Hard start after sitting for a week, some knocking ...

[Husker]

 I have an 2005 Forester XT (159K miles) that is generally a daily driver however it sat in

the garage for the past week as we were using my wife's car for various
reasons. It was not driven for exactly seven days. Before now I
haven't had any chronic issues out of it other than that bugger of a
P0420 code from the cats that everyone seems to get.


Today I go to fire it up and it won't start right away. Not a dead
battery, starter motor moves just fine it just acts like it's not
getting spark or fuel. Eventually it fires up, runs (albeit roughly at
first) and gets warmed up. The oil level was fine (checked it before I
cranked) and I changed the plugs a few weeks ago. I can't hear the fuel
pump in this thing normally so I can't tell if it was running or not.
I've only had it since April.


I then notice this loud knocking sound and my first thought is rod
knock. But it doesn't sound quite right and goes away after it's warmed
up a couple of minutes. I've attached a link to a video below. It's
usually a bit noisy after a cold start but this was a bit more than
normal.


I also noticed some light white steam or smoke coming out of the tail
pipe. It's very light, hard to see and looks more like steam. No
noticeable smell (smells like fairly standard car farts to me) and it
condenses on cool surfaces which makes me think it's just water burning
out of the exhaust. Doesn't seem to leave a residue either.


As we had to drive around 100 miles today I decided to leave the XT
parked and take the wife's car. We got home kind of late so I didn't
have a chance to take it for a spin to see if the steam would stop after
being warmed up completely. I've attached a video of the tail pipe, as
you can see there's a ton of water in the muffler. After sitting for
8-9 hours today it fired right up like nothing was wrong. No water in
the oil or oil in the water that I have noticed and it doesn't seem to
use oil (at least not much). I've added maybe 1/4 a quart in 3,000
miles and I'm mostly sure that's because the Subaru dipstick won't give
you the same reading twice. Running Rotella T6 currently.  Probably

switching to Castrol on the next oil change.


Any ideas? Maybe an ignition problem? I'm thinking about getting the fuel system pressure tested. 

Just odd that it would show up only after sitting for a week.

 

I think the steam may be a red herring. The knocking is what bothers me the most.  I can't tell

if it's piston slap or rod knock.



Videos:

Engine Knocking while cold, it was a bit louder in person:

Engine running warmed up, I can hear the knock still ever so slightly in person but the video didn't catch it:

Exhaust steam:

 

       

Edited September 7, 2014 by Husker

[987687]

Sounds like any other subaru to me. After sitting a while oil will drain out of the cylinders and the compression will go down a bit just because the residual oil has drained off a bit, so engines often have to crank a bit more after sitting a while.

 

If my GL sits for a few weeks it has to crank over a few times before it'll fire. If it sits a few weeks and I crank it over for 10 seconds with no fuel/ignition, then hook those up and crank it again. It starts up like it's warm. Likely the same deal going on with your car. 

[Husker]

Sounds like any other subaru to me. After sitting a while oil will drain out of the cylinders and the compression will go down a bit just because the residual oil has drained off a bit, so engines often have to crank a bit more after sitting a while.

 

If my GL sits for a few weeks it has to crank over a few times before it'll fire. If it sits a few weeks and I crank it over for 10 seconds with no fuel/ignition, then hook those up and crank it again. It starts up like it's warm. Likely the same deal going on with your car. 

 

Interesting.  Never had the problems out of the Outback Sport and it sat for a 2-3 weeks straight this summer while we were out and about.  Fired right up like it had never been left.

[Husker]

Also, when I say hard to start I mean it didn't fire up the first 3-4 times I cranked it.  Sorry, I should have been more specific.  On the 4 or 5 crank it slowly sputtered to life.

[lmdew]

Check the CCA of the battery 

could also be a leaking injector is allowing fuel pressure to bleed off

[rverdoold]

bad sparks, bad high tension cables. Dirty valve body. Could be many things.

As long as it does not run bad after it, it is fine. 

Perhaps a thinner oil.

[1 Lucky Texan]

also, after 7 days it could take an extra 3-4 seconds to get the rails pressured up for good injector spray.

 

did the car get its timing belt change at 105K ? might be a weak tensioner letting the belt flop around or ????

[Husker]

also, after 7 days it could take an extra 3-4 seconds to get the rails pressured up for good injector spray.

 

did the car get its timing belt change at 105K ? might be a weak tensioner letting the belt flop around or ????

 

I had some of the maintence records but it wasn't clear what all was changed so I went ahead and had a local shop do it again after I bought it.  That was at 155K.  Better safe than sorry IMO.  I do most of my own work but the timing job on the DOHC can be tricky so

I decided to let someone else with more experience handle it.  The did the whole thing, belt, tensioners, water pump, thermostat, etc.

 

bad sparks, bad high tension cables. Dirty valve body. Could be many things.

As long as it does not run bad after it, it is fine. 

Perhaps a thinner oil.

 

+1 on the thinner oil.  I was trying out T6 but I think the 5W-40 is a bit heavy, I'm going to be giving Catrol a shot.  I used to use M1 5W-30 but both the old OBS started drinking the stuff a couple of years ago so I swaped over to Castrol Synthetic and the consumption stopped.  I think they may have messed with the formula.  Runs fine after it gets warmed up, I was mostly concerned about the knocking be a rod or valve.