Ok I am going to be realistic about my 258 80 CJ7 and say I would like to get the most out of the Gas I pump in. I live in TN and where I am at no emissions test. Soo...what can I do to bumb that magic number up as high as let say...16mpg. I am not even sure what I get now because my gas gauge us broke. But I can assure you that when I ran out of gas the other day a block from my house I was pretty
. I would also like to fix the gas gauge so I would at least know when to put more in. Now I am new at this stuff. I have put my 4" Suspension on, changed the radiator but when it comes to fuel lines, tanks, and emissions
Don't need a gas gauge to tell mileage... Just an ACCURATE speedo with odometer that works, and you have to remember to write down the number of gallons and mileage on the odometer each time you fill up...
If you have oversize tires, the speedo is going to read slow, and that is going to show less miles for the tank full of fuel, so an ACCURATE SPEEDOMETER IS MANDATORY!
You CAN use an inaccurate speedo to tell if you are getting more, or less, mileage than before if you run a baseline before you do the service work...
I know none of you wants to hear this, but take the big stinky tires off and put on stock size tires for better fuel mileage!
This will put your engine back into the RPM range it was set up and designed for, and it will give your engine/drive train a better mechanical advantage on the road for take offs and acceleration...
With taller than stock tires, it's like having the 'Over Drive' turned on all the time! It's lugging the engine in RPM ranges the Engine wasn't tuned to 'Lug' in...
Start with a full on 'Tune Up' & Full Service...
Service the differentials, check/pack the wheel bearings, service the transmission and T-case, Make sure the tires are aired up for highway use...
Get out the vacuum gauge and timing light, we gonna' party now!
Vacuum gauge will tell you if you are having problems with the engine,
Using a long hose and leaving the vacuum gauge in the cockpit is a good idea. A vacuum gauge will teach you how to drive your vehicle for economy (and lonjevity!) if you pay attention to it!
The higher the vacuum reading, the better fuel economy you are getting.
Do a THROUGH inspection of your ignition system...
If you haven't done the 'TeamRush' upgrade yet, DO IT!
Getting the spark to the plug at the right time means better fuel economy!
If the plug doesn't fire, you get ZIP in that cylinder!
If you haven't looked into changing your ignition advance curve yet, I'd look into that too.
Bumping up the ignition curve, especially when you are in lower gears and stop and go driving, will help with fuel economy...
(Pulling a trailer or extending highway speeds in top gear... Not so much...)
MAKE SURE YOU DON'T HAVE VACUUM LEAKS!
Vacuum leaks, like when the button valve in the EGR gets cocked sideways, are hateful to the carb's efficiency!
If you have a carb that has seen better days, REBUILD IT!
Kit's are about $20 and can be done in an afternoon easily!
Drooling, Dripping, Leaking carbs are murder on fuel mileage...
Make sure you use the vacuum gauge and TUNE YOUR CARB!
I gained almost 3 mpg just servicing the drive train!
I would have stood on a stack of bibles and swore that 'Lube Is Lube' and should make a difference, but the calculator don't lie!
2.85 MPG average increase over 3 months after a full dive line service!
Guess fresh lube is more 'Slickery'!