Tune up. If you have an O2 sensor (I think 88 has them) replace it, they are a big MPG killer.

EGR valve, clean or replace.

Keep rpms down.

I am afraid you won't get more than 1 or 2 mpg anyway. If mixed with city, that's good mileage . I know all of my vehicles really drop their mpg in the city.

 

my dads 94 got about 19-21 untill it got a little past 200,000
last recorded bout 16 at around 28?,000 when the timing chain jumped a gear. all it had was a filter, we upped the pressure in the tires 5 over, and it had some little bottle that slowly fed it some kind of cleaner,oh, and we kept it maintained like clockwork- which I think that that was what kept it so good, but it also saw 90% highway miles. but i think that an exaust system would be the best- fords exaust just sucked.

 

And don't forget to park at the same pump and at the same spot - the way the truck sits effects the amount of fuel it takes.

I agree with everything your saying TorqueKing. (And I've checked my odometer against the mile marker posts as you described.)

I calculate my fuel mileage for every three month period (i.e, Jan thru Mar, Apr thru Jun, Jly thru Spt, and Oct thr Dec and Yr to date) as the temperature has a big effect on fuel efficency. Plus figuring fuel mileage over 10 or 12 fill-ups minimizes the inability to fill the tank to the exact same level each fill-up.

Of couse, I understand that some think I've got too much time on my hands, but if your gonna figure your fuel mileage, you might just as well figure it right! Right?

 

Jim, I totally agree. What good does a junk number do anybody? Seriously, it takes me about the same amount of time as everybody else does to do my milage. While the truck is filling at the pump, I whip out the clipboard from the toolbox, and write down a few notes. 45 seconds tops. Once I've filled the clipboard all the way out, I take it to my computer and enter the numbers in an excell spreadsheet, and BOOM, I have a whole bunch of useful data.

 

If you got a manual trans, keep those rpm's down, lol yeah right

 

My 88 F150 5.0 4x4 gets 12mpg... and that was after a tune up!

 

Tune up. If you have an O2 sensor (I think 88 has them) replace it, they are a big MPG killer.

Question: How can I replace these sensors, and how expensive would that be? Also, where ccan I find a replacement? Please email information to Grammardan@aol.com. I don't get on here much. Thanks...

 

where is the egr valve anyway and what does it do?

Clueless

 

EGR valve.

It is usually mounted on the intake manifold and it is usually controlled by a vacuum line.

What does it do. Short answer; it reduces the amount of an air pollutant that the engine normally makes. The air pollutant is a combination of Nitrogen and Oxygen (NOx), an accidental by-product that forms during combustion. You can see this particular air pollutant in Los Angeles. It's the brown color in the air.

How does EGR reduce NOx formation? By reducing the temperature in the combustion chamber during combustion. NOx formation requires high temperatures. By adding extra air into the combustion chamber, air that has no Oxygen, the heat of combustion is spread out over more air and the average temperature is reduced.

Many people, including most mechanics, believe that EGR is an attempt to re-burn exhaust fumes, as if you could do better the second time. Right.

A side-effect of adding EGR to the engine is that it raises the part throttle compression pressure; more air in the combustion chamber means higher pressures at TDC. This make more power for a given amount of fuel. And that means you can use less throttle to get the amount of power you need to cruise down the road. Better gas mileage.

Another side-effect is cooler temperatures in the engine and exhaust.

EGR is closed at full throttle to help maximize the power potential of the engine.

According to an engineer I had a chat with on alt.rec.autos.misc the typical amount of EGR dilution is about 10%. He said that an engine can run into the low 20's but above that it is hard to sustain the combustion when the dilution gets above that.

I'll bet that was more than you were expecting to learn.

 

You said that the extra air, minus oxygen, is put into the combustion chamber to cool the combustion process. Does the EGR valve filter out the oxygen? If it does, it seems to me that this would lessen the efficiency of the combustion process since oxygen and fuel are the two essentials for combustion. The reason why you have to increase you air to fuel ratio when in high altitudes. The air is alot thinner.

Help me understand
Scott

 

Think of it this way: The EGR lets some exhaust into the intake tract. THis inert gas displaces some of the fuel/air mixture. When the inert gasses/fuel/air mixture enter the combustion chamber, the inert gas is not involved in the combustion process, so its sorta like having a smaller displacement engine becasue a smaller amount of fuel/air are consumed. This is not a problem when you are at light cruise. As you get into the throttle, the EGR valve is turned off.

If you want to see just how this works, T a vacuum gauge into the line that goes to the EGR valve and put the gauge in the cab where you can see it while driving. The slightest amount of throttle tip-in will turn the vacuum off.

 

so what if we found a way to turn the egr on/off/auto- and maybe get better gas mileage and more power?

 

"Light foot on the gas pedal" says it all Jim haha....I have a '90 F-150 5.0 5spd tranny, with a towing pkg, so the rear end it more beefy, and my gas mileage sucks....i get like 11 or 13 mpg, that is if my dang size 13 shoe isnt pushing it to the floor.....but hey whadda you expect, i have loud exhaust on it, so i have to rev it up! lol that is until i run outta gas

 

But that's just what she does now. EGR doesn't (or shouldn't) flow at idle, not at just off idle, not at heavy throttle, and not at WOT.

Only when you are crusing along and not using much throttle will the EGR activate. This is controlled by the point in the carburetor's venturi where the EGR's vacuum is sourced. (You wanna be sure that the EGR vacuum line is connected to the correct port on the carb.) When the EGR is avtivated it lowers the combustion temp to minimize NOX formation and slightly reduces the amount of fuel/air being consumed. But if you begin to squeeze down on the throttle, or back outta the throttle, EGR shuts down.

A well tuned distributor has quite a bit of timing advance built into it at light to moderate cruise because the combination of EGR (inert gases) + air/fuel needs more time to burn and you need to complete the combustion process by about 23 degrees ATDC to maintain reasonable power AND fuel mileage. Thats also why EGR equipped engines are very prone to serious pinging if the EGR valve fails (or is blocked off, or the internal passages become plugged with carbon deposits.)

Again, I suggest Tee'ing a vacuum gauge into the EGR vacuum line and see just how automatically the EGR is turned on and off.

 

yeah your getting just the right amount of mpg you would be lucky if you get up to 16. the only thing to do is to keep off the pedal and coast alot. but if you want to spend money you can put a eletric fan in and if you have power steering get rid of it no one needs it (haha) no but if you just had the alt. running on there it would help a little maybe an extra 4 mpg or more