In Part V of this buildup series we clued you in on our list of drivetrain component we'll be installing in our '68 J2000 pickup. To recap, we obtained a complete '92 4.0L engine, computer, and wiring harness out of a '92 XJ Cherokee from Scotty's Jeep, Truck, & 4x4 in Fontana, California. Also in that issue, we showed you the NV3550 five-speed transmission we got from Advance Adapters and the '84 Dodge NP208 transfer case that M.I.T. Drivetrain Specialists in El Cajon, California, rebuilt for us. However, while it's easy to select a modern fuel injected engine, it's quite another thing to get it wired and fired in the chassis.
First, we had planned on using Painless Performance's new Perfect Engine Management System for the 4.0L engine. We actually put the build on hold for several months while Painless finalized its programming of the Delphi MEFI 4 computer included in its kit. But, while the Perfect Engine Management system would greatly simplify the wiring and would no doubt offer seamless performance, the system was designed around the '97-'99 model year sensors. To make it work on our '92 engine would have required swapping over to the later '97-up distributor, TPS, MAP, and other related sensors as well as a GM-style coil. After totaling it up for our '92 engine the price for the extra accoutrements added nearly $500 on top of the $1,700 (as of press time) price of the engine management system. If this was a higher-end buildup we would have gladly forked over the cake, but as it is, the price for the engine management alone would rival the current value of the truck.
Our next plan was to go caveman and yank the injection and CPS-driven ignition. We put in a call to Holley for a 390cfm four-barrel carburetor, some spring loaded off-road needle and seats, and a 10-inch air cleaner. We then called Clifford Performance, which recommended a Mallory distributor, PN 4760101 for an AMC 258 engine to replace our crank-driven computer-controlled 4.0L unit, as well as Clifford's single-plane 4.0L four-barrel intake manifold, PN 47-4520. Unfortunately, the intake manifold was back-ordered and wouldn't be available by our deadline.
Finally, we received an e-mail from Tony Squier of Hotwire Auto who offered his company's services to pare down our factory XJ harness from an unintelligible mangle of spaghetti to a slick, easy-to-install harness with labeled connections and relays and fuses added as per our request. And it's not just 4.0L engines the company deals with. Hotwire Auto can handle anything from wiring a Dodge Viper V-10 to making a 6.1L Hemi seamlessly mate with a stock JK wiring harness. From modification of factory looms to stand-alone hot rod style harnesses for virtually any engine and transmission, Hotwire Auto can handle it. And the results are way beyond impressive. We received our harness from Hotwire Auto a week after we sent it to the company. You can see the results for yourself. Now we can finally start spinning wrenches on our drivetrain swap.
The Painless Performance Perfect...
The Painless Performance Perfect Engine Management System for the 4.0L engine would make for a clean, tidy package with its minimalist wiring harness and tiny Delphi MEFI 4 computer. However, the harness is built around the later '97-'99 type sensors and our older '92 engine would have required a considerable amount of retrofitting. It pained us to send it back (no pun intended) but it's a system better suited to a much nicer buildup than we are working on.
We then theorized that lots...
We then theorized that lots of guys rebuild 258 engines and add a 4.0L H.O. cylinder head, so why not just run a carburetor? To that end, we ordered up a Holley 390cfm four-barrel carburetor and Holley's spring loaded needle and seat assemblies for off-road use. The 10-inch Holley air cleaner would clear the valve cover, but the required Clifford 4.0L intake manifold was back ordered.
We were overjoyed when Tony...
We were overjoyed when Tony Squier of Hotwire Auto contacted us and offered his company's services to pare down this factory XJ wiring harness. With a full underhood fuse box, bulkhead connectors, and jumbles of wires everywhere, we would have been over our heads trying to hook up the right wires to get our engine running in our vintage truck.
Our factory harness terminated...
Our factory harness terminated in a nightmarish bulkhead connector. Just guessing and hooking up a wrong wire could have fried our fuse box, computer, engine sensors, or all of the above. The Hotwire-modified fuse block is a dirt-simple two-wire setup so even we can't screw it up.
In a nice touch, Hotwire Auto...
In a nice touch, Hotwire Auto added the necessary relays for the fuel pump, starter, and other required gizmos. The factory XJ ECU will operate all these components just as if they were in a stock Cherokee.
About a week after mailing...
About a week after mailing it off to Hotwire Auto, this is how our harness returned to us. Although we had Hotwire Auto modify our existing harness, the company can also supply its own stand-alone harness for use in just about any Jeep chassis and engine combination. Prices vary, but Hotwire charges about $700 for a modification like ours.
The company can set up the...
The company can set up the harness in a variety of configurations, but given the J2000's generous firewall real estate, we had the 60-pin terminal for the computer, the fuse block, and some accessory wires such as those for the 4x4 indicator lamp, backup lamps, and A/C compressor made long enough to reach the interior. We'll mount them under the dash on the passenger side where they'll be out of the way and protected from the weather.
It was no surprise when we...
It was no surprise when we discovered the factory 4.0L exhaust manifold was cracked. After tossing it in the dumpster, we ordered up a nice Edelbrock Shorty Header, PN 65923. Although the company offers its header in 409 stainless steel, the less expensive PN 65923 is constructed from 16-gauge mild steel with Edelbrock's proprietary Ti-Tech coating, which protects the header, yet absolutely won't burn off like paint or discolor like chrome.
Hotwire Auto not only pared...
Hotwire Auto not only pared down the harness to make it more manageable, but also replaced any corroded, crusty, or questionable wires it found. For our '92 harness, the company was able to reuse the factory connectors, but wound up replacing a lot of the wiring because of its poor condition. So now our harness is not only easier to install, but it's a lot safer to run.
The Edelbrock header comes...
The Edelbrock header comes with collector hardware, a header-to-downpipe gasket, and Edelbrock's own header gasket. The Edelbrock exhaust gasket is made from high-density, non-asbestos material that won't blow out like cheaper gaskets.
Installed on our 4.0L with...
Installed on our 4.0L with the intake manifold back in place, our Edelbrock 4.0L header should give plenty of clearance for the front axle and provide years of trouble free use.
Installed on our 4.0L with...
Installed on our 4.0L with the intake manifold back in place, our Edelbrock 4.0L header should give plenty of clearance for the front axle and provide years of trouble free use.