Jet Performance ECU Module Installed on 2005 Jeep Wrangler Unlimited

I had already replaced the intake, throttle body, and exhaust on the TJ with performance, aftermarket products and wanted to see if there were any other easy modifications I could make that would squeeze a little extra horsepower from the 4.0 liter (250 cubic inch) power plant.

I have no intention of doing anything complicated because I use the TJ as my daily driver and can’t have it out of commission for extended periods of time. I had never tried a chip on any of my previous vehicles and was curious about how they performed.

The ECU (Engine Control Unit) in your vehicle is the computer "brain" that controls many of the important aspects of your timing, emissions, spark, air/fuel ratio and many others. Some ingenious companies have made improvements to the stock ECU settings that came with your vehicle from the factory and have made performance improvements to them. Some companies sell entirely new ECU products that replace the entire "Brain" and some have created "piggy-back" modules and programmers that mount to the existing ECU to improve performance.

I did some research and decided that I would try the Jet Performance Module and since it was a piggy-back version it would be an easy, no-nonsense installation. I made a call to the crew at www.motorweb.com to get one sent out.

It took me longer to write this article than it did to install the Jet Performance Module on the TJ. It was simply a matter of disconnecting the negative battery cable, unplugging the stock wiring harness and plugging it in. Once connected, I reconnected the battery and it was off to the races.

I noticed that the TJ had better low end torque and it was much easier to squeal the tires than before the install. I also noticed I seem to be running at lower RPMs on the highway which I’m hoping will translate into better fuel economy. The Dyno charts on Jet’s web site say that their (part number 90015) "stage one" chip gives the TJ another 10-12 horsepower, but I’m thinking I may have a little more since I got the "stage two" chip. Jet’s web site says the Stage 2 module features more aggressive programming to make the most horsepower and torque available. It also says that fuel and timing curves are extensively modified for peak performance and drivability.

Overall it was an easy installation and I got some extra "pep" out of my little 4.0, straight six engine. I can’t wait to see what it will do on the trail.