Camshaft Position Sensor

What is a Camshaft Position Sensor all about ?
 
The camshaft position sensor monitors the position of the camshaft and reports that data to the car’s onboard computer system. This computer system works with sensors and other devices to keep the engine running. With data from the camshaft position sensor (CPS), the fuel injectors know when to fire.
 
When the sensor malfunctions, the computer does not know when to fire the injectors and may not fire them at all. The faulty readouts may also throw off spark timing, which will affect the car’s fuel economy. This sensor is used in conjunction with the crankshaft position sensor to control ignition timing. It is common for heat and oil leaks to cause this sensor to fail, due to where the sensor is located.

Symptoms of a Failing Camshaft Sensor
 
1. "Check Engine" Light
The first symptom of a failing camshaft sensor manifests as a warning from the car’s control module. As the camshaft sensor fails, the computer sends the driver a warning sign via the “check engine” light on the car’s dashboard. When the check engine light first comes on, the driver has enough time to service the car and replace all faulty parts, including the failing camshaft sensor. However, if you ignore this flashing light for a considerable time, it could later lead to severe engine trouble. 
 
2. Disrupted Driving
Another symptom of a failing camshaft sensor is experiencing constant disruption while driving. If you are experiencing symptoms like frequent stalling, poor idling of the car at 500 to 600 rpms, a massive drop in the rpms slowing down the car to a crawl, a noticeable drop in engine power, poor mileage, abnormal acceleration activity, frequent stumbling, etc., it probably means you have a failing camshaft sensor that needs immediate attention. If you are experiencing these symptoms, it is best to seek a mechanic before the situation gets worse and the car gives up, refusing to start at all.
 
3. Ignition Trouble
If you ignore all of the above symptoms, you end up with one that really can’t be ignored—no ignition. Remember, as the sensor begins to weaken, so does the signal it transmits to the car’s computerized control station. If you let the problem carry on for too long, the engine will suffer from a “no spark” situation. Once the signal switches off, so will your engine, thereby stranding you. Thus, it is best not to let your car get to this stage.

How test the camshaft position sensor ?

Before testing any electrical component, inspect the wiring and connectors for damage. Also wiggle the connectors to ensure that they are firmly engaged. For this procedure a dwell meter, or the equivalent, will be needed.
 
1. Unplug the Camshaft Position Sensor (CPS) connector.
 
2. Turn the ignition ON .
 
3. Using a voltmeter, measure the voltage from the wiring harness connector 8-volt supply circuit (orange wire) to ground :
                - If the voltage is 8-9.5 volts, skip to the next step.
              - If the voltage measured is lower than 8 volts, or greater than 9.5 volts, the CPS is not receiving the correct current to function properly. There is a problem in the wiring or related components.
 

4. Turn the ignition OFF
 
5. Attach the CPS wiring and engine wiring harness connectors back together.
 
6. Attach a dwell meter to the battery. Attach the lead probe of the dwell meter to the sensor signal wire (light blue wire with dark blue tracer) by back probing the connector or by using jumper cables between the terminals. Refer to the accompanying wiring illustration.
 
7. Place the dwell meter out of the way of any moving components of the engine, and in a position in which it can be seen once the engine is started.
 
8. Turn the engine ON

9. Watch the dwell meter for one or two minutes while the engine is idling. The dwell time shown should be a steady 49-51%. If there is any fluctuation, or the dwell time is not 49-51% the CPS is defective and must be replaced with a new one.