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If the CPS is not delivering a useful signal, the ECU does not even know that you are trying to start the engine. When it gets that signal it closes the fuel pump relay. When the ignition is turned on, the ECU runs the pump for about 2 seconds. The fuel pump relay energizes the fuel pump fuse. So when cranking, if you see voltage at that fuse, the ECU sees the CPS working.
If you turn on the ignition and sweep through to the starter, the running of the fuel pump then many have nothing to do with the CPS working or not. Turn on the ignition, hear the pump run then stop, bump the starter and release and listen for the pump or monitor the voltage at the fuse.
CPS failures are typically seen as failure to hot start, but start cold OK. So that is an anomaly in the guess that the CPS is the problem. You can follow the CPS wire and find the connector. Inspect for contamination or wire damage (mice?). You can check the resitance of the CPS.
If you determine that the fuel pump is running while cranking, then you should expect to smell fuel at the exhaust or on the plugs if you pull them.
Read below about the CPS not triggering fault codes. That is because the ECU does not know that engine is been cranked. If the CPS went unreadable when the engine is running, then one could expect a code.
In Jun 03 Swedecar reported:
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Have the "techs" drive the car until really hot and then measure the resistance over pin 1-2 on the CKP sensor.
The resistance should be about 860 Ohm +-90 and if the reading is way over that when hot, the sensor is bad.
Very rarely does the sensor log a fault code when going bad even though it is a code specifically for that symptom.
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, Sun, 18 Dec 2005 09:19:21, Sun, 18 Dec 2005 11:22:40, Mon, 19 Dec 2005 08:25:52
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