Holley Sniper EFI Meets Old Jeep

Fuel Injection in a Box

Jay KopycinskiPhotographer, Writer

They say once you taste steak, it’s hard to go back to just eating hamburger. Such is the case with electronic fuel injection versus basic carburetion. So, what if you have an older carbureted Jeep that doesn’t quite warrant an engine swap, but you want more of what a modern fuel system can provide. You know: easy cold starts, smoother idle, increased power, and better fuel economy. Well, Holley may have your answer.

The 1969 Jeepster we used for this exercise in modern fuel delivery was powered by the venerable, but still carbureted, Buick 261ci V-6, a common enough engine in Jeeps of the day. It had occasional problems with cold starts, plus it stumbled badly when climbing hills. The latter killed a lot of the fun factor when out wheeling. The owner chose to upgrade the fuel system with a Holley Sniper EFI Self-Tuning Kit. The throttle-body system flows up to 800cfm and supports naturally aspirated engines making up to 650 hp. It has an integrated fuel pressure regulator, along with the ability to function with a wide variety of OEM and aftermarket ignition systems.

The engine control unit (ECU) inside the throttle body assembly will tune itself with a self-learning technique. The user can also override many of the parameters using the 3.5-inch display controller that comes in the kit. The ECU is highly customizable and includes rev limiting, nitrous injection control, and many fuel mapping functions.

A complete wiring harness is included, and the only external connections needed are battery positive, switched ignition, tach signal, and ground. It has the ability to control electric fans, interface with an air conditioning relay, and drive an aftermarket tachometer or Holley EFI analog gauges. A wideband oxygen sensor is used to monitor exhaust composition and provide data to the ECU to further tune the fuel map for the particular engine.

With the hardware and wiring install complete, we turned on the ignition and followed the setup instructions in the Calibration Wizard software using the handheld controller. It walked us through a series of questions about the engine it was attached to. Once it set up a baseline fuel map, we were instructed to fire up the engine. It started almost immediately and soon settled into a nice base idle speed.

After a short adjustment of the idle settings it was time for a test drive. There was initially a bog off idle when stepping on the gas. However, the ECU quickly starting learning once the engine hit normal operating temperature and smoothed everything out. Driving the V-6 powered Jeepster quickly revealed a smoother running engine with more power under throttle than it ever had with its previous 4-barrel carburetor.