The New Renegades: Back-Yard Engineers

Major automobile producers have invested billions of dollars to develop electronic engine controls to improve engine efficiency, reduce emissions and boost performance.

These computerized engines have one thing in common: They remove the car owner’s ability to tune his own engine.

For all practical purposes, the engine’s tuneup parameters--including ignition timing and fuel mixture--are controlled by software programmed into a central computer.

But recent evidence shows significant public tampering with these engine controls, motivated by efforts to improve on their engine performance or to simply solve an intractable problem.

Open any hot rod magazine and you will find advertising for cheater chips, computer memory chips that alter the original factory specifications that control the engines.

The use of these chips violates many federal and state laws, but they are none-the-less widely used.

An estimated 35 million vehicles, including those with computer controls, have had their emissions systems tampered with, according the public interest group Concerning Cars.

By and large, this tampering occurs with older cars, which have had catalytic converters removed or incapacitated.

But it also includes a new breed of car enthusiasts who are far more sophisticated than the Saturday afternoon, back-yard mechanic who used to tune up the engine.

Tom Evernham, director of engineering at General Motor’s Delco Engineering Corp., calls these new car buffs back-yard engineers, because it requires a fairly high level of technical sophistication to tamper with the computer control system on most new cars.

“I realize the frustration of car buyers who can no longer change the parameters that affect the function of their engines,” Evernham said. “But this is critical to the industry and to the safety of the public.”

By tampering with a single engine computer, a car can blow emissions equal to what 100 cars would generate. And yet, it is difficult to estimate how much additional performance hot rod enthusiasts get from a cheater chip.

“I don’t think we are talking about 50%,” he said. “Maybe 10% more power, but that could mean the engine is only good for 10,000 miles. If we let the renegades do whatever they want, then why are we as a society going to all this trouble for the common good?”

It is difficult for even experts to say how much computer tampering is occurring. Probably most Cadillac or Lincoln owners don’t tamper with their computers.

But on sports cars like a Camaro or Mustang, it’s a different story.

The engine computer itself is typically in a box about 8 inches long, 5 inches wide and 1 inch thick. The software that controls any particular engine is contained in a programmable read-only memory chip, which allows each computer to be tailored to a car’s weight, engine size and other options. The software is the engine’s recipe for engine timing, idle speed and fuel mixture. It constantly adjusts these parameters based on electronic sensors that report the outside air temperature, the engine’s speed and the vacuum level inside the intake manifold.

The software will tell the engine’s coolant fan when to turn on. By altering the software, an engine can be made to run hotter or cooler, according to one expert at a company who sells these chips.

Software also controls the speed at which the transmission shifts to the next higher gear, so a performance buff may change the shift points. By next year, some manufacturers will begin to seal their computers in steel boxes to discourage tampering.

But don’t worry about the outlaws. The firms that make outlaw chips are preparing to build entire outlaw computers.