Cam Position Sensor issue

[charl]

Hello all,

It's been a few years since I've posted, but I have a new problem.

Tried to start my '92 subie legacy an hour ago and got an interesting sound.
No start and a 'skipping' sound from the engine. I'm getting what sounds
like compression on at least one cylinder and nothing out of the others. As
I crank the engine, the sound changes, as though I'm getting compression in
other cylinders. My first thought was a broken timing belt, but if that
were the case I don't think I'd be getting the changing sounds. On my last
crank one of the cylinders hit, but still no start.

I ran the OBD and it came up with error code #13, a cam position sensor.

What's up with this? Would a bad sensor screw me up that bad?

Any pointers would help,

thanks

chuck

 

[Henry Paul]

Could be.

I'm not sure what engine you have, but on my 2.2 the cam sensor is on the
back of the rear timing cover for the driver side cam shaft. You can see the
molex plug there on the back.

 

[beertender]

Hello all,

It's been a few years since I've posted, but I have a new problem.

Tried to start my '92 subie legacy an hour ago and got an interesting sound.
No start and a 'skipping' sound from the engine. I'm getting what sounds
like compression on at least one cylinder and nothing out of the others. As
I crank the engine, the sound changes, as though I'm getting compression in
other cylinders. My first thought was a broken timing belt, but if that
were the case I don't think I'd be getting the changing sounds. On my last
crank one of the cylinders hit, but still no start.

I ran the OBD and it came up with error code #13, a cam position sensor.

What's up with this? Would a bad sensor screw me up that bad?

Any pointers would help,

thanks

chuck

Trust your first impression.

Sounds like maybe you wiped a bunch of teeth off the timing belt, and it
is still going around (kinda), but slipping more each time the stripped part
reaches the crank pulley.

Been there, done that. Glad the 2.2 is non-interference.

zero

 

[Spinifex]

AUSTRALIA

Can somebody please explain the difference between an "interference
engine" and a "non-interference" model???

And can somebody please define which Subie engines are which... at least
in the Japanese produced, Australian spec engines???

Cheers
Spinifex

 

[Ned Pike]

In

AUSTRALIA

Can somebody please explain the difference between an "interference
engine" and a "non-interference" model???

An interference engine is one where the piston and valves can hit each other
if the timing belt breaks. A non-interference engine will not munch parts
if the timing belt breaks.

 

[Henry Paul]

As far as I know the 1.8 and 2.2 are non-interference and the 2.5 is an
interference engine.
This refers to the Asian-built engine lines, which are also used in the US
lines as far as I am aware.

The travel of the valves and pistons will interfere with each other if not
synchronized via the timing belt. So for those engines make sure to change
the belt at the recommended intervals and you should be fine.

 

[charl]

Took the belt cover off. Belt is in good shape. Not bad looking afterr
199,800 miles

Then I took the Cam Pos. Sensor out and cranked it. Sounds more 'normal'
when cranking. Put the sensor back in and it again has the funky changing
rythm when I crank it.

I'll check the timing marks on all three pulleys tomorrow in the daylight to
be sure.

The CPS doesn't influence any valve advance/retard does it? Could that be
causing the changing rythm?

Thanks,

chuck

 

[Henry Paul]

That's great if the belt has survived for that many miles. The recommended
change interval is 60k miles and 105k for newer models. I asked the dealer
about my '96 and he said 105k was fine for me.

Make sure you check the belt top and bottom. Look for damaged teeth or
cracks in the belt. You can pull the coil wire and crank the engine a couple
times so you can see the whole belt.

I am not 100% on this, but I think the CPS works with the ECU to dynamically
control the timing. So if you had a knock, the ECU could use data from the
CPS and knock sensor to adjust the timing.

 

[Spinifex]

AUSTRALIA

Thanx Ned for you response.
Can you, or anyone else, please possibly detail which Aussie or Jap Spec
(for our limited range of Jap-imports) motors are which?

Thanx
Spinifex

 

[Spinifex]

AUSTRLIA

Without trying to sound TOTALLY stupid, I am not an engineer, but have a
keen interest. How do they make it non-interference? Is the stroke of
the piston simply too shallow to hit? Surely this must mean those
non-interference motors are fairly low compression, compared to 2.5?

Also, I'm not saying you are wrong, but just out of interest, I snapped
the right bank timing belt on my old 1982 Leone 1.8L. The engine still
ran on the left bank only for 2 kilometres until I found a safe exit
from the freeway I was on at the time.

Upon giving the car to my mechanic friend, as payment for an outstanding
debt ( !!! ), he promptly rebuilt the motor and sold the car for $600.
Debt paid, with MUCH interest!!!

He informed me that I had managed to bend a few valves in the process.
I don't know if they were bent previously, or bent due to the snapped belt.

Cheers

Spinifex

 

[Ignignokt]

AUSTRLIA

Without trying to sound TOTALLY stupid, I am not an engineer, but
have a keen interest. How do they make it non-interference? Is the
stroke of the piston simply too shallow to hit? Surely this must
mean those non-interference motors are fairly low compression,
compared to 2.5?

In a non-interference engine, the piston will not hit the valves when the
former is at the top of its stroke and the latter at their max opening. An
interference engine relies on the valves being closed before the piston
reaches the top of its stroke, and as a result is vulnerable to significant
damage in the event of a timing belt failure. And yes, my understanding is
that one can only reach a certain level of compression before an
interference design must be implemented.

He informed me that I had managed to bend a few valves in the process.
I don't know if they were bent previously, or bent due to the snapped
belt.

This sounds like exactly the sort of damage that results from an
interference engine losing its timing dive mechanism.

- Greg Reed

 

[charl]

Henry Paul wins the prize.

I checked the whole belt and sure enough about 8-10 teeth were stripped out.

This would be the second timing belt I've done on a legacy (first time for
the '92) and generaly speaking, working on Subies is relatively easy and
straight forward.
*but not this time*

I had a heck of a time aligning all three sprockets. I was always just one
notch off either on left cam, right cam or the crank. To add to the mix
there's a misleading arrow on the crank sprocket that gave me hours of
frustration before I figured it out. The arrow on the face of the sprocket
is NOT top dead center, rather, the timing mark is on a four lobed plate
behind the sprocket right under the crank position sensor.

Once discovered the car went back together quite easily and is ready for
another 190,xxx miles. Unless, that is, I've torn up the new belt too much
in the process.

Thanks,

chuck

 

[Spinifex]

AUSTRALIA
Thanx Greg for the explanation.

I was just curious from the previous posters thoughts that the 1.8L was
NON-interference... when I managed to bend valves in MY old Aussie spec
(Japanese production) 1.8L

Does anyone know if Subaru has a detailed engineering website on their
engines/electrics, etc??? Or do we have to buy a detailed manual for
all those bits of information???

Spinifex

 

[Henry Paul]

UTAH

That's a good question. I'm not totally sure how they do that, but the angle
of the valves plays a role also. Not just the valves hitting the piston, but
the intake and exhaust valves hitting each other on a dual-cam application
anyway.

As far as I know the 1.8 and 2.2 are non-interference. However, the modern
1.8 has only one timing belt (Impreza/Asian) as does the 2.2. I suspect the
valves bending in your experience may have been due to stress from only
running on half of the engine perhaps?

 

[Henry Paul]

I had the same problem doing my dad's '95 1.8. I couldn't for the life of me
get everything to line up exactly right......... I did the same thing also,
I was looking at the wrong mark on the crank. (haha) I managed to get the
yellow belt marks inline with the cam and crank mark as well. Whoever did
the job before, had the belt marks no where near the sprocket marks..... I
guess it doesn't matter as long as there are the correct number of teeth on
each side, but for me it seems easier to line up the marks than to count all
the teeth.

I am about 3k miles from doing the same thing to my '96 2.2.