Crankshaft speed sensor
Removing
1. Disconnect the negative battery terminal.
2. Disconnect the sensor wire from the harness on the connector, which is located in the engine compartment behind the battery.
3. The sensor is located on the mating surface between the cylinder block and the clutch housing, above the starter hole. Loosen the mounting bolt and remove the sensor from the clutch housing. Remove the metal bushing where it is installed.
Installation
4. Installation is carried out in the reverse order. Where provided, ensure that the sleeve is installed before inserting the transmitter into the housing.
Electronic control unit (ECU)
Removing
5. The ignition system control unit is located on the left side of the engine compartment on top of the inner wheel arch (see fig. 7.5, a, b).
Pic. 7.5, a. Location of the electronic ignition control unit (shown by arrow) - models with TSZ ignition system
Pic. 7.5b. Location of the electronic ignition control unit (shown by arrow) - models with EZL ignition system
6. Disconnect the negative battery terminal.
7. Disconnect the multi-pin connectors from the control unit, labeling each so as not to confuse during installation.
8. Disconnect the manifold vacuum hose from the fitting on top of the control box. Plug the nozzle so that dirt does not get into it.
9. Turn away nuts of fastening and pull out the control unit from a motor compartment.
Note: A heat-conductive paste has been applied to the bottom of the control box to improve cooling - try not to stain the surrounding parts with the paste. Do not remove protective spy.
Installation
10. Installation is carried out in the reverse order. If the contact paste layer is dirty or has hardened over time, purchase the required amount of paste from a Mercedes-Benz dealer and reapply. Check that the protective layer is correctly applied.
Coolant temperature sensor
11. Where provided, the ignition system and the fuel injection system share the same coolant temperature sensor - refer to the relevant part of Chapter 4 for information.
Throttle position sensor
12. The ignition system has one throttle position sensor common with the power supply system - refer to the information given in the relevant part Chapters 4.
Intake air temperature sensor
Removing
13. The intake air temperature sensor is located on the side of the air cleaner housing.
14. Make sure the ignition is off. Then disconnect the sensor wires at the connector.
15. The sensor has a connection type "bayonet" - squeeze the tabs of the clamps, turn a quarter of a turn and remove it from the air cleaner. Remove seal.
Installation
16. Installation is carried out in the reverse order.
TDC position sensor
17. The TDC sensor is located on a bracket above the crankshaft vibration damper at the front of the engine. Installing the sensor with the bracket in relation to the end of the vibration damper is critical to the operation of the ignition system and requires complex installation steps. For this reason, this work is recommended to be carried out at a service station.