Hello all,
I have a 1992 F-250 SuperCab with the injected 460 and the e4od trans and 4WD.
I am getting an honest 5.5-6 MPG. The truck starts and runs fine. I have replaced plugs, wires, cap and rotor, air filter, synthetic oil and filter, set the timing at 12 degrees and put a free flowing exhaust on the truck with an empty cat. Gets the same mileage that it got before I did all of this. There is no gas leak. There is no cloud of black smoke, the tailpipe is not all sooty. The only odd thing is the smell of anti freeze after i drive and park it. It doesn't run hot and I have not had to add anti freeze. There is no mechanical drag that I can see. There is not a stuck brake. It doesn't care if I am in 4WD or not. I can haul 5-6 thousand pounds in the back and it pulls very good.
I have had GM trucks with the 454, carbureated, and no overdrive, and
4.10 gears and gotten an average of 9 MPG.
I don't know what else to do to this thing. I could blame the O2 sensor, but you would think that there would have to be a very noticeable richness to the exhaust.
Any ideas??

 

I wish I could give you advice, I have an 89 with a 460 and a C6 that was getting horrible mileage and basically I did all that you have done, and mine is getting around 12-13 highway, of course this is with a 3.55 gear ratio and keeping it under 70.
I would ask a couple things that you didnt appear to touch on. I didnt catch if this was in town mileage or highway. Also, how long have you had the truck? Also, does it have the stock size tires on it according to the door tag?
The first question is obvious, in town mileage sucks and highway mileage sucks a little less with the 460 Ford. I ask how long you have had the truck because if you had just bought it, the gas you buy in the winter is mixed differently than is summer gas, you wont get as good of fuel economy, also the 10% ethanol gas isnt helping any vehicle these days, regardless of what motor you have. The last question, if you have larger tires on, your odometer is going to be off and so it your calculations for checking your mileage.
These trucks will get pretty descent mileage, I had a 97 1 ton 4x4 crew cab chevy with a 454 and 4.10 gears that never got better than 10 mpg, so the fact that my 89 F250 460 with a 3 speed gets 12-13 I am pleased with, plus I feel that the 460 pulls way better than the chevy competitor, but I have always been a Ford guy.

 

Howdy,
Good questions.
It is an average of both town and highway. I drive it like a little old lady, and i have also driven it fairly hard, doesn't seem t matter a whole lot. The tires are stock size and new. The odo is dead on with my 2001 Olds aurora on my work commute. I've had it since last fall, so it has seen warm and cold weather.
I cannot fathom pushing this much fuel through an engine that really isn't working all that hard. I mean it's fuel injected and has overdrive for Pete's sake. I've worked on cars as a hobby for 25 years, and the only other vehicle that I had that got this bad of mileage was my 450HP ( no nitrous) Camaro with 4.56 gears and a TH400. I have never owned a Ford Truck before, I have probably had 10-12 GM trucks but I like it quite a lot except for the horrendous fuel economy. It is a hauling monster for firewood.Better than any 3/4 ton Chevy I've had. I have looked and smelled for a fuel leak and I cannot find one. You can watch the freaking gas gage move as you're going down the road. Ticks me off I can't get it any better.

 

well I have never had it happen to me personally but I have read on here where if you had 2 tanks that it is possible for one to be cross feeding into the other tank. That could possibly be what your experiencing. This is a great place to get ideas for what goes on with your truck, guys in here have helped me numerous times. I would check the cross flow issue and maybe you will get lucky.

 

I actually checked that as one of the first things, no dice.

 

Yes your odometer will be running slow with larger tires, your mpg is probably quite a bit better. 10-11 is about right for a 460, 8-9 mpg not uncommon.
Try checking a GPS against your odometer to see how slow it is.
Have you checked for codes yet?

 

There was a guy lately having bad mileage with his 460... here's the thread. Turned out his problem was a combination of O2 sensor and low tire pressure. You might want to read it... could very well be the same problem as you even though your exhaust doesn't seem gas-rich, you say? Are you completely sure?

(thread extracts below)

Link:

https://www.ford-trucks.com/forums/1...d-mileage.html

Original post:



Later in the thread:


Good luck! Keep us informed!

 

Old93, As I said before, the tires are Stock size and new , and the Odometer is dead on with my 2001 Aurora. Also with my Toyota van for that matter.
I run 65-70 psi in my tires. I haven't put a code reader on it, but the CE light isn't lit after starting.

Lio45, I am not absolutely sure that the o2 sensor isn't bad, I have not checked it with a meter, but there are no signs of running rich. I should check it just to rule it out I suppose. I haven't checked the TPS either, but the truck really does run just fine.

 

Just because the CEL is not on does not mean there are no stored codes, throw a code reader on it anyway.

 

93,
Yeah I guess I'm down to that. I don't have one, but I think I can get ahold of one. I could count the blinks, but i really hate doing that. I haven't had that much luck with code readers, usually they throw a ton of codes blaming everything but the power steering pump

 

[QUOTE=Django92;9815437]Hello all,
I have a 1992 F-250 SuperCab with the injected 460 and the e4od trans and 4WD.
I am getting an honest 5.5-6 MPG. The truck starts and runs fine.

I will tell you what's wrong if you promise to pay for a few lap dances and beer for me at the boobie bar? It is good news by the way. Under $20. Change the PCV and see if it don't make you smile and your heart calm the *** down. LOL. Send payment to: PayPal.Me/deankoch46 It's got to be worth a hundred bucks huh?

 

I had a 1 ton motor home with a 460 in it. Loaded with all the camping stuff it only would do 6 to 8 mpg. It was like a mortgage payment to fill it.

 

[QUOTE=deankoch46;15873173]Easy now...


OP,
Is your trans in good shape? Is the motor getting up to operating temp?

 

[QUOTE=mountain dewd;15873277]

If you think it's my truck it isn't.

 

Nope, thats why I separated my two blocks of text and readdressed the OP.