Jerrod Jones
Former Editor, Off Road
We used to be carburetor junkies. When fuel injection started showing up on our fullsize trucks, we were in a hissy-fit about a fuel delivery system that couldn't be readily modified. Then we finally pulled our heads out of the sand and realized that fuel injection was the off-road god's gift to wheelers. Electronic fuel injection increased our fuel economy, improved the throttle response and driveability of our trucks, made hard cold starts a thing of the past, and best of all let us drive our trucks to almost any angle without starving the engine of fuel. By the late 1990's, EFI was becoming easily modifiable, and complete aftermarket fuel-injection kits were showing up, so any gripes we previously had were now unfounded.
We only have one gripe left about fuel injection: Why aren't there a ton of 50-state smog-legal EFI retrofit kits available? It seems crazy not to have Air Resource Board exemption order (EO) numbers on all these retrofit kits. Fuel injection makes an engine more emissions-friendly than a carburetor because the EFI's control module is able to take engine temperature, vacuum, exhaust readings, and other variables into account and adjust the fuel delivery accordingly. But it is a long and costly process to get EO numbers from the government, even when fully deserving of them.
We did find one company that took the time and spent the money to get EO numbers for its retrofit kits: Howell Fuel Injection sells very affordable smog-legal fuel-injection kits for not only the Jeep inline-six, but now for the AMC 304, 360, and 401ci V-8 engines as well. We couldn't wait to get our hands on a kit. And at just $1,200, this kit won't be more expensive than the vehicle we're putting it on!
Once we got the Howell throttle-body EFI kit on, we headed back to Orange County Corvette to get another pull on the dyno. Our horsepower numbers were still lower than expected (this was not a generous dynamometer), but we bumped from 168.47 hp and 238.81 lb-ft to 181.30 hp and 258.89 lb-ft of torque. That's a 20 lb-ft increase of usable torque for the trail!
Not only that, but the driveability and general usefulness of this Cherokee Chief were improved immensely. Jeeps R Us tells us the fuel economy has gone up 4-5 mpg since the EFI swap-a huge increase! Also gone were cold starts, stuttering, and any dying out on steep inclines.
