I am sitting with a problem that is slowly draining my wallet. I drive a opel corsa utility 14i, and after having to replace a blown head gasket, all sorts of gremlins started popping up. First no fuel coming through, and after taking out the fuel tank and the pump, the pump was way under pressure so the pump got replaced. Now there is fuel and spark, but the car still wont run. It starts for about a second and then stops. Checked for loose connections and all that, and everything is fine. Then I decided to check the CPS (Crank Position Sensor). Starting on the ECU side I checked for voltages. The corsa uses a 3 pin arrangement, where pin 1 is the 5 volt supply line, pin 2 is the 12 volt signal line and 3 is the ground. I tested with the car switched on to where the dash lights come on, but not started. Now this is where I need help. The 5 volt supply reads about 5.2 volt, but the 12 volt signal gives 0.00 volt. Am I testing correctly or do I have a bigger problem?
Have you plugged it into a scanner to see if there is any fault codes and to look at the live data? Without doing so you're just stabbing in the dark and possibly wasting time.
Running only for a second or two can be symptom of a immobiliser fault. Have you swapped the ECU, Instrument Cluster or any other electrical component recently?
There is a common fault with petrol Corsa C's where the internal 5V circuit in the engine ECU fails. To eliminate this you can load test every 5V output on the ECU or send the ecu for testing at a specialist.
You haven't said what year which doesn't help
On ckp sensors I've always tested to make sure the supply wire does indeed have voltage (usually 9-12v). Make sure the ground is indeed grounded. On a 3-wire that third wire would then be your signal. You need to pierce that wire (back-probe) with the connector plugged into the sensor. While cranking engine you should be seeing an ON - OFF voltage equal to supply voltage. Like stated earlier, if you have spark, the ckp sensor is good.