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1978 Jeep J10 Fuel Injection Install

50-state-legal, bolt-on fuel injection

Verne SimonsPhotographer, Writer

Long about 1991, pretty much all Jeeps came directly from the factory with fuel injection installed on their engines. This change was for good reason. The later years of carbureted Jeeps are a horrible mixture of old-school fuel delivery technology plugged up with some rudimentary computer controls that in theory should have made these Jeeps run cleaner and better. Its not, and they don’t run nearly as well as Jeeps with fuel injection. These computer-controlled carburetors are known for their lack of reliability and generally have a negative reputation now that 20 to 25 years or so have passed. Other earlier carburetors are simpler, and while most are more than adequate for on-road use, not all do well in the hills. Some work pretty well off-road if they are tuned properly from the get-go, but this is the exception rather than the rule. The fact is you’ve probably heard someone recommend fuel injection as a cure for any and all carbureted Jeeps. In order to get a Jeep with a carburetor to run well off-road takes more than just having the physical parts. You need to know how to tune that carb for off-road use, or have access to someone who knows how to tune it. Fuel injection allows for a much more plug-and-play situation where the fuel and air mixture going into your engine is controlled by a computer that knows what it is doing (computer-controlled carburetors are much less forgiving). A good fuel-injection system can compensate for altitude as well as other driving conditions. Also, fuel injection generally works much better off-road than some properly tuned carburetors and is much more robust with regard to changes in weather, altitude, and wear-and-tear.

So what does one do to get fuel injection on a Jeep if all it currently has is a lowly carburetor? Well, one of the most common routes is to adapt a relatively simple, mass-produced, factory-available fuel-injection system in place of an old cranky carburetor. The name Howell Engine Developments is practically synonymous with Jeeps and reliable fuel injection conversions. For years this company has offered several different fuel-injection systems for Jeeps. Some of these systems use a GM-based throttle-body injection system. It just so happens that the GM TBI system for a GM 4.3L V-6 can be adapted to fuel an AMC 258 I-6 or Buick even-fire V-6. Also the GM TBI for 305ci V-8s and 350ci V-8s can easily be adapted to an AMC 304ci V-8, AMC 360ci V-8, or AMC 401ci V-8. To this end, Feature Editor Simons has been running a Howell TBI system on his Buick V-6-powered ’49 Willys for about five years without issue after fighting another aftermarket injection system for years. This meant when the carburetor on Simons’ ’78 J-10 died a slow death, it was an easy choice to move to Howell’s 50-state-legal TBI kit for AMC V-8s. Follow along as we install the system and enjoy its reliability and consistency.