Cam Position Sensor issue

[emmasweeny]

After much research I beleive the reason my '92 is not starting is a bad cam position sensor. The CEL code is #12 but I have reason not to beleive it. I pulled the sensor out with no change in symptoms. The wiring has been spliced and I was wondering if anyone knew how to check to make sure the sensor is bad and not the wiring before I shell out two bills on a new one.
Thanks in advance.
Roy

[oab_au]

Originally Posted by emmasweeny

After much research I beleive the reason my '92 is not starting is a bad cam position sensor. The CEL code is #12 but I have reason not to beleive it. I pulled the sensor out with no change in symptoms. The wiring has been spliced and I was wondering if anyone knew how to check to make sure the sensor is bad and not the wiring before I shell out two bills on a new one.
Thanks in advance.
Roy

I guess you mean the code was a 13? as 12 is for the starter circuit. The cam sensor is not too easy to check, the book gives no resistance readings for it. You could check to see if the windings are open circuited, or shorted. Or you could check the output at cranking speed with a meter set to a low AC reading. It should show 0.1VAC at least.

These sensors have a magnet in them that can weaken with age to reduce the output. I would suggest you try a replacement. The Legacy sensor is the same.

Harvey.

[legacyau]

i had that code come up on one of my libertys once but it turned out that the fuel pump relay was dodgey but if you crank them too long it sets that code so make sure youve got fuel pressure or try squirting some into the manifold and cranking it then if it fires you have a solution

cam

[svxfiles]

Originally Posted by emmasweeny

After much research I beleive the reason my '92 is not starting is a bad cam position sensor. The CEL code is #12 but I have reason not to beleive it. I pulled the sensor out with no change in symptoms. The wiring has been spliced and I was wondering if anyone knew how to check to make sure the sensor is bad and not the wiring before I shell out two bills on a new one.
Thanks in advance.
Roy

Believe it or not, a water temp sensor can cause this code to show up.
Part #22630AA041
$27.77 list, 19.99 plus shipping from 1stsubau.com

Big thanks to Hocrest for this find.

[TomsSVX]

Originally Posted by legacyau

i had that code come up on one of my libertys once but it turned out that the fuel pump relay was dodgey but if you crank them too long it sets that code so make sure youve got fuel pressure or try squirting some into the manifold and cranking it then if it fires you have a solution

cam

Originally Posted by svxfiles

Believe it or not, a water temp sensor can cause this code to show up.
Part #22630AA041
$27.77 list, 19.99 plus shipping from 1stsubau.com

Big thanks to Hocrest for this find.

For the same reason... If the car does not start within a specified amount of time (not sure off the cuff) it will throw the code. Basically the ECU wants the engine to be running and if the rotation is too slow (cranking) for too long, this is what happens

Tom

[Trevor]

Message deleted as not applicable.

[LetItSnow]

Apologies for the old thread bump, but this is the first one I found that clearly involved the Cam Position Sensor.

I borrowed this diagram from Suby Fan:


It's the test for the cam sensor. I don't remember which way I had it wired (which was ground, and which was signal) but I don't know if it mattered.

What interested me was the test method, which was kind of vague. I didn't give it a full-on Hall Effect, just a proximity test, which isn't the way it's treated in the car. After testing the new sensor with the same methods, I found out that it didn't matter.

TEST: The old sensor showed a subtle wave without metal near, and it only left that when something was in contact with it... metal, magnet, ...even just my hand. The new sensor showed a flat wave without metal near, and it went crazy with metal or magnet within four to five inches, even stationary. From my experience, you really shouldn't have to wave a high-powered magnet within an eighth of an inch to get the sensor to notice.

It can also be said that, as obscure as they are, there's probably someone in your circles who has an oscilloscope.

Needless to say, my three-weeks-dormant SVX is ready for the race on Sunday.

[oab_au]

Using a magnet to test the sensor, really defeats the test. There is a magnet in the sensor, and that is the one that you must test, as it can become weaker with age and temperature.

If you connect a meter, set at a low voltage AC range, between the wires the polarity does not matter. Then move a metal object across the face of the sensor it should show a reading that becomes larger, the faster, you move the metal across it.

The book doesn't give any resistance readings for the winding, just that it should read at least 0.1V Ac minim, when cranking the engine over.

Harvey.