Justin Fivella
November 12, 2013

Well over a decade ago, Fox-body fans rejoiced with the advent of the first replacement performance chips and piggy-back computers. Gone were the days of limited tuning with little more than a timing light and an adjustable fuel-pressure regulator. We'd truly entered a new tuning era for the Fox, or so we thought. But time and technology marches on and trickle-down technology from newer cars has finally reached the Fox-body as we again find ourselves in a new era of Fox performance: The plug-and-play, stand-alone computer days are upon us.

By the time MM&FF project Smog-Legal Killer was ready for its third chip—due to the ever-changing motor combination, we realized there had to be another solution beyond visiting the tuner for a new chip every time we made a change. But we didn't want just any solution; it had to be a complete plug-and-play system with supreme adjustability, an easy program interface with cutting-edge features from the newer cars. Thankfully, Chris Richards of Pro-M Racing had so many requests for a high-quality and easy-to-use Fox-body stand-alone computer system that he went ahead and created one from the ground up.

"We saw a need for a quality and affordable Fox-body specific stand-alone system since so many people are building wild motors and are unfortunately still relying on the outdated factory A9 computers, or buying expensive stand-alone systems," Richards said.

Different By Design

Although Pro-M wasn't the first to create a plug-and-play stand-alone for the Fox chassis, its system offers some exclusive features that make it hard to beat. For starters, the computer itself is none other than a hott rodded version of the famous Spanish Oak ECU, like the factory Visteon units in the Three-Valve S197 cars, but with tons more processing power and Pro-M only features. This not only means incredible brain power and processing speed far beyond the factory Fox stuff, but it's also stone reliable. How well an ECU withstands things like heat and vibration, both common in a hopped-up Mustang is crucial.

The Pro-M ECU is also self-diagnosing, as it continuously checks itself for faults. Forget guessing if the ECU is the culprit because this computer will throw a Check Engine light if it is.

Unlike fuel-only aftermarket ECUs, the Pro-M unit allows for full control of the air/fuel ratio and timing in an easy-to-use format known as "load and lambda." In tuner lingo, load is the mass of the air being ingested by the engine divided by the maximum potential of the engine. In other words, the mass of the air being ingested at any given time is the value being provided by the MAF, and an engine's potential is the amount of air that would be in the combustion chambers if all of the cylinders were full. In this case, a load of 1 would be a motor running at maximum potential and a motor running at 10-percent would have a load value of 0.10. According to Richards, most naturally aspirated motors won't see over 0.85 on the load scale, as anything greater is reserved for forced induction.

The other piece of the Pro-M pie is Lambda, which unlike the more common form of measurement, AFR, Lambda is more consistent. According to Richards, the Stoichiometric (ideal) AFR measurement for gas varies depending on the fuel: Normal pump gas is 14.7:1, E10 is 14.2:1 and E85 can vary from 10:1 to 12:1. However, Lambda will always be 1, no matter the fuel. Users simply select the type of fuel they're running and the ECU will adjust accordingly.

Since the Pro-M ECU comes with a preloaded map that is nearly perfect for most applications (seriously, we're not joking here), even tuning for forced induction is easy since lambda loads over 0.85 start bringing the mixture back into the mid 11s. For those looking to adjust timing with boost, the system allows users to pull timing with an optional three-bar MAP sensor or simply by adjusting the spark advance values in the spark table for the given load values.

Here’s your E-ticket ride to modern technology in a Fox-body—the new Pro-M Racing stand-alone, plug-and-play computer system.

Other noteworthy features include a two-stage rev limiter, decel features that cut fuel when decelerating for better fuel mileage, built-in fan control wiring, and an interface that uses the stock coolant temp sensor to activate electric fans—yeah, it's got everything.

If that's not enough, the unit will soon have nitrous capabilities to feed in nitrous as you dial out spark. The system also has individual cylinder tuning, which means if your back cylinders are lean, you can simply fatten them up for added safety.

The ignition control of this powerful ECU is another standout feature since the Pro-M ECU uses an integrated ignition module that's already inside the ECU. In fact, four individual drivers run the ignition coil for the utmost accuracy. According to Richards, the timing control is another area where the Pro-M excels.

"Since distributor-type ignition systems are typically victims to distributor gear lash that can cause inconsistent signals, our ECU averages the signals produced by the distributor just like most coil-on-plug systems," he explained.

As if that still wasn't enough, the ECU is also able to run two MAFs for those wanting to run twin turbos or blowers, and it also comes with programmable outputs should you want to run a shift light or a failsafe. For those who'd prefer to run Speed Density or Speed Throttle (Alpha N) instead of MAF-based tuning, the Pro-M will easily accommodate those as well.

The fact that the system can be configured to run off the factory narrow-band oxygen sensors (O2) or aftermarket widebands makes it all the more useful. We opted to use the recommended Innovate MTX-L wideband O2s since they give users far more control than the limited factory units.

1. The Smog-Legal Killer has repeatedly made more power than expected, so this time we stepped up to these bad boys, Siemens 62-pound injectors. These will have plenty in reserve for future mods.
2. Nothing compares to an Anderson Motorsport Power Pipe. This famous CAI is known to unlock serious power and up the boost on blower cars simply by relieving restriction.
3. The Pro-M 92mm MAF is one of the big dogs on the market and comes with top-notch features like a venturi inlet and an element that has a 360-degree sampling spread. Try finding that in other MAFs–not!
4. The Pro-M computer can run off the stock narrow-band O2s or optional Innovate MTX-L widebands. Of course, we opted for the latter to take advantage of the insane processing power of the new ECU. Welcome to the new age!
5. Yes, those are new OEM Ford connectors on the Pro-M harness for a factory like-fitment that also plugs and snaps right into place. Pro-M has taken the time to do it right and the proof is in the pudding… err, wiring.
6. Out with the old ECU and in with the new. The A9L was an impressive computer for its day, but technology doesn’t stop, and having the power of a modern computer in the venerable Fox chassis is the best of both worlds.