sizematters11

Anyone have any if so which should I go with and how do you like it ????

sizematters11

Anyone ???

Mendax13

from what i understand... programmers dont work that great on the 4.0... and you most likely wont notice a change.

stereodesigner

dont waste your money

gvns8

x2

xjsnake

x3

Best gas gas mileage improver is your right foot unfortunately...

gvns8

Get a bored throttle body if you want actual cheap improvement on throttle response. As far as fuel economy- do a full tune up instead of buying the tuner to get better results.

sizematters11

Well damn looks like I'm doin a tune up . I seen a couple Programers in quadratec but they seemed kinda sketchy I've seen Programers do great jobs on my buddy's cummins and another buddys Mazda just was curious on how it would do the the good ol jeep lol

sizematters11

Haha I've already done that and it only works for soo long

bigvig

No good on our 4.0's. Like someone else said, do a tune up, and do it every 20K. For the $50 dollar tag, you cant beat it. And while youre on that, do ALL the fluids and filters (oil, trany, trans, diffs, etc.). Also a bored throttle body (NOT a spacer), upgraded injectors and an open cone filter will make a huge difference. I noticed a big difference just with an open cone filter, something many on this site said wouldnt do much if anything. It OBVIOUSLY increased throttle response, gained power, quieted my motor and improved my gas mileage quite a bit. Lots of stuff to do that WILL make a difference. A tuner, chip, programmer, etc., wont.

Jamie57

How about removing the mechanical cooling fan and installing an electric one? Rotating that 10-15 lbs has got to add up to something. You used to be able to get un powered steering boxes too at one time. That pump is another drag on the engine. Don't use the A/C? Then get rid of it entirely without using an idler pull if you can. Drag racers now use an electric water pump instead of another pulley. About the only thing that cannot be removed from the engine is the alternator.
And don' forget on checking your tire pressure WEEKLY. It's incredible how much more drag is imposed on a vehicle when even 1 tire is 5 lbs down.

Gee oh Dee

That'll give marginal gains at best.

Jamie57

Yeah your right. It's an XJ . What was I thinking?

So don't bother doing anything. Just keep paying through the nose. After all It's an XJ and you knew it was a pig on gas when you bought it.
Any attempt to get better gas mileage will only result in ridicule from your peers.

Gee oh Dee

Wow, someone doesn't like it when someone else disagrees.

Unless your running around with the AC on all the time, swapping out the AC compressor will do NOTHING as its run off a clutch anyway.

And that's just one problem with your post.

Now, please feel free to spend all that time and money on a bypass pulley if you want. But I'm ok with using that money to do better, more useful things.

Again, marginal gain for too much work = not worth it.

Jamie57

You know for a MODERATOR you sure do like handing out the *****.
Do you ever have anything nice to say?

BTW even if the clutch NEVER engages it's still a drag on the engine.
You sure don't read well do you. I suggested to not use it (the bypass pulley).