Need instructions for testing Crank and Cam Sensors, Got specs

[Telltell]

Hey guys,

I already tested the harnesses and they were good. I have the specs for testing the Crankshaft and Camshaft Sensors themselves for my 96 N/T, but need to know HOW to test them. Your help is appreciated.

Specs, coming form this thread:
http://www.dsmtuners.com/forums/420...g-think-ecu-since-its-95-a.html#post151874377

Now I want to test the Sensors themselves, but i may be doing it wrong.

I tried testing the pins coming from the sensors [[with the harness disconnected]] but i get no voltage reading on any of the pins. --- so i think this is wrong

One option I'm thinking is to test these voltages by leaving the sensor and the harness connected.
But How?
Test the wires on the connected harness by poking a hole with the mulitmeter terminal and making a connedtion like that, and the other mulitmeter terminal to a metal bolt to create ground??

I'm just not sure.

Thanks a lot guys!

 

[urmomsaniceguy]

Its not voltage you need to test on the sensors its the resistance in OHMs. Turn Your Voltmeter to the Ohms section and test. As for Specs not sure.

 

[VelocitàPaola]

Its not voltage you need to test on the sensors its the resistance in OHMs. Turn Your Voltmeter to the Ohms section and test. As for Specs not sure.

No, both sensors are Hall effect sensors, there's no particular resistance for which to look. The output is a series of pulses, either 0V or 8-12V. With your multimeter connected to the signal pin of the sensor, you should be able to see the signal alternate between 0V and 8-12V if you slowly turn the rotating assembly by hand.

When the car is running, and the rotating assembly is spinning considerably faster, you should measure a voltage between the high and low voltage levels (probably around 4V to 6V). Most multimeters average fluctuating signals since the display would change too much to be readable, hence the reading of 4V to 6V.

 

[96TurboGS]

One option I'm thinking is to test these voltages by leaving the sensor and the harness connected.
But How?
Test the wires on the connected harness by poking a hole with the mulitmeter terminal and making a connedtion like that, and the other mulitmeter terminal to a metal bolt to create ground??

To test, you will need to locate the signal wire and place a probe on the signal wire and another to a good ground on the chassis. The signal wire should be yellow with a white stripe. Leave the wire connected, and shave some of the insulation away to expose the wire.

The pulses are a series of alternating 0-5v, its either 0 or 5v. 0v would reference the metal while 5v would reference the air gap (missing tooth). The volt meter shouldn't read higher then 5v if it's a good meter. I have a good ol cheep RadioShack one and cycles 0-5v on my car. If it's not cycling correctly or there isn't a pattern then you can rule out the sensor. (but will be harder to chase if you have a rough idle) However, the better way to test the sensor would be to look at the signal wire through an oscilloscope to view missing pulses while the engine is spinning at idle, but who does that?

 

[Telltell]

Thanks a lot Rafiel. This method is more what i was looking for. Ill try that.

Paul, I wasn't really understanding the rotating the assembly by hand. But thanks a lot anyway.

Thanks everyone.

 

[VelocitàPaola]

Hmm... maybe the sensors are different on later year cars. My crankshaft angle sensor outputs an 8V pulse.

Telltell, you won't be able to measure the pulses Rafiel is referring to with the engine running and the crankshaft/camshafts spinning. The output will get averaged by your multimeter; in other words, you'll measure something in between the high and low value (0V and 5V in your case). In order to really test the sensors without an oscilloscope you need to slowly rotate the rotating assembly; simply rotate the crank at the crankshaft pulley bolt using a socket wrench. This way, the signal will be slow enough for the high and low pulses to register on your multimeter.

 

[96TurboGS]

Telltell, you won't be able to measure the pulses Rafiel is referring to with the engine running and the crankshaft/camshafts spinning. The output will get averaged by your multimeter; in other words, you'll measure something in between the high and low value (0V and 5V in your case). In order to really test the sensors without an oscilloscope you need to slowly rotate the rotating assembly; simply rotate the crank at the crankshaft pulley bolt using a socket wrench. This way, the signal will be slow enough for the high and low pulses to register on your multimeter.

This is true; it's been a while since I've done it, since there are 2 other custom methods Ive constructed/use. At about 800 RPM's the idle is something like 100 ms per rev and about 6ms in between each pulse after the Sync tooth or TDC. A bit faster than what your average volt meter will show. I have made a circuit with a few simple LED's a while back that trigger whenever 5v is reached from the signal. It works well and there is a correlation/pattern that associates with it, I have diagnosed a bad sensor this way on my car before. Often, when a sensor is intermittent, there will be a loss signal for 100-500 ms then it will return back to normal. (i noticed) When I turned my crank slowly it seemed ok but at 800 rpms it was still missing, so I placed the LED's I built in and I could see where it was missing every other second. (During this time the pulse would stay high) Turning the crank and watching for the volt meter may work, but he would have to know how many times its suppose to go high in one rev (8 pulses). Sometimes it will appear fine when turning the crank but it's the higher frequencies that will determine if the sensor is efficient.

@Telltell: Ultimately, testing the crank sensor is hit or miss, you should rely on the computer to flag a pending DTC (although mine didn't), or you could buy one at the zone and if there is no difference take it back. It's fairly rare for them to be die without any kind of wiring problems/oil,water,mud in connector/being old.

 

[VelocitàPaola]

Telltell, the bottom line is that it's nearly impossible to diagnose an intermittent crankshaft angle or camshaft position sensor problem without specialized equipment or an oscilloscope. The factory service manual recommends the following procedure:

* Check the PCM for stored DTC's.
* If there are no DTC's, check the wiring harness for damaged wires/connectors.
* If the wiring harness is in good shape, replace the sensor.

So even Mitsubishi technicians don't fully test the sensors; they just replace them. The multimeter tests will just give you an indication as to whether the sensors are outputting any signal at all.

 

[Telltell]

Thanks a lot Paul. I hear you.