01 outback valve cover gasket failure :-\

[Todd H.]

FYI, updates on this still unresolved saga....

Well poo.

At 108k looks like I'm in the market for new valve cover gaskets. The
car had been doing some goofy hesitation surging during onramp
acceleration. Fairly consistently betwwen 3000 and 4000 RPM, I'd get
a surge/hesitation where things just weren't smooth. You couldn't
maintain that rpm if you wanted to really, but once the upshift
occurred and you were back under 3k things seemed fine. It's been
doing this for oh about 2 months now. Finally I got a check engine
light that then cleared itself 2 days later.

A code read after the fact indicated it was a catalytic converter code
(can't remember if it was front or read). Since the CEL never came
back, I've been driving it for 2 months now.

For what it's worth, it was
P0302 Cylinder 2 misfire detected (which corresopnded to the
cylinder that had a plug boot dripping with oil)

Finally, yesterday, the hesitation/surge thing has really gotten
annoying, I got another check engine indication and took it my
mechanic this morning.

This time the code is MISFIRE CYLINDER #2, which made sense to what I
was feeling when driving.

We pull the (new as of 2.5 months ago) plug wire out of the hole and
find oil dripping down the snout of the wire. Dx: failed head
gasket cover, oil saturates wire, causes the arc and misfire when
engine's struggling under load.

We pulled a wire on the other side of the engine and there was a
little oil on it too indicating that side also need a new valve cover
gasket.

So, here's where we've been since:

Diagnostic on catalytic converter showed excessive heating/blockage,
(so perhaps the cat check engine light code wasn't completely
worthless).

Dye test on head gasket showed a small internal breach. Shocking.
Head gasket problems on a 2001 2.5L?

So we rebuild the heads both sides, replace the cat to the tune of
$1800--New head gasket (aftermarket--wee!), new valve cover gaskets,
seals etc, defect out the plug wires and plugs and all that jazz.
Life should be swell right? Nahhhhhh.

Friggin stumbling/surge at 4000rpm persisted, but it was intermittent
and generally only detectable after about 20min or so on the highway.
Along with it, a mild bucking at 1250rpm on decel/coasting also became
noticeable. So we limp around with that issue for a couple weeks
since we want to give the rebuilt heads some breakin time and not rush
to judgement. About 900 miles later, same crap is still happening and
we finally get enough misfires to trigger another CEL code. This
time:
P0341 Camshaft position sensor circuit range/performance problem

So what the heck, we replace the cam sensor. $150 job. I get teh car
back -- and no fix. Rough running in similar rpm ranges
intermittently, and eventually the car did throw a check engine light
(CEL). After sitting overnight in the garage though, before I coudl
take it in, the CEL code cleared. Furthermore, when my mech went to
read it, there was no code stored in memory this time.

At this point my mechanic and I are both frustrated with this headache
PITA intermittent problem, and a nicely timed vacation allowed me to
leave it with him to drive for 2 weeks with the Dx computer connected.

With the computer, he was able to graph cam and crank position sensor
readings, and showed anomalies with these readings being out of sync
when the misfires were occurring, and sometimes getting crankshaft
sensor codes. During diagnosis and work, it was also noted that
moving the actual wiring harness seemed to trip a code on at least one
occasion. Continuity checks fine on all conductors though, so we have
something intermittent--which as anyone who's tried to repair
christmas lights knows, can be quite a pain. So, the last piece in
that circuit is a common wiring harness that is shared by the crank
and cam sensors. That part is due in today and will get replaced
today. Meanwhile the crank sensor was replaced to rule it out (not on
my dime though) as it did have some indications of damage on it in
addition to the crankshaft codes that were being thrown (but not
always remembered or stored after powering off the vehicle).

During this time, my mechanic enlisted the help of another independent
master mechanic shop owner on this and got frustrated enough to call a
local subaru dealer to bring it in on his dime for them to take a wack
at it. After a long talk on the phone with their lead tech, he
confirmed that these problems are frustrating and that he was doing
all the same things they'd be doing, right down to having the same
model of diagnostic computer they were using.

This car hates all of us right now.

So, I've had the car for the past few days after the crank sensor was
replaced. Our stumble/surge at 4000 rpm on accel and 1250 on decel
still persist. After enough of those misfires, I get a CEL and the
codes I'm getting now, before the harness replacement:
P0301....Cylinder 1 Misfire Detected
P0302....Cylinder 2 Misfire Detected
P0303....Cylinder 3 Misfire Detected
P0304....Cylinder 4 Misfire Detected
P0341....Camshaft Position Sensor 'A' Circuit Range/Performance (Bank1 or Single Sensor)

Fun fun. I'll report back after the wiring harness is replaced. If
that doesn't fix it...... not sure if the ECU is just going nuts
(that not remembering codes thing has me concerned) or what the hell
is going on.

Best Regards,

 

[.._..]

Aside from the CEL codes concerning cam shaft, what you describe it does
during driving is the same thing mine went through (2001 Outback 76k
w/possible head leak), mine turned out to be a bad O2 sensor.

I guess what happened was it lost or threw bad data, and sent all sorts of
stuff "downstream" out of whack including; misfires, hesitation while
acceleration (almost like a tranny problem), raw gas dumped through cat, no
accelleration when hot/moist/raining weather, and "surging" while coasting
down hill (does it stop surging if you put it in neutral?).

It NEVER threw a code except after about six weeks of on and off problems.
One day it would be fine, the next it would be terrible. I'd stop, and
restart, and it would be fine, or not. Once the O2 sensor finally quit,
then it coded bad O2.

A lot of the stuff you did probably needed to get done anyway due to the
gaskets, but I am wondering if you should try a new O2 sensor before doing
more complicated stuff.

 

[Todd H.]

Aside from the CEL codes concerning cam shaft, what you describe it does
during driving is the same thing mine went through (2001 Outback 76k
w/possible head leak), mine turned out to be a bad O2 sensor.

I guess what happened was it lost or threw bad data, and sent all sorts of
stuff "downstream" out of whack including; misfires, hesitation while
acceleration (almost like a tranny problem), raw gas dumped through cat, no
accelleration when hot/moist/raining weather, and "surging" while coasting
down hill (does it stop surging if you put it in neutral?).

It NEVER threw a code except after about six weeks of on and off problems.
One day it would be fine, the next it would be terrible. I'd stop, and
restart, and it would be fine, or not. Once the O2 sensor finally quit,
then it coded bad O2.

A lot of the stuff you did probably needed to get done anyway due to the
gaskets, but I am wondering if you should try a new O2 sensor before doing
more complicated stuff.

Thanks for your reply. I think I stumbled upon a very similar story
to yours at the nasioc forum, and informed my mechanic (who is far
from dedicated to Subes unfortunately) the "might try an O2 sensor if
all else fails--seems it cleared up a really puzzling case with
similar symptoms" and he acknowledged having seem a similar story
somewhere.

In my case, there seems to be an ambient temperature dependency like
yours (hotter=bad), but opposite your experience with moisture. For
instance, recently, it rained and cooled things down to around 70F.
While raining and cooler, the car ran with no problems. Hot and
dry seems to be problematic.

But at any rate, if this wiring harness replacement doesn't fix it,
swapping 02 sensors sounds like the next cartridge to put in the ole
shotgun. I agree that the rebuilding of the heads and getting an
aftermarket head gasket done was a "sooner or later" proposition as I
try to pull some feel-good math of this little journey. *sigh*


Best Regards,

 

[google]

Hi

I just went through the same kind of problems

Hesitations on accelleration and decelleration, almost stalling on
stops and red lights, lack of power. Problem worse went hot.

The mecanics changed the cam position sensor, o2 sensor, spark plugs
and wires and the problem was still there.

They finally took the engine out to check something and found out that
the timing belt was off by 4%, I think it had 2 teeth broken or
something. I will get the complete explanation monday.

I have driven it for 1 day and it seems to have solved the problem.

Keep us informed

Fo

 

[Todd H.]

Hi

I just went through the same kind of problems

Hesitations on accelleration and decelleration, almost stalling on
stops and red lights, lack of power. Problem worse went hot.

The mecanics changed the cam position sensor, o2 sensor, spark plugs
and wires and the problem was still there.

They finally took the engine out to check something and found out that
the timing belt was off by 4%, I think it had 2 teeth broken or
something. I will get the complete explanation monday.

I have driven it for 1 day and it seems to have solved the problem.

Keep us informed

VERY interesting, and something I'll be passing onto my mechanic as
this driveability issue started after he did a timing belt on it. It
drove perfectly before I did that $2k worth of preventive
maintenance.

Thanks for your post. I'll let you know what happens.

 

[Todd H.]

They finally took the engine out to check something and found out that
the timing belt was off by 4%, I think it had 2 teeth broken or
something. I will get the complete explanation monday.

Oh, if you could also find out what codes if any you were getting from
your check engine light. I'm seeing misfires in cylinders 1-4 and
camshaft position range/performance codes when/if my issues get bad
enough.

 

[google]

I had

misfire on cylinder 1-2-3-4 (right after changing the spark plugs and
cables)
air/fuel ratio sensor (changed)
camshaft position sensor (changed twice)
and catalytic sensor (not changed)

If you say it started soon after changing the belt then it may very
well be the same problem.

Keep us informed

Fo

 

[Todd H.]

I had

misfire on cylinder 1-2-3-4 (right after changing the spark plugs and
cables)

Have had these on and off most recently.

air/fuel ratio sensor (changed)

I haven't had this 02 sensor code.

camshaft position sensor (changed twice)

I've had this one and had the senosr changed to no improvement.

and catalytic sensor (not changed)

Had this earlier and it accompanied a catalytic converter that failed
a heat test and apparently was partialy blocked. Cat changed, haven't
seen code since. One poster suggested (and it made sense) that
enough misfires throwing gas into the cat will kill it.

If you say it started soon after changing the belt then it may very
well be the same problem.

Eerie. I'll keep ya posted.

 

[Todd H.]

Hi

I just went through the same kind of problems

Hesitations on accelleration and decelleration, almost stalling on
stops and red lights, lack of power. Problem worse went hot.

The mecanics changed the cam position sensor, o2 sensor, spark plugs
and wires and the problem was still there.

They finally took the engine out to check something and found out that
the timing belt was off by 4%, I think it had 2 teeth broken or
something. I will get the complete explanation monday.

I have driven it for 1 day and it seems to have solved the problem.

Keep us informed

You are a godsend.

I finally was able to get the vehicle back into the mechanic,
mentioning this experience of yours, and reminding him that all the
driveability issues happened when we changed the timing belt. He'd
even seen the TSB on the issue and was very careful to rotate the
engine 3x as the procedure states, etc. However, he did indicate that
it's certainly possible for the belt to skip after that point and we'd
never be able to really see it.

So upon inspection today, he found a tooth on the belt that was not
gone--it was just folding over and not holding. Doh.

So he's replacing the belt tomorrow when the belt comes in. We'll see
if that finally gets it. He plans to turn the engine manually as many
times as it takes until he sees the tensioner pumping all the way out.


Best Regards,

 

[Todd H.]

VERY interesting, and something I'll be passing onto my mechanic as
this driveability issue started after he did a timing belt on it. It
drove perfectly before I did that $2k worth of preventive
maintenance.

Thanks for your post. I'll let you know what happens.

As reported previously, turns out I had the very same problem. The
timing belt skipped a tooth when it was replaced. The root cause was
a defective new Subaru OEM tensioner. This was fingered conclusively
when my tech went to replace the belt again and couldn't get the
tensioner to pump up and lock out even after 10 turns of the engine
(only 3 are called for in the TSB on this issue apparently).

Aftermarket tensioner with a spring backup to the hydraulic action is
now on my car and the problem is solved. It's like driving a
different car now as I'd gotten so used to how lousy the power was
during those months we were chasing our tail playing the ODB-II code
of the day game.


I'm not declaring total victory yet though. The car's running great
but there is a new CEL since the new rear cat was defected out due to
a loose internal part. It's now showing a pending:

P0031 HO2S Heater Control Circuit Low (Bank 1 Sensor 1)

My guess is that with the exhaust work they nicked a friggin o2 sensor
heater supply wire. Grrr.

But the car is running well!!! Wee!


Best Regards,