For Renault 2.2 Bosch L-Jetronic FIS 1985 thru 1989 The Electronic Control Unit (ECU) Location: The ECU is located on the floor of the cab under the passenger seat. It is contained in a metal box with a removable top to protect it from damage. A harness with a large connector plugs into the left side of the unit and connects it to the rest of the electrical/electronic components located at various places in the engine compartment. Function: The ECU gathers signals from its sensors, processes them and using this information, controls the injection time intervals and makes changes accordingly by controlling the electrical voltages inputs or pulses to the Fuel Injectors. The components supplying information to the ECU are: 1. The Airflow Meter located in the intake ducting downstream of the Air Filter to provide information relative to the air density, volume, and temperature of the airflow passing thru the meter. 2. The Ignition Coil which supplies engine speed data to the ECU by using the coilÕs primary winding tach voltage to determine engine speed. 3. The Coolant Temperature Sensor (CTS) which provides information needed for fuel enrichment during engine warm up. 4. The Throttle Position Switch (TPS) located on the shaft of the throttle plate provides signals to the ECU whenever the throttle is at Idle or at Wide Open Throttle. (WOT) The ECU uses this data to increase fuel flow to the engine by holding the injectors open for a longer time or decreases flow by shortenings the injector open time. Maintenance: Internal repair of the ECU is not recommended. If testing indicates a faulty/inoperative ECU, a new one can be obtained thru the authorized parts supplier. Replacement is accomplished by disconnecting the vehicle battery, removing the cover of the enclosure which is secured with screws, removing the ground screw from the left side of the enclosure, remove the ECU, disconnect the wiring connector on the right(outboard) side of the ECU. To install, reverse these steps. The CTS (see above) is screwed into the thermostat housing. Identified by rectangular plug with 2 connector pins. Do not confuse with the water temperature sensor for the water temp gage, which has spade type connectors (two female) Test with a VOM set to ohms. There is a chart with ohms/temp. values in the Engine Fuel System section of the book. This part should be available at your local parts house or from Mobility RV. Order by Bosch part nr. It works to provide data to the ECU by which should give a rich mixture for starting and leaning out the mixture for normal operation. If the CTS is defective, it can result in over rich conditions, the same as "choking down" a carbureted engine resulting in symptom of shutting down a short time after starting. Also check the tail pipe for dark, gasoline smelling smoke during start and run indicating an over-rich condition. Larry S.