If the engine jerks or stalls at idle, the cause may lie in a defect in the crankshaft position sensor. To check, start the engine and pull the wires at the sensor connector in different directions. If the engine stalls, replace the connector.
If the engine does not start, pull the cable at the connector while the starter is running. If the engine starts and stalls again, replace the connector.
Turn the engine over with the starter. If the tachometer does not show the number of revolutions, there may be the following failures: a defective crankshaft position sensor, a broken toothed belt, a failure of the ignition coil or a powerful buffer transistor.
Disconnect the plug connection of the crankshaft position sensor at the mudguard. Connect a voltmeter to pin 2 of the cable part of the connector and ground, see fig. K-2210. Turn on the ignition. Required value: battery voltage, approximately 11-13 V.
Connect the positive lead of a voltmeter to pin 1 and measure the voltage at this pin of the crankshaft position sensor connector. Required value: 4.8-5.2 V, in case of deviation, check the quality of the mass.
Check the quality of the mass. To do this, switch off the ignition and connect an ohmmeter to pin 2 and ground. The required value is 0 ohm.
Connector pinout differences:
- engine 1.5 l, release from 9.88 to 8.90: power supply = pin 3; ground = pin 2, output = pin 1
- 16 valve engine, from 9.88 to 8 90: power supply = pin 2; ground = pin 1, output = pin 4.
- 16 valve engine, build 9.90 to 292 supply = pin 3, ground = pin 4, output = pin 2, see also connector (IN) in fig. K-2210.