Cherokee 4.0

you gotta do it all within 5 secs and you will have to get to get at lesast one code, which is the 5-5 code for end of message

8lugnuts

Like UDog said, you must do it fast. You know how you turn the key into the On position just before pushing all the way to start, and you see all the lights light up on the dash? Well, from the off poistion turn it to that position 3 times and leave it in the on position at the third time.

Do this quickly, then while the key is in the on position, all the dash lights will go out as usual, then wait. Eventually you should see the CE light start blinking like a turn signal, then it will pause. Count the number of times if flashes. It will do it again, then pause, count the number of times is flashes again: this is your first code. i.e. 5-4 or 54. It should continue this until the final code is reached, which is 5-5.

I used to do this all the time with my Shelby CSX and my Omni GLH, learned a lot by learning what the codes are.

As an alternative, what major auto part stores are near you? AutoZone, CarQues, Napa, and Advance are near me and I know for certain Advance will use their scanner to scan your 'puter on-the-spot, no charge.

As another alternative, I think you can reset the 'puter by disconnecting the battery and the 'puter's cables for a minute or so(can someone verify this?). If the problem recurs then you have a bonfide problem.

hope this helps,
8lugnuts

97XJMopar

Always run 93, that tank was mostly highway, around town driving as long as I dnt keep my foot out of it I'll get a avg of 22

asatxj

If his is post 96 the key thing doesn't work need to go to AZ and have them pull codes.
Yes bad cat will get you a CEL. Go to performancepeddler.com and get a perf cat from them. I got a cat, flopro muffler and a handful of clamps for less than $100. Great people too. Oxygengeek.com has good prices on our sensors.
Been there done that.
BTW you can get Good $$ for your old cat. might pay for the new muffler. check craigslist, you'll find someone buying them.

jeepxj00

You run 93 octane in a Jeep? Doesn't that seem like a waste of money?

Cherokee 4.0

x2

ShredSled

I'd agree to a point... unless you're running significantly higher compression ratio, have a forced induction set-up, or altered your timing... otherwise I don't think you'll see much benefit, if at all just from running higher octane gas.



I can't recall right off the top of my head at the moment, but I don't remember my '96 XJ as having an O2 sensor after the cat? In which case, how would it throw a code?
I'll have to run out to the barn and take another look later tonight.
Now I'm kind of wondering if my cat could be taking a dump too.... Can't have much life left in her!
Was just looking on ebay, they have some Magnaflow high flow cats for about $70 shipped... not too bad I guess.

97XJMopar

If i run regular 87 valvetrain makes more noise and u can tell a big diff in performance, maybe it's just where I've ran it so long its addicted to it like crack

ShredSled

I'm just curious, why would it effect valvetrain noise?

Are you talking about "pinging" or detonation? That would be really the only sign you need to up the octane rating.
Unless something was done to the tuning, I still don't believe it can give you any hidden performance gains.

broncofire75

If my Jeep was an offroad only rig would yall recommend just gutting or deleting the cat all together? Just curious. Lol

Cherokee 4.0

Yeah i love it after i did it...i have about ten people i know very closely...all with cherokees that have done it and it runs great