improving fuel economey

[billk]

I have an 88 C2500 5.7 liter TBI with the 700 R4 tranny..
It has 148,000 miles on the clock
The cat has been removed and it has a single flow master into dual pipes.
I have owned it for about a month..I bought it in St Augustine FL and drove it home to Fort Lauderdale FL.
( approx 300miles) The truck ran nice and averaged about 14 mpg. Around town it has been getting about 11 mpg..I am about to take it on a 1500 mile trip to upstate NY and am trying to improve the MPG..
I am an old man and drive very conservatively ( well most of the time anyway)
I have installed a Jet stage 1 performance chip, a throttle body spacer, a injector spacer, changed all the fluids, new air filter, and new AC Delco plugs..
The exhaust "smells" like its running rich..I am thinking about changing the oxygen sensor but don't wish to if it's not needed.
Is there a simple way to test the O2 sensor?
Any other ideas that might help the MPG..if I could get 2 more mpg on a 1500 mile trip that would be quite a savings at 4.15+ per gal
Someone suggested plugging the egr valve but I don't understand how that would help improve the MPG
Thanks
Bill

[mudseeker]

you don't want to plug the EGR valve. the computer adjusts the air/fuel mixture to include some of those exhaust gases.

What is an EGR Valve - What Does My EGR Valve Do - Where is My EGR Valve

The EGR valve helps your car more efficiently and completely burn fuel by recirculating a portion of your exhaust and running it through the combustion process again. This results in a cooler, more complete burn of the fuel which decreases you car's noxious emissions by prohibiting the formation of some harmful gases.

have you noticed a change with your TB spacer?

the easiest way to improve mileage is to keep you tires inflated properly

[billk]

have you noticed a change with your TB spacer?

Actually no..it did not seem to help at all..nor did the jet chip..in town I am still getting about 11 mpg...I am hoping the highway mileage will improve...
I may just swap out the O2 sensor
Autozone has them for about 22 bucks..it can't hurt and might improve something..
Air pressure in the tires has been checked and is at factory specs.
I don't know where else to look to improve the MPG
Bill

[mudseeker]

forgot to mention in my previous post, but you may want to try cleaning the EGR. it could be restricted due to carbon build up and not allowing the engine to achieve a complete burn. (your rich smell)

the o2 sensor would be a good thing to look at also. it's kinda like a spark plug, you can tell by the color if it is still good or not.

[bradrhale]

being an 88, if the o2 is out, it should through a code. theoretically. also keep in mind that this is not a half ton pickup. you are not going to get absolutely great mileage with the 3/4 ton that you bought.
with late 80 model pickups, i have found from my experience that driving 5 and 10 mph less on the highway does help out.

[billk]

Thanks I realize it is a heavy truck and I don't expect to get 25mpg...I would be satisfied with 17 or 18 on the highway..I don't believe that is unrealistic..
I pulled the O2 sensor..it looked OK ( at least to me it did) but I bought and installed a new one anyway..If it helps at all it will be worth the 20 bucks it cost me..plus I know its new and not causing any problem
I took a pic of the old O2 sensor and attached it ..
I will pull the egr valve and clean it maybe that will help..
I'm sure something is amiss by the "smell" of the exhaust
The truck runs great I'm only attempting to save a few bucks on this 1500 mile trip..I'll try 70 mph on one tank, then 65 mph on the next and so on to see how it effects the mpg...anything below 55 gets you run over..
I suppose once I get far enough north cutting off the A/C will help some
But I have also read cutting off the a/c and rolling down the windows may make the mpg worse
Bill

[heavychevy85]

what gears are in it i don't know what gears they put in them but i got 3.08 gears and i get excellent gas millage so try droping a gear set or two it wont hurt since you only have 2wd

[mudseeker]

it doesn't look horrible but it looks like it has some build up on the lighter section.
like you said, worth the $20

[billk]

Someone changed the glove box liner at some point in time so the sticker with all the codes is missing..I have no idea what gears are in it..changing the gears could get pretty expensive..probably not worth the savings it might produce...
I bought this truck for my brother who lives in a rural area of upstate NY and he is driving a rust bucket..I am going up to help him repair his house and will give him this truck when we are finished with the repairs, then fly back to Florida in August...He has no idea I am going to give him this truck and will be thrilled as this truck has never been hit and has only a tiny tiny bit of surface rust on it..it is solid as a rock as it has always been an inland Florida truck...if he has it painted it will look new
It almost a shame to leave in in NY as 3 or 4 years on those salted roads will take its toll on it...oh well what can you do..

Bill

[bradrhale]

i agree about the 55. i never do 55 on any highway for fear of someone running me over. hope something works out in your favor though.