5.7. Check and replacement of the sensor of impulses and block of control of ignition (TCI system)
The schematic image of components of ignition of engines with the TCI system
The sensor of impulses (it is located in the ignition distributor) and the coil of ignition needs check if in spark plugs there is no sparking. Be convinced of serviceability of wires of spark plugs, the coil and spark plugs (look the Sections Check and replacement of the coil of ignition and Check and replacement of sensors of ignition (Motronic system)). There are two types of blocks of control: Bosch and Siemens/Telefunken. Both types can be distinguished on electric sockets. In the lower part of the Bosch block one big rectangular socket while in the Siemens/Telefunken block two round electric sockets in its forward part are used is installed.
Check
Power supply and grounding of the block of control of ignition
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- At the switched-off ignition disconnect sockets of cables from the block of control of ignition. Connect the voltmeter between contacts 2 and 4 sockets of the Bosch system or between contacts 6 and 3 Siemens/Telefunken systems.
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- Include ignition. On the specified contacts tension has to appear. If there is no tension, then check wires for existence of breaks (watch the Head Sistem of onboard electric equipment).
- Ohmmeter check existence of connection between contact 2 sockets (Bosch) or contact of 6 (Siemens/Telefunken) and the case of the car. There has to be a short circuit.
- Ohmmeter check existence of connection between contact 4 sockets (Bosch) or contact of 3 (Siemens/Telefunken) and contact of the 15th coil of ignition. There has to be a short circuit.
- If indications wrong, repair a cable.
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Signal of the sensor of impulses
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- If tension comes to the block of control of ignition, check transfer from the sensor of impulses of alternating voltage to the control block.
- For the following tests use the digital voltmeter:
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- In the Bosch systems connect the positive probe to contact of the 5th socket, and the negative probe - to contact 6.
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- In the Siemens/Telefunken systems connect the positive probe to contact () the small socket, and the negative probe - to contact (-).
- Let the assistant a starter will turn the engine, at the same time check presence of alternating voltage from 1 to 2 Volt. If tension is absent, check a cable between the sensor of impulses (in the ignition distributor) and the control block. If a cable as it should be, check resistance of the sensor of impulses.
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Do not include a starter for long time. If necessary, to stop supply of fuel in the engine, disconnect the electric socket of an injector of cold start. |
- For check of resistance of the sensor of impulses act as follows:
- Measure resistance between contacts in Bosch blocks 5 and 6. The indication has to make from 1000 to 1200 Ohms.
- Measure resistance between contacts of the smaller socket in Siemens blocks. The indication has to make from 1000 to 1200 Ohms.
- If indications wrong, replace the sensor of impulses. If values of resistance for the sensor of impulses correct, and tension of blocks of control (supply voltage and tension of a signal wrong, replace the control block.
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Replacement
Block of control of ignition
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- Make sure that ignition is switched off.
- Disconnect the electric socket(s) from the control block.
- Unscrew screws of fastening of the block of control and take it from a motive compartment.
- Installation back to removal.
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Special dielectric paste is installed in blocks of control Bosch between a back part of the block of control and a thermal radiator. In case of their separation (replacement or check) old paste should be removed and to clear a thermal radiator an emery paper number 180. Apply Curil K2 paste (Number Bosch 81229243). Instead of paste it is possible to use a silicone dielectric compound. This processing is very important for providing a long resource of these expensive components of ignition. |
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Sensor of impulses
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- Disconnect a negative wire of the rechargeable battery.
- Remove the ignition distributor from the engine (look the Section Removal and installation of the distributor of ignition).
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- Flat-nose pliers for removal of lock rings remove the lock ring holding a sensor rotor.
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- Two flat screw-drivers from the opposite sides pick up a rotor of the sensor and carefully remove it up.
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Insert screw-drivers as it is possible more deeply without bending of a rotor of the sensor. Influence only the strongest central part of a rotor of the sensor. In case of bending the rotor of the sensor should be replaced. |
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Make sure that at removal of a rotor of the sensor, the cylindrical pin did not drop out. |
- Remove fixing screws, a vacuum diaphragm and the basis from the electric socket of the sensor of impulses.
- Unscrew two screws of the vacuum proofreader and separate him from the distributor, having shifted down and having unhooked from a basis pin.
- Flat-nose pliers for lock rings remove the lock ring holding the sensor of impulses and the basis.
- Carefully remove the sensor of impulses together with the basis.
- Unscrew three screws and separate the basis from the sensor of impulses.
- Installation back to removal.
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Do not forget to establish the isolating ring between the coil of the sensor and the basis. It has to be centered before tightening of screws of fastening. Also it will be necessary to check / adjust an air gap if removal of a rotor of the sensor was made, or to come up against a situation of the wrong gap (look the Section Check and adjustment of an air gap (TCI system)). |
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