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Right, so, I have a 96 Legacy Outback, 2.2 liter 5 speed. 274K on the clock. I will be making a very long story short. So please ask anything I may leave out. This all took place over the course of a few weeks. 

-Car randomly wouldn't start, after some time and a check engine light, it started. I had the codes read. P0340, Cam sensor fault code. 

-let it act up again with the same code.

-after some research, I started with the cam position sensor. The car started, I went about my day.

-random no start again. This time, cam and crank sensor fault codes came up. bought a crank sensor, car started before I put it in. 

-random no start once more, install the new crank sensor, car started later than normal, but started. 

-both cam and crank sensors are new now. The car is now not starting again, within ten minutes of the crank sensor install. Only this time, its not starting at all. Trying it a few times over the course of 2 hours or so.

When it starts the car runs flawlessly. No knocks, makes good power, idles smoothly. So it really feels like an intelligence/electrical problem. Either way, I am stumped now. Anyone heard of this at all? Any suggestions?

 

(I copy pasted this from my post on LegacyGT, for those of you noticing my whoring around)

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Yes, the whole engine harness unplugs at the bell housing. Makes for very easy engine removal.

Not a common issue but dirt/moisture can get in there, and if the connectors have ever been apart they may not have been clicked together all the way.

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Hmm, well in my care they have never been apart and based on known history of the car, they likely never have been. I am trying to get my hands on a code reader because it wont start so I can get it to Auto Zone or whatever. still on the search!

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timing belt seems unlikey, i would think you'd have other issues but the cam and crank sensors do share the timing belt to keep them in time.

 

that said - i have a previous thread from earlier this year about a 1999 2.2 liter with a bizarre cam sensor issue i couldn't ever track down.  i still don't know exactly what the deal was with that engine.

that engine ended up blowing up and i installed a new engine for him, that took care of the problem. lol

 

you might want to see that thread and see if anyone makes any suggestions there.

 

and i'll just own up and say i've done this before - you're absolutely positive that when you remove the cam and crank sensor you actually installed the new one and didn't accidentally install the same one back in place?

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Yea, I don't think its a timing belt issue, it runs like a champ once it starts. All the same power it had before, sounds and feels the same. Now, it's funny you mention that new versus old part bit. Because I panicked because I thought I did that. However, the old parts were red plastic and new parts are black plastic. The parts on the car now are black plastic. I have been thinking about it being an ECU failure of some kind, but I have just never heard of a Subaru ECU failing. 

 

I have also thought about junk floating around and blocking what the sensor is reading? Does that seem reasonable? I am just stretching right now because everyone I talk to so far is as confused as I am. 

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Yea, oil leaking from the oil filler where it connects to the valve cover, along with a few other places. 

 

It's very possible that you have oil leaking from the front cam seals & crank seal.  If this is the case your getting oil in the timing belt cover which can easily interfere with a cam sensor.

 

The problem is if you pull the new cam sensor since it hasn't been starting you should be able to see a "little" bit of oil at least on it causing this issue.  With my OBS the PS fluid would eventually drain off (since the cam sprocket was spinning) and run fine.

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Well in a "I have nothing better to do today, and trying nothing is annoying me" effort I have pulled off the cam gear covers to have a look at timing. (and everyone keeps suggesting it, though I really doubt its a timing issue. Car runs well when it runs) I don't see evidence of an oil leak from those places. We did the timing belt and the associated seals not too long ago, inside of 15K roughly so I believe that to be in good shape. I believe most of my leak is from the rear main seal and the filler neck o ring. However, I have had these sensors out a few times and have wiped them off each time. They haven't been particularly dirty, a spec or two here and there.

 

I wonder if theres something floating around inside the hole the sensors sit in?

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The crank sensor reads from the crank timing sprocket, cam sensor from the cam sprocket.

 

You won't likely get codes for these sensors if there is an obstruction or weak signal. The signal usually has to be totally lost (ECU thinks the sensor is unplugged) to set a code for these.

 

If it's not the sensors themselves, it could be loose terminals in the connectors, or it's going to be a wiring issue somewhere between the sensor and ECU.

The wiring runs beneath the intake manifold, has the manifold been removed for any reason recently?

Any evidence of mice?

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Mhmm, Mhmm. So thats that then, I see no evidence of mice anywhere. I have been in the engine compartment a few times (hill assist cable replace, valve cover gaskets, random things here and there) and have seen nesting materials, nothing like that so I believe it to be mouse free. The interior never has signs of rodents either. The manifold has not been removed at all in my care (about a year) and I dont believe it was with the previous owner either. The records I have show no reason for it to be removed. 

 

I am currently looking into timing, though I struggle with the theory because in between these codes the car would run great. Random no start condition.......Although now, its not running at all.....so....

 

two things, one, I believe this to be a non interference engine, is that correct? Two, at top dead center, the crank pulley hash marks should line up with the 0 degree mark on the engine and then the cam sprocket hash marks should be aligned with the notches in the rear timing cover. Right?

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No. Timing mark on the crank is on the back edge of the crank sprocket. It lines up with a notch in the oil pump housing in the center of the crank sensor.

 

Line that notch up, and the cam sprocket notches should be lined up with the notches in the cover.

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Ok, so I did that stuff and got the tensioner back on it. I left the rest of the nose of the engine apart and tried to start it. It didn't. Now, I struggled with the drivers side cam sprocket for a bit trying to get it lined up, it is right at the point of compressing some valve springs so it is hard to get just right. It is maybe the width of the hash mark off from the notch. I figured that wouldn't have that much of an effect on the car running but am I wrong? Maybe even those codes stored making it not start?

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No signal from one or the other and the engine won't start. ECU needs input from both to determine spark timing and fuel injection.

 

As I said before, if you have a code for either one of these sensors, it's because the ECU thinks it's not there, as in not getting any signal at all, as if the sensor is unplugged.

Poor connection at the sensor(s), at the large connectors on the bellhousing, or a wiring issue.

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Ok!  Scooberoo and everyone else, you have been tremendous help. I have what I hope to be a final update in this saga. 

 

So after all that business, after it wouldn't start once I got the engine back in time and it wouldn't start, You're all going to love this, I put the old cam sensor back in it just on a whim and the car started immediately and has started 4 times or so in a row since then. I have warrantied the sensor and I am waiting for a new one, should come in tomorrow. Now all this means I should be Ohms testing the sensors. Does anyone know what value I should be getting from a good working cam or crank sensor?

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"3. CHECK CAMSHAFT POSITION SENSOR.

1) Remove camshaft position sensor.
2) Set the position (+) probe at sensor connector terminal
No. 1, and set earth lead at terminal No. 2.
3) Check that a wave profile appears crossing a magnet
near the pick-up coil of crankshaft position sensor."
 
That's from the FSM for my '96 OBS for testing the cam position sensor, but you would need an oscilloscope to test it.
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