 6 that has a direst drive high gear.
To get good mileage on a direct drive transmission you need to keep your speed down to 50 or 60 MPH and take off from stops slowly.

I have a direct drive 4 speed 4x4 with 3.55 gears and a 70 MPH trip gets me about 10.5 MPG.
Same trip at 55 gets me about 13 MPG.
Also with all the stuff on my truck it weighs 7,860 pounds without me in it, so I am a lot heavier than most.

 

Well I Guess I'll try slowing down a bit. I do have the 3.55 rear end, and I have tried towing my Coleman Popup trailer (about 2500#). The trailer seems to make no difference in the fuel mileage. I guess the F250 doesn't know it's there.

I do live in hilly/mountainous terrain, and can't go anywhere but the 7-11 without either going up or down hill, so that probably has something to do with it alos.

Thanks.

 

Same here in WV, except the main road is on the other side of a hill from the house. Nowhere is flat anywhere near here.

 

I get about 19mpg with my '88 7.3 F250 4x4. It has the 5 speed (overdrive) manual and I drive about 60-65 on the highway (most of my driving).

 

That sucks that's all the mileage you get. My 86 250 IDI 2wd has 3.55s and C6 and I get an easy 18 on the highway at 65.

 

I have a 94 F250 4x4 supercab long bed with a IDI TD, E40D, 4.10 gears 235/85/16 tires at 80psi. The truck had 122k miles at the start of the trip and a bit over 123k at the end. I drove it back from FL and tested the mileage. Here is what I got...the truck was basically empty...one motorcycle in the bed and pulling a jetski on a trailer.

Cruise Controll set at 70mph (about 2250rpm) --> 13mpg

Cruise Controll set at 60mph (about 2000rpm) --> 16.5mpg

Cruise Controll set at 55mph (about 1800rpm) --> 21.3mpg

All of the above figures are indicated (as opposed to GPS confirmed etc) and were obtained in very similar moderately hilly conditions on the same day and were tested for more than 100 miles.

 

Man what this thread is telling me is that I need to get the RPMs down around 2100 or so for decent MPG. I think with the C6 I'm doing about 2700 @ 65mph! I'll have Yugos passing me at 2100 rpm.

 

I find that anything over 18-1900 rpms and my mileage drops off big time. A gear vendors would be very nice
I drove most of the way back [to va] from FL with the cruise controll set at 55mph, it took forever.

 

i get on average 15mph out of my 87 f350 6.9 4 speed, 4.10 gears, turned up pump, dual exhaust, no soup bowl.

 

I put a lot of stuff in mine though, I am happy with the mileage.

 

Gitterdun Dave! Even with a dinosaur of a rig.
What kind of dump bed do you have? I was going to put one on my 89 Dodge this winter.