Jethro4days

Hey everyone, maybe some of you can shed some light on this subject. I own a 00 xj limited. As everyone knows the 00 and 01 are the problem years for the xj. I was just curious. Aside from the 0331 head and the lp front axle. What's other parts on my xj are sub par compared to other years?
Thanks everyone. BTW here's a picture of the rig.

SeriousOffroad

That's about, unless you are blessed with Dana 35.

TwistedWrench

Yup, other than that you've got the same weak points we all have, lol.

But you have cup holders!

extrashaky

Yours looks just like mine did when it was younger, before several mishaps.

It's not really sub-par, but the '00 and '01 has electronic ignition with a coil rail instead of a distributor and plug wires. The rail has three coils mounted on it, and the rail itself mounts directly on the plugs. It's a waste-spark system, where each of the coils fires two cylinders at the same time, both on the power stroke and the exhaust stroke. What that does is burn away any fuel remaining in the cylinder after the power stroke for emissions purposes.

A lot of people hate that coil rail, but it's not actually a bad system. The electronic ignition gives you about the hottest spark you'll get. You have fewer parts to go wrong. And the computer can keep the thing running long after the distributor models would have given up. I didn't like it until I started doing research on trying to upgrade it and realized there are no upgrades, because the stock system is really quite good.

The only other actual sub-par element depends on whether you have California or EPA emissions. In 2000, the truck came with one or the other. In 2001, only the CA emissions package was available.

The big difference is the number of catalytic converters and the number of O2 sensors. The EPA (also called the "49-state") version has one catalytic converter under the middle of the vehicle and two O2 sensors. The CA version has two additional small catalytic converters (usually called "precats") located directly under the exhaust manifold, as well as 4 O2 sensors. Chrysler marketed the CA version as "50-state emissions" in an attempt to trick people outside of California into buying something they didn't want to improve their emissions stats.

The drawbacks:

There are more O2 sensors to go bad, and cost to replace them is therefore higher.

There are two more cats to go bad, and they can be rather expensive to replace.

There are fewer options for bolt-in headers, even with the EPA version. The EPA version uses a twin downpipe in place of the precats, so your header options are the same with either version. It is possible to modify the EPA version to accept an earlier exhaust configuration, but by the time you do that you might as well have just bought a set of Torque Tubes. You can't easily modify the CA version because of the precats, and since the computers and wiring harnesses are also different for these two versions, so you can't just swap one for the other.

Additionally, because the twin downpipe or precat configuration takes advantage of the extra drive shaft clearance of the low pinion front axle, swapping in a high pinion D30 can cause the drive shaft to bang into the downpipe if you don't install a lift first.

To figure out which one you have, just look down under the manifolds. Do you see two big lumps in the pipes with O2 sensors above and below them? If so, you have CA emissions. You can also look at the emissions sticker in the engine bay directly in front of the driver. It will tell you whether the truck came with CA or EPA emissions.

CCKen

The Camshaft Position Sensor has a habit of biting you on the **** when you least expect it.


Here's the exhaust that was referenced:

HappyTrails

My 79 Spitfire had one of those mounted that close up under the intake. Back in that day there was no FI and no computer or O2 sensor. It just flamed off any unburned fuel. And if the engine was running rich, well, it glowed cherry red! Well known source of engine fires. We called those things "catastrophic perverters" instead of catalytic converters. Hopefully the Jeep set up is not so terrifying!

Jethro4days

I do believe I have the California version unfortunately.