Subaru Woes

[Vspec]

Ok so spring is fast approaching and I want to decarb my engine this spring.

I'd like to do a piston soak but because of the flat four design Im not sure if it is possible.

Perhaps Im think I could remove the spark plugs and use Amsoil Power Foam to coat the pistons, how long would I let it sit though? And do I then fire the car with the plugs out or do I reinstall them? I've never done that before.

And i'd like to do the throttle body as well. I was thinking about using power foam again through the throttle body, but I imagine i'd have to do it after the maf sensor.

with engine hot and running have someone vary the throttle at low rpms and spray half a can into the engine while the car is running then turn the car off and spray the rest of the can into the throttle body and let it sit for awhile.

Fire it up let it smoke out and then change the oil and plugs?

Does this all sound correct?

 

[oilyriser]

Why do you want to do a piston soak?

For the throttle body, you can take off the air filter box, and look at the throttle plate area to see if it is dirty.

 

[Gary Allan]

Quote:
I'd like to do a piston soak but because of the flat four design Im not sure if it is possible.


I assume that you have a 4 valve/center plug head design. You could do it ..but you would have to figure out what valves are open and use an adapted compression tester hose. Perhaps a cylinder leakage adapter. It would take a lot of work.

So, I think that you're right.

 

[Vspec]

Actually im an idiot.

The throttle body cleaning would be more difficult, the car is turbo (obviously) with a top mount intercooler.

The intercooler sits ontop of the throttle body so i'd have to remove the intercooler and then open the throttle plate and go to town with the amsoil power foam.

As for the Piston soak, im working on finding a exploded picture.

 

[Dyoel182]

Sounds like it would much easier just to seafoam it a little.

 

[Vspec]

Here are some pictures to help you guys along.

^
In this picture you can clearly see where the sparkplugs are in the EJ257, they are a PITA to install but with the right tools they can be done in roughly...30-45 minutes tops. Im thinking I would have to use a piece of hose to even get any kind of cleaner sprayed into the cylinders.

^
There is another view.

^
Here you can see the top mount intercooler and the throttle body. I dont think I would even attempt to start the car with the intercooler removed, so my only option would be to remove the intercooler and then spray the can into the throttle body\intake manifold and let it sit for awhile then star the vehicle up.

Any thoughts\tips\hints or suggestions?

 

[Vspec]

Bumpalump

 

[Dyoel182]

I still say that seafoam through the booster into the manifold which will eventually soak the chambers when you let the car sit and then start it back up.

 

[Vspec]

I'll keep that in mind, thats kinda hard to do as well....

Hrmmmm

 

[MattPersman]

vacuum line like brake booster is best for this. do it a few times if you desire. one of the good in tank fuel system cleaners should help after the initial decarbon.

or just put a meth kit on it and have constant decarb

 

[Vspec]

^
Above shows the brake booster line area, its kinda a PITA to get too as well.

The other circle is the BPV line which is reported to feed all four cylinders. Im not sure if it would do anything to the upper intake manifold.

Im thinking I could use BGChemtool through that BPV line and then remove intercooler open throttle plate by hand and go to town with Power Foam in the upper intake manifold, let it sit for an hour or so and fire it back up.

Thoughts on that?

 

[MattPersman]

ok I just went out to my car and that small hose there just left (looking in the picture) of the alternator that goes on to the bent nipple on the intake. you could take a piece of 5/16 hose it looks like and put that on there and feed your Chemtool through that. that is where I would do it. I have a FMIC so my brake booster line is more accessible. only thing with taking of your TMIC just make sure you get it back on correctly so you do not have any driveability problems, nothing against your ability as I do not know it, but I have seen people not get a hose on right and have leaks and such. you should however beable to quickly clean your TB then feed the chemtool through the vacuum line it is right after the TB so it will be closest to spraying it right in there for even distribution.

I still like the meth kit idea

 

[Eddie]

Subaru has an engine system cleaner. It consistes of a pressurized? can of an approved cleaner with a hose for the TB. Go to the Subaru websites to get more information. I'm not sure you would want to do a piston soak. In addition, Auto-RX is a very good oil additive that will clean out the ring-pack if that is your motive for the piston soak. http://www.nasioc and http://www.scoobymods are great sites for Subaru information. Ed

 

[westwind999]

What problem are you trying to fix?? If it's just due for a cleaning I'd just use Auto-rx in the oil rather than dumping something in the intake.

 

[Vspec]

I do Auto-RX the engine, but auto-rx does not affect the intake system at all, IE: if the intake manifold has carbon build up with as many miles as my STi has (77,000) im sure it could use a good cleaning.

 

[Eddie]

If your concerned about the intake manifold and related stuff like intake valves then use TECHRON SYSTEM CLEANER (Walmart ~ $9.00 for 20 gal). In addition I would just manually clean the throttle body. Get to the throttle body and spray with THROTTLE BODY cleaner ( not carb cleaner) and wipe both sides of the valve.

 

[Titan]

I'd personally just wash the car and wax it if I were looking for something to keep me busy. B-)

 

[saaber1]

Originally Posted By: Eddie
If your concerned about the intake manifold and related stuff like intake valves then use TECHRON SYSTEM CLEANER (Walmart ~ $9.00 for 20 gal). In addition I would just manually clean the throttle body. Get to the throttle body and spray with THROTTLE BODY cleaner ( not carb cleaner) and wipe both sides of the valve.


Have used that air intake and throttle body cleaner on tons of cars, european, japanese, american. It works excellent. Cleans your intake, intake related hoses/pipes and throttle body extremely well. Great fix for cars with sensitive air/idle control vales etc. that start to have a mind of their own when gummed up. Use the whole can (1/2 can at a time for a turbo).

Techron is great stuff also.

 

[mechtech2]

I'd use a good cleaner in the fuel, instead of any added to the intake or spark plug holes.
Maybe a little water trickled in the intake [keep the engine revving].
But an in tank cleaner will do the CC cleaning and MUCH more.
Chevron Techrom, Gumout REGANE, or Redline S1

 

[westwind999]

Not all cars get dirty intake manifolds. I'd take the throttle body off and clean that and have a look inside. It's a better way to clean the throttle body anyway. Sucking some crud that was stuck on the intake manifold through your valves isn't always good. If you don't actually have a problem I wouldn't mess with it too much. Some Techron in the gas and Auto-rx in the oil would be as far as I would go.

I pulled the intake off of a 93 Subaru with well over 200,000 miles and it didn't need any cleaning at all. The valves were also in good shape.