(Editor's Note: To enhance performance all images have been rendered into thumbnails. These small framed images may be clicked upon to show a larger version of the image.)

"Fuel-injection". A word when mentioned around many Jeep CJ owners out there grabs their attention. You see this particular breed of CJ owners often, usually as they curse the Carter BBD carburator that seems to have a mind of its own, and then raise their hands skyward to sadly beg for a solution. Well, Holley has provided one possible solution which this CJ owner has recently tried.

Holley's solution is their "Pro-Jection" Throttle Body Fuel Injection (TBI) kit for the 258, (part number 501-2). This kit is intended for use on the 1979-82 Jeeps with 2 bbl carburetors and manual transmissions. Please note that this particular kit is not intended for use with the 1983-1986 Jeeps, since the original factory computer on these applications controls their ignition systems and the two computers would get their wires crossed fighting for control (figuratively speaking).

Bringing your Jeep into the world of modern fuel injection has many benefits: These include easier starting, improved idling, and in most cases increased fuel economy.
Another common problem that off-road jeeps face that this kit helps to solve is stalling due to fuel sloshing and starvation caused by the extreme angles the jeep may experience on the trail.
The Holley TBI unit is completely adjustable, even from the driver's seat and on the fly, making fine tuning your performance for altitude changes or other variables a cinch.

Installation 

View of TBI and adapter in engine compartment. Note the adapter provided to use the stock air cleaner. In this case a K&N filter was used instead

1. Disconnect the negative battery. Very important when dealing with open fuel lines and electrics. Also remember to keep sparks and flames away.
   (Safety Notes: If working in a garage provide adequate ventilation and beware of gas heaters, furnaces, water heaters or gas dryers that may have an open pilot light flames. Also when in the presense of gasoline vapor be aware of electric motors, grinders, drills, welders or any other tools that may cause electric arcs or sparks. Oh yea - it may be a good idea not to smoke while doing this.)
2. Start by removing the carb and it's vacuum lines. The included diagram with the kit will assist you in hooking up your old lines to the new TBI. I discarded many of the non-required vacuum lines as emissions tests are not required and they were just in the way. Also, I used a custom chrome K&N setup, so I had to get rid of the vacuum line that went to the air cleaner. 

Closer view of TBI & Adapter

3. Next remove the fuel filter and check for the presence of a return line. On my Jeep, the return line came off of the fuel filter. If your Jeep does not have a return line, you will need to obtain some 5/16" fuel line and fabricate one.
4. Remove your fuel pump and replace it with the supplied block off plate. Make sure to completely scrape off the old gasket as a new one is provided.
5. Prep the intake by removing any old spacers and gaskets from the old carburetor.
6. Using the supplied new gasket, attach the adaptor plate to the intake with supplied countersunk bolts.
7. Attach the throttle cable bracket to the side of the adaptor plate.
8. Install the three studs for the TBI and place the TBI and throttle kicker

TBI & Adapter showing fast idle solenoid (center).  Also not the relocated throttle cable on the passenger side of the TBI unit.  This would require some custom fabrication to use with the kick-down linkage for an automatic transmission.

solenoid bracket over the studs (the bracket goes over the front one) and tighten everything down.
9. The last thing to install on the engine is the coolant temperature sensor. On mine I used a passage meant for a thermal vacuum switch or CTS (This is found on 1983 and newer 258 engines; I had it because my new engine came from an 1983 model year Jeep) on the intake. If you don't have anything like this available, you can use a brass T and put it in a heater hose. The only requirement to be sure to remember is that you must put a ground wire from the T fitting to the block, as the rubber hose is of course ungrounded and this will cause the CTS not to work properly.
10. The next step is to install the ECU box. Since the ECU is meant to be adjustable by the driver, it should of course be mounted near the driver. I put mine on the floor next to the driver's seat on the side by the door. I can reach it to make adjustments and it was near a drain plug hole. I used this hole (which I had to file slightly) to pass the wiring harness through. After you get all the wires hooked up and running, make sure to seal the hole with silicone to help prevent water leakage. (editor's note: for jeeps that do serious water crossings and occasionally get water in the passenger compartment a higher location may be better, a swamped ECU can shorten your four wheeling day in a hurry)
11. Following the instructions hook up all the wires. This just involves trimming them to the proper length, then putting on the supplied connectors and plugging each wire into the harness. Make sure you tie-wrap everything out of the way. As you note in the pictures, we tied all of my stuff up to give a factory like look. This took a little longer, but the results were worth it.

 

Prefilter for fuel pump mounted on frame rail.  Prefilters are always a good idea to protect electric fuel pumps.	Fuel pump mounted on frame rail.  If you desire to carry a spare pump it could be mounted right above for a fast switch over.

Mount the fuel pump and filters. There are two filters, a pre-filter before the pump and the main filter after the pump. I mounted it on the passenger frame rail where it comes over the axle (see picture). Be warned, AVOID having a full tank of gas when you do this. Jacking up the truck made it easier, but also doused us in gas (I just filled it up before the engine swap/EFI install). Make sure to use a tubing cutter to cut the fuel line, as other methods can cause sparks or get shavings in the fuel line.

 

12. The instructions said to mount the filter right after the pump, but in thename of easier repair I deviated from the instructions here. Mine is on the passenger side of the engine compartment making it easier to reach when it comes time to change it. Note the fuel line going over the valve cover to take it over to the TBI unit.

    Main fuel filter, mounted in the engine compartment for easier access & maintenance.

    If your Jeep doesn't already have a return line, you will fabricate it here. Since mine already had it, it was just a matter of using 5/16" hose to hook it up to the TBI.
13. All that's left is to install the adaptor and air cleaner. I used a stud extension and installed a K&N chrome open air cleaner. The part number for it is 60-1030. Be warned that on mine, clearance was a problem. I flattened out the wing nut to clear the hood, as I now have a ding in the hood to prove that it didn't clear at first.

• It has improved power, far more than a friend's similarly set up 258 (both have a fresh engine, Clifford single outlet header, turbo muffler & free flowing exhaust). The big differences are that mine does have a little more lump to the cam and he is still running the stock BBD carb.
• Starting is much easier, and idles smoother. This is especially noticeable when it's cold out.
• Its off-road performance is much better now too, with absolutely no problems to date. I expect that the problems with stalling when off-camber or at a high angle are a thing of the past as well
• The fuel economy is slightly better, but I am running a little more agressive cam than I did previously and I think everything may still be running just a little on the rich side. However the performance I am experiencing now is so good, I really don't want to change any of the adjustments.

Well, I hope this article has provided some insight into this particular aftermarket EFI install. If you have any questions, feel free to E-mail me and I will be glad to answer them.