IndyL03

looking to increase mpg's. replaced fuel filter(WIX) after 3 seafoam treatments,replaced plugs in spring along with egr( ac delco), cap & rotor ( bwd pro), ignition module( AZ), O2 sensor ( delphi) , IAC(AZ), TPS(AZ), 195* thermostat(motoRad), repaired evap electrical, CTS ( BWD pro), wire set(AZ), knock sensor( standard),
replaced timing chain (cloyes).
having injectors serviced right now, fuel pressure is 13 psi steady, run bp and shell gasoline 87 octane.
tires 32 psi from Discount Tire setting. car is aligned but due for another soon. I have knn filter for stock air filter and spectre Cold air intake. thinking of going back to stock after reading info in fuel vapors burning more efficiently...
trans shfits firm; has 2month old fluid in it.
engine i run 10w30 mobile1 high mileage.
what else can i replcace to help boost mileage? mind you i am 93 caprice L03
also dynoMax muffler; resonator delete. thinking of upgrading to 3inch y-pipe and 3in & 2.5out cat or gut the one on now
suggestions?

shortyskater

Buy a hybrid

one92rs

iTrader: (5)

what is the mileage now?

UnderCover89TBI

iTrader: (25)

rear end gears if a lot of highway crusing want numerically lower #'s. 2.73's or so. You can make the car lighter which can help fuel mileage. a less restrictive exhaust helps fuel mileage. staying below 2500 rpms saves it too. really upshift points below 2400 rpms if you can. less rotational mass. you can install a smaller diamater crank balancer, aluminum pullies. Buy the EBL flash and tune the car some will help. But im wondering how much you really want to get. Oh and also if you have a Heated 02 sensor that will help get into closed loop faster which will burn less fuel.

IndyL03

I was looking into a heated O2 sensor... would help out in the winter i think along with my block heater. IDK what I am trying to get specifically, just trying to get more for my buck. went from 2.56 to 3.08s but having problems with vibrations at 60-65 mph. took shims out at tail shaft and did not help much. thinking of gettin new lower rear arms. milage is ~20mpg average with a little city and highway and a/c going. last year did 32 on 2.56 gear from indy to daytona beach and back. was considering headers and 3 in y pipe( as on 9c1 police package) and end up with 2.5 single after muffler.

IndyL03

was told to reinstall stock air intake to air charge heated for good mpgs

ex-x-fire

I used to have an S-10 w/ a 4.3L, I played around w/ getting good mpg. I found that a quick warm up really helps mpg esp. in the winter. You can bump the ignition timing (this helps make more vacuum that the map sensor likes), but bewhere of spark knock. I also ran a 205* stat & eldelbrock water pump year round. The pump was alot lighter then the oem one, & I think it helped w/ the spark knock. It had a much greater flow rate then the stocker.

IndyL03

how r u doing a quickk warm up. i use block heater in winter but idk what to do for summer. i let the car run for a few minutes and head out

IndyL03

just had my fuel metering reconditioned, flow tested, and visual atomization inspected- this had the most improvement along with swapping to the delphi oxygen sensor from bosch.

trying to test coil but keep getting shocked from using cheap tester-might have failure on horizon since it is the original one. will be replaced later today for g.p.

fuel pressure was fine last time i checked 13psi steady where it should. will check again

MAP matched ambient air pressure-have next test while running under vacuum.

had laptop connected and BLM was at 128 but INT was 125-127 so i take that as being rich and ECM is trying to lean out fuel mixture??
the IAT seemed low to me though was at ~70 but i thought the preheater should make it higher as it reaches closed loop and thermostat opens?

is the anything i am over looking?

IndyL03

Ran a trip on highway a few weeks back and did a scan and the long term was 127 and short term was 125- i might have these numbers reversed but i got 28 mpg est and was in cruise @ 75-80 mph, shell and bp gas, 3.08 gears, and 235/75/15's in back. so i think thats acceptable- not as good as the 32 mpg i got on the trip to daytona but i was 2.56 then. but i did notice that tps would glitch a little. when throttle is closed it should not have any variance in reading and it does so I 'm going to order ac delco for that or use BWD from o'rielly. I had to use the autozone one when the other tps went out since it was there but i feel that the product was sub-par and giving erroneous data. I get variances at closed and WOT .

IndyL03

does the pick up coil ever go out or have any effect on things? idk if i'd mess with it but only test i see is for resistance and it was in tolerance. but i dont think i'd mess with it tho- would rather take and get another distributor and new pick up and module would be included

Ron_90

There's an "edit" button you can use if you want to say more in your post.. easier to follow than reading multiple posts.

Your mileage is pretty damn good though. My dad's '02 Honda Accord V6 gets about 20-22 average and my grandfather's '10 Accord I4 is only slightly better than that. I wouldn't try too hard to improve MPG's or you might screw up what really works now. Not to mention, your car weighs 2 tons lol

IndyL03

yeah car has some weight. I took my speaker box out. been running 33 psi in tires. still need to install new TPS sensor. but i did take a trip from Indy to Chattanooga and made it there and drove around 3 days on about 50 dollars. I put car in cruise just a little faster than what the semis were doing. and was stuck in traffic for 30 minutes. hope to keep the same or better on my trip from Indy to Ft Lauderdale.

BlackenedBird

iTrader: (5)

You could try a synthetic and/or lower weight oil for less rotational frictional weight.

And check out http://www.fuelly.com for ease of tracking & what others are getting. As well as seeing what others have done & works & doesn't work. I've seen some dumb suggestions over there that MIGHT get you 0.0001% improvement, so it is a matter of wading through there to find some to try.

My TPI 350 best is 21.1 & my overall average is currently at 14.4, but that is because of a bad MAF I just replaced so the bad overall average is still calculated with those # & low as a result. I'm running a tank average of 16.7 on my 350 TPI right now.

IndyL03

That trip went very well. changed oil-M1 10w-30 high mileage, changed trans fluid- castrol, replaced steering gear, power steering cooler, and greased steering linkage. drove over night. I minimally went speed limit or drafted whatever someone was going. Averaged ~31mpg driving on highway a/c on during day time. ~18 driving around town.

on 2nd tank almost went 800 miles

Beef

iTrader: (1)

I'm kinda confused, you want fuel economy but put in significantly lower gears? That's generally only mpg advantageous if you're lugging the motor constantly. You are doing pretty good out of a big and heavy V8 car though. If primarily highway maybe aerodynamics? get it lower, and/or lower rolling resistance tires. Syn fluids for the gears, syn grease on the bearings. Does the caprice have electric fans? Faster warm up, add a 110V oil pan heater for the winter too.