trying to improve fuel economy looking for any ideas

[mgm5555]

I have a 1988 ford 460 fuel injected c6 4wd 3.50 gears I am only getting maybe 7mpg with this truck which runs great. The cat was clogged so I knocked it out. truck has plenty of power, and i would like to keep it, but not sure if i can afford to. I am looking for cost effective ways to improve gas mileage. was wondering if i cut fuel to two cylinders if that might help and when i need the power turn them back on. lowering the fuel pressure in the rail changing the electronics so i cut the on time of the fuel injectors someone told me changing the torque converter to a lock up will help, not sure if that could be done? one would think there would be a way to make the gearing in the transfercase to have overdrive. I know most likely i cannot do anything to improve the milage except to buy a diesel, but look for ideas thanks

[hellraiser]

taller tires will probably be your biggest gain and less gear.....

[1pump]

You can get aftermarket overdrive units, but you can buy a lot of gas for what they cost. $$$$$

[DeenHylton]

For a 1988 EFI 460 your milage is way off. The first place I'd start is checking or replacing your sensors. They can be off a little and not show up on your "check engine" light. I replaced my O2 sensor, ACT sensor, and my ECT sensor when I first got my truck at 67,000 miles. My mileage went from 8 MPG up to 11.5 MPG (empty, two passengers). Thirty thousand miles later and after a gear swap from 3.50's to 4.10's I still average 11.0 MPG except when I'm towing. Deen

[mgm5555]

I check my o2 sensor its ok, the act and ect what are those? Have have a lot of electronic test equipment so maybe I can check those as well. thanks

[1pump]

ACT is air charge temp sensor, usually located in the upper plenum. Just remove it and give it a shot of carb cleaner. I don't know about the 460, but a lot of Fords have sensors downstream of the EGR and they get polluted quickly.

ECT? I'm assuming he means engine coolant temp sensor. The one that inputs to the ECM, not to the gauge. It's bigger than the sending unit for the gauge and has a beefier connector rather than just a single push-on lead.

[jbalestri]

Deen is right, your mileage is way off. I have a 1990 F250HD 4x4 460 5spd with 4.11 gears and get 12-13 mpg. There definetely is something amiss with the electronics or fuel supply.

I wouldn't spend a dime on mods 'till you get the mechanics squared away.

1990 F250HD 4x4 460 with 123000 mi

[mgm5555]

Ok if you guys think i should be getting 12 mpg or so I will have to try and figure this out. This ACT and ECT sensors, I poped open the hood and did not see any sensor around the air cleaner. But it was very cold out so didn;t spend to much time out there. I would like to know if anyone knows how to check these sensors, voltage out etc. I will have to make a trip intot he city and try and find detailed information on my truck.

thanks

[jbalestri]

About as much help I can be is to tell you to look in a Chilton's or Haynes manual. I don't know what the specs should be on these sensors and don't have my manual at work.

Also, you said that the O2 sensor is good, but until the computer gets a reading of a specific temp, it ignores the O2. If the computer nevers gets told that the engine is up to temp, it will never lean out. I think that comes from the ECT.

Sorry I can't be much more help.

[Old5]

MGM
Couple of things to consider for mileage

O2 sensor... May read properly on the annalog meter and not show a check engine light, but changing it will net mileage, not sure why, but I refused to believe it till I changed mine, bottom line it works

Plugs, wires, cap, rotor, timing. When was the last time these where changed/checked, 460 is notorious for eating plug wires, got about a year out of half decent set, changed to heavy duty Aurora set about a year ago still good. good plugs and proper gaps, timing etc

A good tune up will make the difference keep an eye/ear out for vacuum leaks, lots of little connections that can jiggle loose

Air filter stock replacements are cheap, K&N to fit the box is about $50 I got rid of the box and put in 2 Cone K&N, jury is out on this, sounds so good with your foot in it you will want to drive it harder thus not helping mileage

Thermostat, common trick is to put in a cooler 'stat, as it causes the computer to richen the mixture thinking the engine is cold, helps create more power, put in the proper 'stat to help mileage

Get rid of exterior junk(Aerodynamically speaking) hood deflecters especially the screw up the laminar flow the truck is designed to have along with roof deflectors fdast backs etc and a flow though gate helps if you don't have a canopy.

Canthelp with tranny tips I have a ZF and 3:55' in the back cruise is 2200 @ 65 mph

Good luck, the only way to get better mileage would be tradin'er in on a econo mini coffe can mufflered wanna be muscle car

Cheers

[Old5]

I forgot

Adjustable fuel pressure regulator, I haven't dabbled with mine because i converted to dual fuel a couple months ago and hardly use gas. There is an excelent write up in a 4x4 mag about 460's and mileage(Theirs was a dually crew cab) and theyed showed what pressuer netted the best mileage. the article is on the web and is referred to in this column several months back I believe "Four Wheeler" was the magazine. Friend in town put an adjaustable unit on his 302 and says it is worth it

Happy trails

[genspot]

Hi Guys,

I have an '88 F350 crew cab dually with a 460 and ZF five speed.

I've been playing around trying to increase the milage for some time.... Here's what I've done and the benifits gained.
Note that my fiqures are derived using Canadian (imperial) gallons so make the adjustment for US measure as needed.

as purchased:

Hwy milage empty ~15 at about 65 mph.
Hwy milage towing a 6,000 lb travel trailer ~8 to high 9's depending on terrain. (I live in B.C. so mountain passes are a fact of life)
around town milage was right around 10.


Modifications and results:

custom exhaust from the O2 sensor back. Twin hi-flow cats going into a single Flowmaster 70 series muffler with a single three inch pipe to the back. no change around town, picked up about 1/2 to 1 mpg towing.

K&N filter in the stock box. No measureable change.

Blocked EGR. No measureable change. (now re-enabled)

Straight up timing gears and new chain. Better driveability, very slight change (maybe) in MPG... will keep track and let the site know.

Home made cold air pack. Brand new, so no MPG data yet. BUT... this has let me advance the timing to 12 degrees and still run on Regular 87 octane, which it would not do even at 10 degrees before.

Blocked off Thottle body heater. part of the cold air experiment, so no real data yet.

My conclusions thus far.... expect only small gains, if any from modifications to the 460. I expect the biggest gain will be the ability to run regular gas instead of mid grade or premium. To this end I will be trying water injection next in order to permit towing on regular gas. stay tuned!

I should mention that the truck came to me with the air pump removed. With the mods mentioned above the truck passes our smog test with tons to spare. (our smog rules only care about the emissions, not if the factory equipment is still in place)

cheers!

Rob.

[mgm5555]

Thanks for that info, save me some time. First thats pretty good mileage to start with. the k&n filter i here helps only at max output of the engine where air flow is important. I like to here what results you get with your home made "air cooler"

water injection from what i have read may no increase miliage very much but will allow you to burn a lower octane and advance timing without knocking.

I am looking into shutting down a couple of injectors and maybe leaning out (shorten the on time of the injectors) to make some gains. The new truck prototypes at highway speeds shut down 4 cylinders and you cannot tell. of course I will notice since I cannot duplicate what the they did but something I will try.


Now if I check the O2 sensor and its giving me .5 volts and it is down stream as far as you can get does that not tell me the engine is running fine?

[genspot]

Regarding shutting down injectors.... I may be way off base here, but it seems to me that shutting down one or more injectors will result in the "dead" cylinders operating as simple air pumps.

The air from these cylinders will carry it's full charge of atmospheric oxygen which will be detected by the O2 sensor. The computer will have no way of knowing that the surplus of O2 is caused by off-line injectors and will assume that the mixure has drifted "lean". This will prompt the computer to increase the amount of fuel going into the "live" cylinders to compensate.

If you've taken four cylinders off line, you will suddenly have the four active injectors shooting twice as much fuel, the excess of which will burn in the headers and then the catalytic converter.

As I said, this is just the result of a "thought experiment" and is not based on any actual expertise in fuel injection... Good luck, and I'll let you know how the cold air pack worked out once I've run a couple of tanks.

Oh, I forgot to mention that I've also changed out the O2 sensor.. mine must have been good, 'cause there was no measurable difference in fuel economy after.

R.

[Old5]

MGM

Not sure how shutting down the injectors would work unlesse you could change the valve timing to lessen the effect of compression other wise you'll need power to compress the air in the cylinder(This is how a engine retarder works)
Unles you have a lot of time and computer program/ chip making experience or money I think it's a fruitless venture (Just my .02), let alone figuring out how to change the valve timing

Your O2 sensor should make sweeps as you idle or drive, this is the computer cycling rich and lean (0.5 seconds or less) thus creating a 'mean' stoich mixture if your's is not sweeping you may have something else going on (A digital meter will not read fast enough, you'll need an analog meter for this)

If you pursue the injector shutdown route, best of luck, sounds kind of like reinventing the wheel

Some of the older guys say not to cool the intake manifold as it makes it harder for the fuel to mix with the air make sure your egr is working maybe

Has anyone ever tested the nozzle spray pattern and if so what kind of set up did you use?