Installed a CAI and Cat-Back Exhaust on a 18' JLU Sahara and lost 2mpg

[bcupton]

Hi,
I gave my 18' JLU Sahara a couple of Christmas presents: A cold air intake & a cat-back exhaust. Now I've lost 2mpg and I was told I need a Tuner. Any suggestions? Yes, it sounds great but I really didn't want to lose gas mileage.

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[nyvisual]

Well you increased performance which inversely crashed your MPG. You don’t buy a Jeep to worry about MPG. Enjoy the few gains you’ve added, and don’t stress about to 2 MPG.

Have you pulled any fuses to reset the computer? I’m also thinking the computer hasn’t recognized the changes. I could and am probably wrong, but it's worth considering.

 

[bcupton]

Good point! What fuses? How would I reset the computer? I use a Tazer JL Mini to tweak a few things...but it has no effect on the internal workings of the engine. Thanks again!

 

[AFD]

Not sure about the Pentastar, but in the past I've noticed freer-flowing aftermarket intakes (whether drop-in, open-air, etc) tend to drop your fuel economy slightly at first, but after a few months of getting dirty and letting the ECU adjust, my mpg always seems to go back to normal and eventually does a few mpg better than before installing.

Not sure how accurate it is, but I remember reading K&N posting something about the minor dirt/dust accumulation somehow better funneling the air into the intake. I'm also guessing that an initial drop in fuel economy is partly due to lead-foot (listening for added 'swoosh' noises or checking for any minor performance gains) and partly due to the ECU adjusting for any air flow differences (disconnecting/reconnecting the battery might speed this process up). An immediate ECU tune would probably correct this, but is likely unnecessary if keeping the stock MAF housing diameter the same.

 

[BrntWS6]

Livernlos tune

 

[Kreepin1]

Livernlos tune

I'm pretty sure the Livernois tune is focused on power, not fuel economy.

I think if you disconnect the battery overnight the ECU will reset and begin to relearn.

 

[BrntWS6]

I'm pretty sure the Livernois tune is focused on power, not fuel economy.

I think if you disconnect the battery overnight the ECU will reset and begin to relearn.

I have had their tune for about a year. You get a power and mpg benefit. I personally gained 2 mpg. Their trans tune is great as well, makes 8th a more usable gear. It's expensive but any good tune is.

Resetting the system wont do anything.

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