The Brilliant and Doomed Pioneer of Fuel Injection
The Bendix Electrojector was comically expensive and desperately ahead it's time.
Steven Wilson
The Fifties were an age of intense progress for the auto industry. Technological advancements arrived at a gallop, making up for time lost to the war. And as with superchargers before, an exotic aviation technology found its way into our cars: fuel injection. The evocatively named Electrojector was the world’s first automotive electronic fuel-injection system, introduced by the Bendix Aviation Corporation in 1956, a time when computers were roughly the size of small buildings. It was brilliant—and an almost complete failure.
Advertisement - Continue Reading Below
This story originally appeared in Volume 6 of Road & Track.
SIGN UP FOR THE TRACK CLUB BY R&T FOR MORE EXCLUSIVE STORIES
The Electrojector was cutting-edge, developed from Korean War aircraft tech. A triggering selector—essentially a second distributor with two sets of points—worked with what Bendix called an electronic modulator. It’s a computer in everything but name. But if you take one apart, it looks more like an old radio, a tangle of transistors, waxed-paper capacitors, and resistors. Two throttles sit above the intake manifold. Attached to the primary throttle are temperature, cold-start, manifold pressure, idle speed, and acceleration sensors. The triggering selector sends electric pulses to the modulator box, which modifies them based on information from the sensors. Those pulses, of varying lengths, tell the eight fuel injectors when to open and for how long. The modulator even compensates for altitude. If this sounds like modern electronic fuel injection, that’s because it basically is, just built with Fifties hardware.
Advertisement - Continue Reading Below
A. Primary throttle body
B. Temperature sensor
C. Pressure regulator filter and vapor separator
D. Triggering selector unit
E. Modulator unit
F. Fuel pump
G. Cold-start and warm-up sensor
H. Manifold vacuum sensor
I. Idle sensor
For the 1958 model year, the system was offered on high-end Plymouths and Dodges, the De Soto Adventurer, and the Chrysler 300D. It was comically expensive, adding as much as $637 to the price, a helluva lot of money in 1958, especially for something that didn’t work very well.
Tom White of Whitehall Auto Restorations in Hopkinton, Massachusetts, reckons he’s worked out all the Electrojector’s problems.
“This system, at 50 degrees, would blow the doors off anything on the road,” White says. “It was phenomenal.” Unfortunately, it didn’t work so well in hot weather. Owners complained of their cars running poorly and stalling.
Advertisement - Continue Reading Below
Those problems would be easy to fix in a carbureted car, but were tough to solve with the Electrojector. Just 35 cars were ordered with the system, and Chrysler recalled them all.
“They washed their hands of it totally, because basically, think about it: 1958, who in God’s name could service that vehicle?” White says.
In the Nineties, White acquired the first De Soto Adventurer convertible ever built, which left the factory with fuel injection. By chance, he met someone friendly with a tech who took the Electrojector system off a De Soto in the Fifties and stored the parts. White, formerly an electrical engineer at Raytheon, bought and restored the system.
He found that the original electrolytic capacitors in the modulator had drifted over time—a phenomenon tube-amp enthusiasts are familiar with—so he replaced them with modern units. He suspects, too, that Bendix got the value of one capacitor wrong. The altitude compensation system was limited, requiring adjustment for location.
Advertisement - Continue Reading Below
JOIN NOW
White tuned the system on a bench rig, spinning the triggering selector unit with a drill and listening for air coming from each injector. The process took six weeks. Once the system was working, White installed the system in the De Soto as part of a concours-quality restoration. The car was sold, but to this day, it’s the only Mopar running a Bendix system basically in factory spec.
After Chrysler recalled the system, Bendix licensed it to Bosch. Then, in 1967, Bosch introduced D-Jetronic, largely an improved Electojector. D-Jet was a precursor to modern EFI systems, including the widely used Bosch Motronic. Despite its failure to break through, the Electrojector was a work of genius, but perhaps one that arrived a decade ahead of its time.
