Lean Burn - Chrysler Electronic Lean Burn

Chrysler Electronic Lean Burn

From 1976 through 1989, Chrysler equipped many vehicles with their Electronic Lean Burn (ELB) system, which consisted of a spark control computer and various sensors and transducers. The computer adjusted spark timing based on manifold vacuum, engine speed, engine temperature, throttle position over time, and incoming air temperature. Engines equipped with ELB used fixed-timing distributors without the traditional vacuum and centrifugal timing advance mechanisms. The ELB computer also directly drove the ignition coil, eliminating the need for a separate ignition module.

ELB was produced in both open-loop and closed-loop variants; the open-loop systems produced exhaust clean enough for many vehicle variants so equipped to pass 1976 and 1977 US Federal emissions regulations, and Canadian emissions regulations through 1980, without a catalytic converter. The closed-loop version of ELB used an Oxygen sensor and a feedback carburetor, and was phased into production as emissions regulations grew more stringent starting in 1981, but open-loop ELB was used as late as 1990 in markets with lax emissions regulations, on vehicles such as the Mexican Chrysler Spirit. The spark control and engine parameter sensing and transduction strategies introduced with ELB remained in use through 1995 on Chrysler vehicles equipped with throttle-body fuel injection.