Volkswagen Golf/Jetta/Cabriole 1990-1999

Motronic System


The CIS-E Motronic system used on the 16 valve engines is yet another version of the CIS-E fuel injection system. The system uses mechanical injectors, a fuel distributor, fuel pump and air flow sensor that are similar to those on earlier systems. Most of the electronic system controls are also the same. The major difference that the Electronic Control Unit (ECU) now controls the ignition system as well as fuel injection. The new ECU is equipped with an adaptive learning program which allows it to learn and remember the normal operating range of the mixture control output signal. This gives the system the capability to compensate for changes in altitude, slight vacuum leaks or other changes due to things such as engine wear. Cold engine drivability and emissions are improved. The new ECU also is capable of cold start enrichment without the use of a thermo-time switch.

The fuel injector pressure is higher for better fuel atomization and residual pressure. The threads on the new injectors are different so they cannot be interchanged with older units. Some other components such as sensors are similar to those used on the Digifant engine management system. Some of the testing procedures are the same but the parts are not necessarily interchangeable.