I tow with a 1989 F250 460 EFI, C-6, 3:55 gearing.
The truck only gets 4.5 MPG towing 9,000 lbs. and will drop to 40MPH in 2nd gear when pulling a grade. I have had a diagnostic check, changed the O-2 sensor, replaced the "cat", and replaced the plugs-cap-and rotor. The truck seems to consistently run rich as the plugs are black and the tail pipe is black also. I only get about 8 MPG when not towing. I have ordered Fords book on "Modifying/repairing the EFI system". Has any one had similar problems and does anyone know of a turbo kit to fit an "89" F250?

 

Concerning the rich fuel condition,I would change the coolant temp. sensor as you might already know that its job is for the computer to adjust fuel delivery according to engine temperature,cold = richer,hot = leaner,along with other emission functions.Hopefully this will get you better mileage/performance with little expense.Just because the sensor does not come up as a code doesn't mean its calibration is correct!
Phillip

 

You are running very high gears for towing 9000lbs.I have a 91 F250 4x4 with 460 that I used for hauling my 5th wheel for years.I have 4.10:1 gears and before I went to 36" tires it pulled very well.You more than likely have the Sterling 10.25 rear axle and there are many gearing options available for that axle(down to at least 4.56:1 ratio).No one as far as I know has a turbo for the 460 (I know Banks doesnt have one). There are superchargers available Vortech and Kenne Bell both make one.I am currently running the Kenne Bell which is actualy a modified Whipple Charger.You can also try a better air filter such as a K&N,better exhaust sytem(which you will need anyway if you go to a Turbo or Super charger).The stock aspiration on the 460s are terribly inadequate. And even modified computer Chips,the verdict seems to still be out on those,I was running a Hypertech Chip(with limited improvement). If you really want to run a supercharger you are probably looking at spending at least $5000.00 by the time you install headers. They do perform well though,I am currently running over 400 hp and over 500 ft/lbs of torque. Beware though Modified Motors tend to seek out the weak links in your drive train,usualy with catastrophic results. I would suggest re gearing the axle as your first step for more effecient towing.
Jeff
super@sierratel.com

 

>I tow with a 1989 F250 460
>EFI, C-6, 3:55 gearing. The truck
>only gets 4.5 MPG towing 9,000
>lbs. and will drop to 40MPH
>in 2nd gear when pulling a
>grade. I have had a diagnostic
>check, changed the O-2 sensor, replaced
>the "cat", and replaced the plugs-cap-and
>rotor. The truck seems to consistently
>run rich as the plugs are
>black and the tail pipe is
>black also. I only get about
>8 MPG when not towing. I
>have ordered Fords book on "Modifying/repairing
>the EFI system". Has any one
>had similar problems and does anyone
>know of a turbo kit to
>fit an "89" F250?

Phillip, hey where is the sensor located at? According to the Haynes Manual, it is next to the distributor. Is that right? I have removed the throttle body hose yet to take a good look.

 

That location sounds like a good place to look first.Far sure it will be mounted in a water jacket or thermostat housing on the intake.Purchase the new one first for a comparision.
Phillip

 

Phillip, thanks for the reply. I have a new temp sensor and will install this week. I'm towing my car hauler back over the mountain this weekend and should see if this is the "cure" for my overly rich condition and poor fuel milage.

 

Want to thank you also for replying. I have not found a turbo either but have found a company that will sell a "Vortech" for $2,800 but claim only 80 H.P. with 5 lbs. of boost. They tell me no higher boost without changing injectors. Did you have to change exhaust, how'd yours work with the stock computor...any problems? Also has any one tried "Banks" "Power Pack" they claim 70 H.P. for $1,600.? I'm trying to find the most bang for the buck. I will cost out the gearing but I do not have overdrive and am a little leering of going too steep in gear ratio for highway use. Thanks again.

 

The Vortech at $2800 is a good deal,the cheapest i found it fro when I was pricing was about $3000.Iwould say you will get more than 80 HP figure about 40 to 45% of 240 hp puts you closer to 100 hp,but you do need to use headers,I went with Doug Thorleys. I am only running 6lbs of boost with no injector mods.With the Kenne Bell Supercharger there are no new computer chips or anything but there are a few modifications and adjustments.I actually had a tech from Whipple install it since I am working close to Fresno Ca,where they manufacture them,(It seems like everyone into performance engines around here has worked there at one time or another). All of your base line adjustments for the fuel and idle and such have to be right on the money before they start tweaking it. if you let me know what size tires you have I can tell you your RPM range with the different Ring and pinions.When I was towing the trailer,with 4.10:1 gear ratio I never used OD (E4OD tranny)and it was always very strong but never over 3700 RPM for any sustained time.Occasionaly 4000 RPM in 2nd gear to maintain speed on a steeep grade.I would get about 7 or 8 MPG towing,(never below 7). The banks set up is a very good set up,we have a one installed on a work truck,Its basicly just a high volume air intake and headers and cat-back exhaust all worked into one well engineered package,You can get the same results putting on Thorley headers($650),a mandrell bent 3" Cat back exhaust with hihg flow muffler($250),and a K&N Filter($50).I actually dont even run a muffler anymore the catalytic converter has all the back pressure you need with the Thorley Tri Y Headers. Good luck
Jeff,
super@sierratel.com

 

>That location sounds like a good place
>to look first.Far sure it will
>be mounted in a water jacket
>or thermostat housing on the intake.Purchase
>the new one first for a
>comparision. Phillip

Ya got the sensor put in this afternoon. It cost me 12.76. It bubbled a little antifreeze when I put it in. what are some noticeable things to look for?

 

I have an '89 F250 4wd. It also has the 460, C6. Mine has 4:10 gears. Our trucks are VERY heavy. Add on a trailer (mine's an 8000 lb. camper) and you're pushing the design limits of the truck. I too thought that 460 should pull just about anything I hook to it...

Do the obvious.. CHECK COMPRESSION FIRST (mine had a nearly dead cylinder and I never felt a miss!! These engines are famous for having the wrist pins seize up and then the rings will start to break up. Find out about the rich thing... your plugs really should look good... not black or wet.

Mine too, bogs on hills.... and my gas mileage when towing my RV on a flat interstate with no hills is only 6 - 6.5 mpg!

I have 33x12.50x16 tires on it. My mileage figures INCLUDE compensating for speedometer error. If you're running anything other than stock size tires, calculate your speedo error.

Other than what appears to be a rich condition, your truck is doing what any other would when hauling that much weight.

Think long and hard about expensive changes.. they may not do what you want...

I've noticed that guys pulling similar loads as me blow my doors off going up hill when they've got the power stroke deisel... If you really want a torque monster that'll get 15 mgp towing.. trade on a good used powerstroke.

I know a few people that own 'em and love 'em.

Dave

 

 

Ivde got a 96 F350 with a efi 460 and I only get 7mpg no load its just a pig

 

WOW!!!!! A 13 1/6 year old thread!!!! Talk about a thread revival.....

 

Dude, thread is from 1999, I didn't know this forum existed then. How did you find this?
-Mike

EDIT: Darn, beat me to it.

 

Yeah I would have guessed we were still on the old email list in '99.

I put a 460 in my F150 and it isn't nearly as strong as I was anticipating. I hope to add Thorley headers one day but they are spendy. I get about 11mpg empty, so it's not as bad on gas as some others.