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Saturn vue crank sensor

03 Saturn vue 3.0 v6. It’s an opel motor. Yep oddball.
Has had bi-weekly stalling issue for several months.
Would not start yesterday. Crank. Crank. Crank
It did have a throttle body circuit code a few months ago
No codes today.
Pulled crank sensor. Had metal filings on tip
Cleaned it. Motor ran. But I had maf unplugged and it stalled after 2-3 sec
Pulled sensor again and it had a bit more filings.
Cleaned it. Plugged in maf. Idles fine
I could not get plug off sensor. Greasy. And tight
So, motor runs. Does that mean sensor is ohm ok?
Sensor wire is “delicate”. Runs next to exhaust manifold. Plastic heat shielding is flaking off.
But insulation on 2 wires looks ok.

Tester

Can you tell where the metal filings are coming from? Maybe the sensor is too close to what it senses, or the thing that it senses is slowly dematerializing. Or maybe the sensor has somehow become magnetic and is attracting metal particles.

If I had a sensor that I couldn’t remove the connector – but could remove the sensor from the engine – I’d probably snip the wires and see if I could figure out a way to remove the connector on the work bench. Then I’d just solder up the wires again. There may be a braided or foil shield you’d have to re-splice too. Connectors that cannot be disconnected are frustrating and I’d just as soon have no connector at all than one I couldn’t undo.

got plug off. Sensor measures 1800 ohms. Should be 850 been told. So?

Not sure how the crankshaft sensor works, but the camshaft sensor is a hall-effect semiconductor device. Unlike a simple resistor or even just a length of wire, the resistance of a semiconductor depends on the voltage used to measure it. I expect the crankshaft sensor is a hall-effect also, which means its resistance will depend on the design of the meter used to measure it. If you are measuring 1600 ohms with your meter, it’s probably ok. The way to know for sure is to measure its voltage output as the engine turns w/an o’scope. From what I can see it would output a short 12 volt pulse 58 times per crankshaft revolution. A pro scan tool might be able to do that w/o using an o’scope.

I went to store and measured one and it was 900ohms. I assume computer only cares that sensor can see a difference when the crank swings by. Vs a failed sensor where it sees nothing. It sees hi/low or a change. Vs no change. Maybe
Crazy. Rock auto has sensors for $5, $20, $40, $80, Bosch which is oem is 60. Gm is similar.
Autzone is 115. Napa is 75

Some crank sensors are just a tiny coil of wire. It works sort of like an antenna, picks up the magnetic flux from the rotating component, induces an AC voltage in the coil. For that type measuring the resistance is a good test. The common failure mode – b/c the wire used is very thin — is the wire eventually breaks somewhere inside the coil, and you measure infinite resistance.

I don’t know what , if any, conclusion can be drawn from you measuring 900 ohms on a parts store part vs 1600 ohms on your part. I doubt that’s meaningful.

going to check boneyard for another sensor. i know our yard has at least 1 3.0 vue. and who would grab a crank sensor? at least measure it.

If there’s any doubt whatsoever . . . just buy and install a new sensor

did find an older thread on how the sensors work in the saturn vues and there was a mention of the fact that the vue only sees 2 pulses per firing sequence. So the instant the crank arm swings by the sensor the computer say oh, there it is.

No experience with this device, but at $50 the price is right. You could monitor the output signal from the crank sensor and get to the bottom of this pretty quickly I expect. Its 20KHz bandwidth would be too low for most electronics work, but should be fine for most automobile diagnosis applications.

If I had $50 burning my pocket, I would add $50 and bought a basic PICO scope.
On the downside, you need a laptop to connect it to.
On the bright side, you are talking not kilohertz, but tens of megahertz, triggered recording, multi-channel and many other useful modes.

I’d find it a little inconvenient to have to lug a laptop into the garage, plus I’d be concerned about damaging the laptop in the process. You could put the laptop on its own stand to protect it, but then you got a stand taking up space. A small hand-held stand-alone o’scope for garage use is what I’d prefer. I already have a 20MHz lab/bench o’scope , and I use it for my auto diagnosis/tune-up needs from time to time, but I’d prefer to have a stand alone cheapo for garage use, and keep the lab scope away from the garage.

I’ve just got the fourth laptop to my house…
My coworker was throwing one away and I took it specifically for car diagnostics, to attach to the USB adapter and run vehicle-specific software reading non-OBD data.
Now I do not care if I use it with dirty hands or drop it incidentally, this 5 years old beater seen it all :slight_smile:
A friend of mine spent $30 to buy one for the similar puropose at a local electronics recycle store.

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Replacement one is 900 ohms. Vue is running now. Went to store to use better code reader for abs light. No abs code. But it. Said I had crank sensor error in history. But no dash lights. Looks like a better code reader is worth having.