As many longtime Jp readers may remember, our little '99 XJ project vehicle used to run a 4.6L stroker with all the goodies. It lived above the front axle for 20,000-25,000 miles. Then one day several years ago for no apparent reason the engine lost all compression in the number-six cylinder. This author didn't have time in his crazy-hectic schedule to do a post-mortem and, since the Cherokee served as a primary commuter and daily-driver it needed to get fixed fast. We dropped the Jeep off at Jeeps-R-Us in Laguna Niguel, California, where owner Larie Tales and his topflight crew of mechanics swapped out our popped stroker and installed the factory 4.0L in no time flat. But by then our big bosses kinda dropped the ball on the registration and the Jeep languished in our company parking lot. It was pilfered of parts and collected dust for the next several years.
So in addition to upgrading the suspension and front axle (which you read about in first three parts of this story), we needed to give the Jeep a good going-over to determine which parts were pilfered, which were not functioning, and which needed maintenance. For starters, the Check Engine light wouldn't turn off, so we took the Jeep to All Wrangler Off Road in Wildomar, California, where our buddy Jay Miller diagnosed a computer-sourced injector misfire from the custom 4.6L tune in our Unichip piggyback programmer. We removed the Unichip and the Check Engine light went away and the vehicle ran more smoothly.
Then we flushed and changed every fluid, filling the 120,000-mile stock 4.0L with a fresh Car Quest filter and 10W-40 Valvoline, loaded the AW4 with a new filter and some high-quality Dexron III fluid, and changed out the ATF in the T-case for good measure. We remembered that when the rear axle was snaked out of the Jeep the custom Lokar E-brake cables were removed. The hardware and cable housings were still there, but once the inner cables are removed from the adjuster block the ends kinda unravel and it's impossible to reinstall them. We ordered new inner cables, cut them to length, and installed them rather than messing with the old ones. Then it was a simple matter of checking the condition of the Performance Distributors Firepower ignition system we installed years ago (it was still perfect) and adding a nice BBK 62mm throttle body and a replacement K&N Fuel Injection Performance Kit (FIPK); our original FIPK had a big hole drilled in it for our nitrous system, which we're not using anymore. So now that it's again safe for public roadways, check back next time when we'll equip our Project JR with some outback expeditionary and recovery gear for extended trips through the wilderness.