Check to see if the wiring is damaged.
The crankshaft sensor in your 1990 former Roche is located on the front of the engine. The best way to test your crankshaft sensor is to hook the engine to a Dyno tester.
It could be bad with out turning the light on.
check the front of the engine at the bottom for an electrical plug
the crank sensor is on the passenger side of the car on the back of the engine. Check right up there by the transmission housing.
Faulty sensor get it replaced if not check to make sure wire isn't shorting out
Check the crankshaft sensor. If the sensor on the Grand Voyager is bad then there wont be any spark.
Check the crankshaft sensor. Also check the timing and timing belt. The backfiring indicates that the engine is firing at the wrong time.
The check engine light will illuminate with a code(s) directing which O2 sensor is bad.
Check the crankshaft sensor. The sensor connector could be loose or the sensor could be bad. Try to read the engine codes to see if the computer shows an issue.
Need to know what code(s) were set and which O2 sensor you changed in order to help you.
check the crankshaft sensor or the cam sensor.
check crankshaft sensor sensor