The crank sensor test itself is pretty easy, since the sensor is a two wire type.
What is difficult is getting to it, since you'll have to jack up the vehicle (and place it on jack stands) and remove the passenger side wheel to get to the crank sensor.
The following test instructions assume you have already done all of this leg work.
One last thing before we start: Remember... if you've got spark coming out of at least one spark plug wire.... this tells you that the crank sensor is producing a signal and functioning correctly and this test will not help you. For more info on this, take a look at the section: Symptoms of BAD Ford Crank Sensor.
OK, this is what you need to do:
After jacking up the vehicle (and placing it on Jack Stands) and gaining access to the crank sensor.
Unplug the crank sensor from its electrical connector and remove some of the plastic wire loom protector and/or the black electrical tape that shields/protects the two wires of the CKP sensor.
Since you need to access the signals inside the two wires, you'll need to use a wire-piercing probe or another appropriate tool, to probe the number 1 and number 2 wires of the crank sensor with the multimeter leads.
To see what a what wire piercing probe tool looks like, click here: Wire Piercing Probe.
It doesn't matter which multimeter lead (RED or BLACK) goes where, since the polarity of the leads doesn't matter.
Reconnect the connector to the crank sensor now and turn the multimeter's dial to Volts AC.
Make sure your multimeter test leads (and wire piercing probes) will not interfere with the crank pulley or the serpentine drive belt, since you'll be cranking the engine.
When all is ready and you're a safe distance from the engine, have your helper crank the engine (as you observe the multimeter).
If the CKP sensor is OK, you should see a voltage constantly jumping between .5 to 1 Volt AC while the engine is cranking and 0 Volts AC with the engine not cranking.
Now, to be a bit more specific: your multimeter will not register a steady AC voltage. Instead, the reading will jump between .5 Volts AC to 1 Volt AC continually as the engine is cranking and only when the engine is cranking.
OK, let's interpret the multimeter test results you just obtained...
Alright, let's find out if you have a BAD CKP sensor on your hands or not. Choose from the CASES below that best match your specific results:
CASE 1: The multimeter registered the indicated AC voltage with the engine cranking: This result indicates that the CKP sensor is creating a good CKP signal and is working fine.
CASE 2: The multimeter DID NOT register the indicated AC voltage with the engine cranking: This confirms that the crank sensor is fried and is the cause of your Ford's ‘cranks but does not start condition’.
You can find the crank sensor just about in anywhere. The best place to buy it is is online.
The following links will help you comparison shop for the crank sensor:
Not sure if the crank sensor fits your particular Ford/Mercury? Don't worry, once you get to the site they'll make sure it fits by asking you the specifics of your particular Ford vehicle. If it doesn't fit... they'll find you the right crank sensor.
You can all of the 1.9L, 2.0L Ford tutorials here: Ford 1.9L, 2.0L Index of Articles.
Here's a sample of the tutorials you'll find in the index:
“For instance, on the planet Earth, man had always assumed that he was more
intelligent than dolphins because he had achieved so much —the wheel,
New York, wars and so on —whilst all the dolphins had ever done was
muck about in the water having a good time. But conversely,
the dolphins had always believed that they were far more
intelligent than man —for precisely the same reasons!”
The Hitchhiker's Guide to the Galaxy