Engine Maintenance and Modification Bradley Artigue

FIAT 124 Spider
Engine Maintenance + Modification
5. Fuel Injection
FIAT Spiders manufactured from 1967 through 1978 were equipped with carburetors.
Vehicles manufactured from the 1980 model year through the end of production in 1985
were equipped with electronic fuel injection. There is some argument about the
transition from carburetion to fuel injection. The most plausible story is that FIAT first
offered fuel injection as an option, then as standard equipment in California, then as
standard equipment for the entire line. Regardless of when or why you can always tell
what system your vehicle had installed by looking at the body style number. This is the
first four or five positions in your vehicle’s VIN number. The VIN is stamped in your
engine compartment, on a small metal plate on your dashboard (near the driver’s side
windshield), and on some models inside the driver’s side door. The first three positions
will read “124” or (on later vehicles) “ZFA124”, followed by a two letter “primary” body
code.
AS, BS, CS1, CS2:
CS0, DS:
VX:
Carburetion
Fuel Injection
Carburetion / Supercharger
Fuel injection systems were provided by Bosch GmbH (“Bosch”). Carburetion and fuel
injection approach mixing fuel and air in very different ways. Simply put, a carburetor
mixes fuel outside of the combustion chamber. The mixture is drawn through a plenum
into the combustion chamber. In a carburetor the settings that govern the mixture of
fuel and air remain relatively static, fixed mechanically by the jets and orifices in the
carburetor and when the vehicle is tuned. A fuel injection system sprays metered fuel
directly into the manifold at the intake port during the intake cycle. The Bosch system
used in a FIAT electronically controls the amount of fuel, resulting in more dynamic
control of air to fuel ratios.
By the end of the 1970’s fuel injection systems were slowly overtaking carburetion on
the drawing boards of automotive engineers. Driven by emissions control regulations
and a noticeable improvement in performance and fuel economy, fuel injection was
evolving from complex mechanical systems to electronic “engine management”
systems. The Bosch L-Jetronic system was used on the majority of European fuel
injected cars, including FIAT, Alfa Romeo, Ferrari, Lamborghini, Lancia, BMW, Mercedes,
Porsche, Renault, Volkswagen, and Peugeot. It was preceded by a number of
mechanical systems, including the K-Jetronic by Bosch and mechanical systems by
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