Mark Houlahan
Brand Manager, Mustang Monthly
October 1, 2002

Performance upgrades on Mustangs don't always go as planned. That's a cold fact of life. Running changes in the production can mean the headers that fit your buddy's car may not fit yours, and so on. Sometimes a part will make advertised (or more) power on one car but not on another. This can be due to calibration differences in the Electronic Engine Control computer or even how the part works in conjunction with other performance parts already on the car. One thing's for sure-we wouldn't need a QA column if everything fit and worked to your expectations. But we're here to help.

While we don't condone the use of "off-road" exhaust parts or disabling the emissions systems, it's a fact that many people still do. With today's header technology and high-performance catalytic converters, it really isn't necessary to remove the emissions components, but it is an uphill battle teaching against what's been done since the early '70s to make power.

When off-road-style exhaust-system components are used on a '96-and-up OBD-II Mustang, the lack of a catalytic converter causes the EEC V to trigger the Malfunction Indicator Light-a.k.a. your "Check Engine" light-because the rear O2 sensors do not see a change in catalyst emissions. Driving around with the MIL illuminated is annoying, but it also prevents you from being warned about potentially more serious engine problems that would also trigger the MIL to come on. Short of taking the bulb out of the dash, there hasn't been a lot you could about it-until now.

Dallas Mustang Parts has come up with a product to help prevent illumination of the MIL due to off-road exhaust use or for overly sensitive O2 sensors (some Mustangs don't like high-flow, catalytic X-pipes and will turn on the MIL after installation). The Dallas Mustang Parts MIL Eliminator (PN 9074, $59.95) effectively "filters" the signal from the rearmost O2 sensors on OBD-II applications to prevent triggering the codes that turn on the MIL. These do not disable the MIL from functioning, so if a sensor-such as the mass air meter-fails, the MIL will still come on to warn you of the problem.

The installation of the MIL is fall-down simple and takes just a matter of minutes once you're under the car.

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