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specific stand-alone system since so many people are building wild motors and are unfortunately still relying on the outdated factory A9 computers, or buying expensive stand-alone systems," Richards said.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.

Harnessing The Power

While some might prefer to use their stock wiring harness and simply add a powerful ECU, Pro-M conducted extensive testing on a wide number of Fox-bodies and found that many of them had insufficient wiring harnesses with loose connections and bad grounds, after all, they are getting on in age. Seriously, why waste your time with a powerful new computer if it's going to operate through archaic wiring?

The replacement harness is a plug-and-play affair as it lies in the engine bay and inside the cabin just like the OEM unit does. Pro-M went so far as to offer year-specific harnesses as well, since Fox-body wiring harnesses had slight changes throughout the years.

We can attest to the quality of the harness with accurate wire lengths, hardy looming and all of the Ford connectors that push together with a satisfying click.

7. Jeremy Stanton of Stanton Performance helped with the removal of the tired, old Fox-body harness.
8. After two decades of service and 275,000 miles, most of which was as a highway patrol car, the factory harness was thoroughly cooked.
9. Since we’d previously maxed out our 42-pound injectors, it was time for bigger pumpers, and that necessitated the removal of our Trick Flow upper intake manifold.
10. Be sure to lubricate the O-rings on the injectors before installing them. We ordered the Siemens 62-pound injectors on a recommendation from the EFI wizards at Pro-M since they accurately operate at all duty cycles, even at low loads, which is hard to do with such a big unit.
11. Be careful when feeding the Pro-M harness through the firewall, since it can have sharp edges. With a little patience it will drop down in the stock location.
12. Speaking of patience, you’ll need some, and maybe a little rubber-lube to get the new weather-tight seal to squeeze in place. That’s OK—once it’s in, you’re assured it’s not going anywhere.
13. Inside the car you’ll find high-quality plugs, like this one for the Innovate wideband gauges.
14. Pro-M was ingenious enough to hide all of the relays in one spot for easy replacement. They even label them so there are no questions.
15. The Pro-M harness comes with this insulated blanket to wrap the relays. They’re protected when they’re mounted inside the kick panel where the OEM ECU once was.

The 92mm Monster

Since there was no way we were going to waste such a powerful computer and harness on an insufficient MAF, we stepped up to the Pro-M 92mm unit that is seriously wicked. The unit features cast aluminum construction with a bell-mouth inlet that removes the sampling element from the opening for maximum flow.

The air hog is capable of handling 1,500 hp and also features a unique 360-degree sampling area that averages the MAF signals for the most accurate readings. The unit has a connector that plugs into the Ford-style harness and even comes with a conical air filter.

Powerful Pipe

When Pro-M asked that we smooth the airflow into the MAF for the best signals (since turbulent air inside a MAF is highly undesirable), with on of their wicked 92mm MAFs, we also decided it was a good time to call Anderson Ford Motorsport for one of their infamous Power Pipes. These legendary cold-air intakes straighten out the incoming path of air into the blower by placing the MAF and filter inside the inner fender for a cooler, denser air charge. They're often imitated but never duplicated, since Anderson has been at it for years. Prior to the dyno we were already certain there were serious gains on the horizon, but we really had no idea (more on that later).

The Power Pipe smooths the incoming air and also relieves the restriction forward of the blower. Uncorking this section is generally good for a gain 1-3 psi of boost on blower applications without spinning the blower any faster. Seriously, it's more boost and more power simply by relieving restriction.

The unit came with all of the necessary hardware along with the high quality rubber couplers and detailed installation instructions. We'll admit that measuring and enlarging the fender-well hole wasn't easy. Take your time and measure several times before trimming.

Installation Process

Considering the undertaking of removing and replacing the entire fuel injection system on a Fox-body, the process was rather easy. We found it best to take our time and remain methodical throughout the process. Removing the factory harness was slow going since the arthritic clips were old and brittle. Nonetheless, after an hour or so the entire stock stuff was out and the new Pro-M harness was roughly laid out in the engine bay, giving us an idea of what we were after.

Pushing the harness through the firewall was tricky, as was mounting the new weather seal in its place, but some patience and a little rubber lube went a long way. After a solid half day, the harness was in the car and we were ready for blast-off.

While the install was rather painless, it did takes us a few attempts to get our laptop to communicate with the appropriate drivers for both the ECU and the wideband gauges. After a little IT work, we managed to sync up and free-air calibrate the MTX-L widebands and got the Pro-M ECU talking with the laptop.

16. Astute readers will note that Pro-M has gone to great lengths that no other aftermarket ECU company has in using a custom version of the genuine Spanish Oak ECU, similar to the ones in the S197 Three-Valve Mustangs, but with tons more brain power and Pro-M only features. The Visteon processor bringscapabilities to the Fox that were never previously possible.
17. When we say Pro-M is detailed, we mean it. Even down to the wires, which are individually marked so there’s no problems during the install. This is the passenger-side wideband gauge wire.
18. We opted to use the Innovate MTX-L wideband gauges with the Pro-M ECU since having the computer run off the widebands brings a whole new level of tunability.
19. Since the new ECU monitors each bank of cylinders, you’ll need to run a pair of widebands, and since it’s side specific, a little tape on one side helps from getting them mixed-up.
20. Don’t forget antiseize on the new O2 sensors or you’ll be sorry later.

The Software

Even though the pre-installed tune from Pro-M was surprisingly accurate, we dove in feet first with the software. We found it easy to use once we stared at it for a minute and quickly navigated the working pages, real time data logging and monitoring tools. A call or two to the helpful tech line at Pro-M got us answers to additional questions, and before long, we were adjusting the 3D graphs of our load and lambda fuel tables against our spark trim.

The real-time data-logging might not offer a screen play back mode like other stand alones, but we found is easy to view our logs in the included graph form. Another note about the capabilities of the ECU: Tuner extraordinaire and all-around Mustang badass Drew Wallace of AED in Shingle Springs, California, noted that when zooming in on the logs, the graphs remained startlingly clear. He attributed this to the fast sampling rate of the ECU and was beyond impressed.

The real-time data logging was helpful during our dyno pulls when we encountered a lean condition that was ultimately traced backed to the maxed-out stock fuel rails and lines. While monitoring the injector duty cycle, we noticed our massive Siemens 62-pound injectors were pegged out. Simple math revealed that while the injectors were sufficient, they were starved by the stock lines and rails. Logging in real time kicks ass!

We also found the pot-box to be helpful during tuning sessions since it allows for tweaks to the tune with a simple poke of the up and down arrows. Instead of rotating between the computer and your widebands, you can simply tap the arrows to fatten or lean out the mixture as you watch the wideband gauges in real time—no hunting for certain boxes and manually adding in a number.

The dual internal memory of the ECU was also nice. As we explored different parameters of the tune we could save our changes on a temporary memory portion. If it was something we liked, we could write it to the permanent memory; if it wasn't a keeper, we reverted back to the previous map without having to constantly write to the ECU.

21. Note the quality Ford connectors on the new harness—this sucker fits like factory!
22. Although the Pro-M has a sophisticated internal ignition coil control with four individual processors that actually averages the firing events to makeup for the shaft play in the distributor, it still connects to the factory TFI module. Note the new ignition spout connector that is easily disconnected.
23. All of the connectors on the new harness are better than factory units and every wire is cut and loomed to precise lengths.

On The Dyno

With the Pro-M base map loaded, we put the Smog-Legal Killer in Drew Wallace's hands on the AED Dynocom dyno and it proceeded to make our jaws drop. We knew the new ECU and Power Pipe combo was going to unlock some ponies, but we had no idea how many.

The first pull of the day unearthed a 610 hp and 595 lb-ft at the wheels on 91-octane pump gas. You read that right—over 600 hp to the tires through cats, the smog pump, and all! Our previous best was 523 hp and 530 lb-ft at a peak of 12 psi of boost. The new combo upped boost to 15 psi at redline for gains of 87 hp and 72 lb-ft. The Power Pipe seriously uncorked the blower and allowed the wicked AFR 195 heads and Comp Cams blower cam to shine.

While the hero dyno pull was great for morale, the car was leaning out up top. As mentioned, we used the new ECU to track the problem to the stock fuel rails and lines. When pulling 10 degrees of timing didn't kill enough power, we decided (sadly) that the best method to keep the stock block alive was to add a larger blower pulley in hopes of dialing it back to 10 or 12 psi at redline.

Who would have thought we'd be trying to remove power from a combo that was already compromised by cats and other smog-related concessions? If only we had an aftermarket block, we could get 650 hp at the wheels through cats and all.

Read ’em and weep, that’s 610 hp and 595 lb-ft at the wheels on 91 octane pump gas through cats, spinning a smog pump and all. The Power Pipe upped boost from 12 psi to 15 psi at redline with the stock pulley, proving how good the AFR 195 heads and Comp cam breath. The Pro-M computer and Anderson Power Pipe boosted power by 87 hp and 72 lb-ft at the wheels over our last pull.

Smog-Legal (Sort Of)

Up until this point, we were legitimately smog-legal. Sure the car had larger injectors, but that didn't stop it from passing the visual or tailpipe emissions. But in search of more power, we've officially entered some gray area.

Sure the Power Pipe doesn't have a CARB EO number, and admittedly the Pro-M computer ditches the EVAP provisions, but we wanted to see if the car would still pass the tailpipe emissions. A trip to a smog station revealed that while we no longer passed the visual portions, the car still passed tailpipe emissions by a decent margin. The new processor actually allowed us to clean things up down low, which helped the numbers. Hey, we can tune for emissions and power now.

As for the visual portions, well, anyone with a little imagination can figure out a simple solution, but you didn't hear that from us.

24. Although the Pro-M computer ditches the provisions for the EVAP smog equipment, there’s no stopping someone from making it appear like it’s actually running…
25. Here AED helps hog out the inner fender so the gargantuan Power Pipe can snake into the inner fender for gobs of cool air and a straight path to the MAF. It takes a steady hand to not hack the hole.
26. Here’s a look at the Power Pipe and the Pro-M 92mm MAF hiding inside the inner fender. You’ll have to remove the inner liner to get everything in there.
27. Make sure all of the connector pins are making solid contact between the MAF adaptor. We had intermittent running problems that we traced back to the plug not being properly seated despite hearing the click. We can thank Greg Wallace from AED for finding the elusive problem. Simply removing the connector and making sure it was properly seated solved the issues.

Wave Of The Future

Sure, the Pro-M ECU isn't cheap, but at a few ticks under two Gs it's a steal considering its capabilities, plug-and-play harness and the overall quality of the system. We can't tell you how awesome it's been to have a sophisticated system that actually uses wideband O2 sensors to help dial in the perfect tune. We never thought we'd see the day that Fox-body tuning would become so easy, but thanks to companies like Pro-M, owning a Fox is that much better. Welcome to a new era of tuning.

Have a look at the 3D load and lambda fuel tables of the Pro-M software. It’s amazing how powerful the new ECU is and it brings a whole to era to the Fox-body. The software is also easy to use for the average Gearhead–no geek degree needed!