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k-jetronic(CIS) continuous injection Posted by DougM [Email] ![]() ![]() ![]() In Reply to: D-jetronic(electronic) injection, DougM ![]() ![]() |
K-Jetronic/K-lambda Jetronic ("CIS")
"Jetronic is commonly referred to as "CIS", or "Continuous Injection System", due to the mechanical fuel distributor. The "K" in K-Jetronic indicates continuous injection, and "lambda" indicates the inclusion of a lambda probe, or oxygen sensor on certain models. The oxygen sensor computer is wired differently in both models. Operating theory is very basic. The engine sucks in air, which raises the fuel distributor vane meter, thus metering fuel (continuously) to the mechanical injectors. Models with an oxygen sensor have the air/fuel mixture controlled by a frequency valve that lets in extra air to lean out the mixture when needed. There is no knock control."
CIS replaced d-jetronic in 1975, a few reasons for the change were stricter EPA emissions requirements and system reliability. Some have claimed the system so reliable that only fuel filter changes were needed every 30k miles or so. Buying one that's been sitting for many years is something to consider. Old fuel gums up the fuel tank, fuel pump, fuel lines, injection distributor, and injection valves, and fuel lines get brittle, so reliability won't be restored until all issues are resolved.
Replacement parts can be difficult to source for d-jet or k-jet, and could be quite expensive if found new.
posted by 75.187.23...
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