Tom Wilson
July 1, 2003

Horse Sense:
Knuckle-dragging 5.0s are sure to benefit from AEM's powerful new engine manager immediately, and soon, so will 4.6s. By the time this makes print, the EEC V version of the AEM computer should be only a month or two away from availability.

We Ford enthusiasts have been alternately blessed and plagued by Ford's Electronic Engine Control IV engine-management system. Powerful-and in its mass air version, highly adaptable-EEC IV has been all the engine management most owners could want.

On the other hand, EEC IV is likely the most mule-headed and secretive management system ever in widespread use. Its complex inner workings are for all practical applications a secret of Ford's, and when the blowers and turbos go underhood, adapting EEC IV to seamlessly meet the engine's new demands becomes impossible. So, while electronic aids have evolved from intercept-and-patch strategies to rather complex add-on boxes, complete control has been offered via replacement engine-management systems. These so-called stand-alone systems do not work with EEC IV-they replace it.

The advantage of replacing EEC IV is not that the stand-alone systems are better-nearly all are far inferior in complexity and often in sampling rate and response speed-but rather that they are designed to be tuned and are thus responsive to input. To date, such systems have been race-oriented, so the complexities of EGR function or air conditioning have simply been discarded. This has made such systems poor choices for streetable cars.

When the computer does all the work, there doesn't have to be much stuff in the sales box. Thus the AEM Plug & Play Programmable Engine Management System easily fits into a small carton. As expected, the support information is on a CD ROM, so there's a bare minimum of paperwork to get the system up and running.

Furthermore, stand-alone systems have been built around their maker's vision of sensors and wiring. To fit these stand-alone systems to a Mustang originally carrying EEC IV management, nearly every vestige of EEC IV must be removed and replaced with the new system. Thus the Ford computer, wiring harness, and sensors had to be ash-canned in favor of new bits. This is a lot of work, expensive, and plain-old inefficient, as much of the hardware being tossed is of high quality.

But not anymore. We just took a quick look at an entirely new concept in stand-alone engine-management systems offered by AEM. "Oh, an import company," you say. Well, yes, AEM's corporate history does run strongly through the sport-compact world (all the way back to an association with Redline and Weber carburetors if you want to continue that line of thought). This sport-tuning background hasn't hurt AEM in an engine-management sense, as making sequentially turbocharged, double-overhead-cam sewing machine engines run in the eights is at least as difficult as getting our adequately-sized units to do the same. Furthermore, AEM is not a couple of 20-somethings squinting under a droplight in their mom's garage at whatever they can pilfer from a RadioShack dumpster. Thanks to sales of various bolt-on and management bits, AEM has the resources to hire qualified engineers and to support an R&D facility to prove its designs.

What makes AEM's Plug & Play engine-management system different is the company's philosophy of keeping the entire host car's sensors and wiring, and changing only the computer itself. This means you can basically put away your soldering gun and wire crimpers, as there is precious little wiring to string. That also means the excellent factory wire connections are not broken, the stock connectors are retained, and dependability stays at the gravity and sunrise levels of consistency of the factory system. The underhood cosmetics even remain stock, if that's your thing.

It's also worth noting that a comprehensive system such as this is ultimately less expensive than going the usual piecemeal route. With the AEM computer there is no need to buy a separate boost retard, a separate datalogger, a separate two-step timing control, and so on. All those functions are incorporated into the AEM ECU.